The clearest correlation to running related injury appears to be training error, which is estimated to account for 60-70% of injuries. But less clear, as this paper digs into, is which variable is most at play: volume, duration, frequency, or intensity? In an attempt to quantify “training error” and provide some guidelines, we have what’s come to be known as the 10% rule. The basic premise here is that you shouldn’t increase your weekly running volume by more than 10% over the previous week. But the 1st rule about rules is that there are no rules. So, this is more guidance than gospel. 

What might be closer to a rule is that injuries happen when the load that’s placed on the body exceeds the body’s ability to tolerate that load. In this equation, we can modify load via training parameters like the variables that the article above attempted to dissect: weekly volume, duration of runs, frequency of runs, and intensity (speed and/or elevation gain and loss). We might further modify running load via surface (pavement vs dirt), footwear quality, and running form (more on that in a minute). On the other side of the equation, we can modify the body’s ability to tolerate load via exercise and preparation for the demands of running (much more on that in a few minutes).

Just like there is no perfect skiing technique, there is no perfect running form. However, in both sports we do have an optimal range, and when movement patterns fall outside of that range they become inefficient. Decreased efficiency equals both decreased performance and increased load, neither of which are desirable. Inconveniently (again), it’s very hard to define what proper running form looks like. It’s maybe easier to define what it doesn’t or shouldn’t look like. Even then, there are only a handful of moderate correlations between aberrant running form and injury. 

At the top of the list is overstriding, aka landing with your foot well out in front of your body’s center of mass. (This is not to be confused with heel striking—landing with initial foot contact through your heel as opposed to mid foot or forefoot. Heel striking isn’t necessarily overstriding though most overstriding does tend to be characterized by heel striking.) The primary issues with overstriding are an increase in peak/impact forces and a decrease in control of the knee, both of which are going to increase load on the body. Without diving too deep into the rabbit hole, the best way to correct an overstride is to increase the cadence or steps per minute—more steps at the same speed equals a shorter stride length. To train this, you need to be on a treadmill at a fixed speed (if you try to increase your cadence outside, you’ll likely just run faster) with your steps timed to the rhythm of a metronome. The target is to increase your steps per minute by 10%, which has been shown to effectively decrease loading rates.

Next up is a lack of pelvic control or what’s often called hip drop or femoral adduction. This occurs when the muscles of the stance leg are overwhelmed and unable to control the hip, and therefore the pelvis. As a result the pelvis drops on the opposite side, altering knee kinematics in the process, and frequently causing knee pain. We look to correct this through exercises targeting hip strength, coordination, and control as well and balance and stability in single leg stance. Conveniently (finally), this would be all of our ski-specific dryland exercises and drills. If you are a FasterSkier regular, then you’ve already seen numerous exercise suggestions here, here, here, here, and here, all of which are quite appropriate for running injury prevention.

That’s a great segue into the other side of the equation: the body’s ability to tolerate load. To paraphrase Geoff Burns, PhD from a recent Science of Sport podcast on running biomechanics, It’s not any one component—joint or muscle—that correlates with injury or performance, but how the system behaves as a whole. We must behave like pogo sticks. More force in equals more force out. But the body must be able to withstand these forces and be able to direct them appropriately. 

Essentially, Dr Burns is saying that running is an inherently high load activity and the body must be adequately prepared (strength, stability, mobility, etc) to handle these loads. Despite Instagram posts proclaiming Five Exercises Every Runner MUST Do! there is no magic exercise. I literally asked three different colleagues, all running injury specialists, What are your top three exercises for preventing running injuries? Inconveniently (here we go again), I got three different answers. 

Not to use that as a cop out, or get away without including pictures of my bald head and yellow-walled basement, here are MY top three exercises for runners (and skiers). These, plus all of your other strength training and pay-to-play maintenance exercises, should be in the mix two or three times a week. As with any exercise, the goal is to challenge or nudge the body in order to get the desired adaptations. This, as with all training, is a bit of a Goldilocks thing: too hot and the body is unhappy and let’s you know about it; too cold and nothing happens. Please be aware that these exercises (and the ones in my previous articles linked above) may not be your Goldilocks. If you are currently dealing with a running related injury (or any musculoskeletal pain), please visit your friendly, neighborhood physical therapist instead of searching for an internet cure.

Triple Extension

This is a classic running form drill to promote pushing through the hip, knee, and ankle. The shape–the ability to fully extend the hip and knee while going high on your toes–is arguably more applicable to sprinters than distance runners; however, it makes my list due to the work done by the calf muscles which are major players in running.

• Stand on one foot about 3 feet away from a wall. Hands are on the wall at about shoulder height. Imagine the wall is falling on you and you need to push it back upright. At the foot, your weight is biased toward the front of the foot so the heel is just high enough off the ground that you could slide a credit card under it.
• Still holding up the wall, drop down into a low squat with your opposite leg trailing behind. 
• With a quick push, stand as tall as you can. You should have equal weight from the inside to outside of the foot, and the knee and hip should be straight, but thinking about getting tall often accomplishes the task.
• If doing this exercise on one leg is too challenging, you can do it both legs together.
• Aim for 2-3 sets of 10x on each side. This is also a good running warm up.

Bulgarian Split Squats aka Trail Leg Lunges

These work the glutes and quads more than squats due to the staggered stance and place more load (and balance demand) on the front leg than traditional lunges. More bang for your buck! The version I’m showing uses a hip strategy/hip hinge/trunk lean to increase the work done by the glutes.

• Feet are staggered with the back foot on a step, box, chair, or bench. 
• To determine the placement of the front foot, sit on the front edge of the step, box, etc. Straighten the working leg out in front of you. Keeping the heel on the floor, stand up onto that leg. Then place the back leg on the step with the sole of the foot vs top of the foot.
• As you drop into the lunge, your hips should go straight down.
• Aim your fingers for the sides of your ankle. This will promote the forward trunk lean.
• The knee will move forward a bit but shouldn’t be going past your toes.
• Shoot for 2-3 sets of 10x. You can make it harder by adding weights or increasing the height of the furniture. It can be regressed by keeping your back foot on the ground.

Side Planks

Typically thought of as a core strength exercise, which it very much is, these also do a lot to  work gluteus medius, a major stabilizer at the hip (see the bit on pelvic drop above).

• Lying on your side, prop yourself up between the outside of your bottom foot and your elbow/forearm.
• Ankle, knee, hip, and shoulder are in a straight line, and your body should be vertical like a wall, not sagging or twisting to one side or the other.
• This is a timed hold. 30 seconds is a win. A minute is a gold medal but is getting boring and ready for some progressions (try it from your hand instead of elbow, add moving the top leg up and down, or twist like you’re reaching the top hand under your armpit). An easier version is to go from the knees instead of the feet (still keep your knee, hip and shoulder in line but bend at the knees so your feet are behind you).

Wall Scrubs

• Lie on your side with your butt 4-6 inches from a wall
• Bottom knee is bent and the top leg is straight
• Push the heel of your top leg into the wall and move that leg up and down
• You should be putting a lot of pressure into the wall—think about scrubbing the wall vs just painting it
• Keep your toes pointed forward not up towards the ceiling
• Pelvis stays vertical and quiet. The motion should be isolated at the hip, not from the pelvis tipping. You can put your hand on the side of your pelvis for feedback to monitor potential movement
• You’ll need to be wearing just a sock or use a washcloth on your heel to reduce friction on the wall
• 3 sets of 10-15 reps (if you’re not getting much fatigue with 15x, add a resistance band around your knees)

Banded Side Steps

• Put a resistance band around your ankles
• Bend and the ankles, knees, and hips like the ski stance
• Keeping tension on the band throughout, step sideways leading with the knee rather than reaching with the foot and shifting your weight
• Band position variations: band around the knees is a regression offering less resistance and possibly more cuing to lead with the knee vs the foot; band around the feet is harder with more work at the ankles but requires a durable band not the cheap ones we give to patients in PT
• 2×15-20 steps or whatever length of hallway you have 

Curtsy Step Downs

• Stand sideways on the bottom stair or a plyo box
• The foot at the edge of the stair will be the working leg
• With the other leg, reach behind the stance leg and tap the floor then finish with knee high
• The working leg will be doing a single leg squat so look to keep your spine neutral, hinge through the hips, lean forward with the the trunk and your butt goes back
• Ideally, this is also a balance exercise with the non-stance leg never taking any weight. However, if this is a struggle, use a railing or wall for assistance
• You can add weight for additional resistance 
• 3 sets of 10x

Lateral Bounding

• Think of these as hopping side steps
• Start in the ski stance position
• Push/hop sideways off the stance leg and land on the other leg in a balanced position
• Switch back to the working leg and go again
• As described, you’ll be moving sideways like down a hallway. If you’re tight on space, you can go back and forth from right leg to left leg but strive to be honest about the balance before the next hop
• Look to do 30 contacts/reps on each side split into sets however your space allows (2×15, 3×10, 5×6, etc)

Lateral Countermovement Jumps

• Stand sideways on the bottom stair or a 8+ inch plyo box
• Step off, landing in the ski stance position on the opposite leg
• Rather than pausing in a balanced position, immediately hop back up to the standing leg on the stair/box
• Think of the landing leg as being a spring or pogo stick that will bounce back after being compressed—the compression will create the ankle, knee, and hip flexion inherent to ski stance, then we want to rebound off quickly and pop back up to the box
• Make sure the work is being done by the landing leg vs just stepping back on the box
• 2 sets of 5-10x. You can add weight or increase the box height for more difficulty (with a med ball or dumbbell held in both hands, move it from chest height while standing on the box to the hip of the landing leg on the floor)

The big toe is called the big toe because it’s bigger than the other toes. It has bigger bone and muscle structure because it takes more load. When we walk and run, we are programmed to get the big toe on the ground. But how and when we get the big toe to the ground can cause problems. Too much, too soon, too late, or too fast and efficiency suffers. When efficiency decreases, loads increase, which does not make for happy feet. All these factors are part if skiing, just as they are part of walking. And the big toe is the key . . .

From Supination to Pronation

In normal walking gait, when the heel makes the first point of contact with the ground, the foot is in a supinated position—the inside of the foot is angled up and outside of the foot is angled down like when you check to see if you stepped in dog poo. In supination, the foot is fairly rigid due to joint mechanics. As we move over top of the foot in mid stance, the joints unlock and the foot moves into a pronated position—the inside of the foot is down and outside is up (literally the opposite of supination). This movement into pronation creates flexibility in the foot, which helps to dissipate impact forces and adapt to uneven surfaces. By the time we get to the last bit of contact with the ground and roll off of the toes, the foot stiffens up again to create a rigid lever. Running gait follows the same general pattern but changes somewhat based on whether the initial contact happens at the heel, mid foot, or forefoot. 

Feet come in many different shapes and sizes, but when the quantity or timing of the transition from supination to pronation is outside of the normal range, the movement pattern becomes less efficient, likely compensated, and potentially pathological. Too much and too soon, both tend to cause an inward rotation of the leg, which is a common culprit in knee pain. Too little or too late can lead to lateral foot issues, greater risk of ankle sprains, and adverse effects from rapid internal rotation of the lower leg as the foot dives onto the big toe right before it leaves the ground. (I have just presented a gross oversimplification of foot and ankle kinematics. For a deeper dive, check this tutorial or get a PhD.)

The control and coordination of this transition from supination to pronation to push off is dependent on joints with their associated ligaments and on muscles. The foot and ankle are comprised of 28 bones, 33 joints, 112 ligaments, 21 muscles in the foot, and 13 muscles in the lower leg. There’s a lot going on here, folks. To oversimplify once again (and to eventually bring this back to skiing), I’m going to focus on two of the star players: tibialis posterior (TP) and flexor hallucis longus (FHL). 

Both TP and FHL are long, thin muscles located in the lower leg along the medial side of the tibia. By the time they get to the ankle, the muscles have turned into tendons that wrap around the inside of the ankle bone (medial malleolus) and head into the foot. 

TP attaches to the navicular and cuneiform bones in the mid foot. Its primary role is to control the movement of the mid foot and support the medial longitudinal arch (i.e. it controls pronation). But it also stores energy and helps the foot rebound from flexible pronation into the rigid lever for toe off. Think about the suspension on your mountain bike: ideally we get a plush ride with the right amount of rebound to set us up smoothly for the next bump. Not enough air in the shock and ooff, we bottom out (too much pronation). Not enough rebound, the shock is too slow, and we feel every one of those roots (the foot stays too flexible for efficient toe off). 

The tendon of FHL runs all the way out to the big toe. Not only does it pull the big toe down, or more functionally, keeps the big toe from collapsing under the load of toe off, but it also helps maintain the structure of the medial arch and mid foot. It works together with its neighbor TP on that transition from supination to pronation to rigid lever.

Reading Break & Audience Participation: 

Take off your shoes and stand up. Use a wall or counter top for balance and do a few single leg heel raises on each side. Have a look down at your foot. Does the movement or line of force go through the middle of the foot or do you end up more on the pinky toe side? Ideally, it should feel like the line of force goes between the first and second toes like it’s following the arrow made by the straps on a flip flop. If you’re way more on the pinky toe side, it’s likely that TP and/or FHL are asleep at the wheel.

As Applied to Cross Country Skiing

In cross country skiing, the biomechanics change, but the demands on TP and FHL remain very high. Biomechanically, we can describe the phases of cross country skiing in similar terms as with walking and running gait: initial contact, mid stance, and toe off. The position of the foot and ankle (and arguably the rest of the body) are very similar during initial contact (assuming V2, not steep V1) and mid stance for both skate and classic but different from walking/running. Rather than a transition from supination at initial contact to pronation at mid stance, we are striving for equal pressure across the width of the foot through both of these phases. “Finding the outside of your foot” is optimal for balance, stability, and glide. Through these two phases, TP and FHL are working primarily as stabilizers of the ankle and mid foot to facilitate balance on the gliding ski. At toe off, aka push, aka kick, skate and classic become quite different from each other. 

Classic Skiing

Toe off in classic is not that dissimilar from walking and running. As I described above, we’re looking for the line of force to run between the first and second toes. Perhaps the biggest divergence is the flexion angle of the ankle as we transition from mid stance to toe off: there is far more ankle dorsiflexion during skiing. While this article is meant to focus on the big toe, it should be noted that a lack of ankle dorsiflexion mobility, both in quantity and quality, will adversely affect not only the mechanics at the foot but also the skier’s ability to get their center of mass over the kick zone. Speaking of range of motion, the first metatarsal phalangeal joint (MTP)—where the toe meets the foot, aka ball of the foot—must also have good dorsiflexion mobility (sources cite 60° for walking and likely more for running; I’ve not seen a study that examined the requisite for skiing). The demands on TP and FHL continue to be focused on foot and ankle stability through the toe off phase; however, if the skier is losing balance and falling towards the other ski (or pronating uncontrollably or internally rotating at the hip or dropping the pelvis or rotating the pelvis or twisting too much through the trunk), the loads on the inside of the foot and big toe will be much greater.

Toe off with skate gets very interesting (assuming you’re finding any of this interesting). Skate boots, unlike classic boots, have minimal flex through the sole, thus the MTPs joints do not have much of a mobility requirement. Skate boots also have a stiff ankle cuff to minimize medial and lateral motion at the ankle. And theoretically they have a supportive insole. But the boots can only do so much.

Skate Skiing

In skate skiing, we have to put the ski on edge. This is a very different movement than with walking, running, classic skiing, or most any activity outside of actually skating. Theoretically, we can get the ski on edge by pronating the foot, internally rotating the tibia, and collapsing the knee–unfortunately, this is how many people ski. But this has the effect of decoupling the foot and lower leg from the power producing muscles (quads and glutes). Instead of sending the force into the ski for a strong push, the energy is lost to aberrant movement (and generally a controlled fall onto the glide ski rather than a coordinated transition). Best case scenario, you’re bleeding power. Worst case scenario, you’re setting yourself up for injury at the knee (most likely), foot/ankle, and/or hip. 

Skate toe off should happen with the ankle, knee, and hip in line. During the transition from flat ski to edge, the line of force through the foot will move medially onto the first MTP. Pushing power is coming primarily from the quads extending the knee and the glutes extending and abducting the hip. But all of this big muscle power must be transferred to the ski. FHL and especially TP are working very hard to maintain joint stability to essentially lock the medial ankle and foot into a rigid conductor of force. While there is active ankle plantarflexion that occurs during this phase, the majority of work by FHL and TP is through isometric contraction rather than creating joint movement. A lack of adequate strength or coordination of TP and FHL will likely lead to a breakdown of this connection. Biomechanics suffer, power is bled, and pathology may surface.

Admittedly, this movement pattern of primarily isometric ankle eversion and plantar flexion while pushing off an angled surface is very difficult to simulate with dryland exercises. However, there are multiple ways that we can still address the concept and strive to make TP and FHL more resilient and tolerant of load. 

There are a number of Physical Therapy exercises that can assist skiers in creating proper foot/leg alignment over the big toe:

Banded Big Toe

This has to be the coolest Physical Therapy exercise ever! Hook a resistance band under your big toe and pull tension. Lift the toe off of the floor and push it back down. Keep the toe long (don’t let it curl up). Also, try not to let it push into the second toe (if you can’t control this, have bunions, or are not getting your toe very far off of the floor, it might be worth a visit to your friendly neighborhood PT).

Heel Raises with Tennis Ball 

Squeeze a tennis ball between your heels and do calf raises. Use a wall or counter top for balance. The ball will keep you symmetrical and help direct the line of force between the first and second toes. 

Single Heel Raises with Incentive Band

Place your first MTP and big toe on the edge of a resistance band. Use one hand against a wall for balance and use the other to pull tension on the band. Do single leg heel raises. Don’t let the band come loose from under your toe and pop you in the face.

SLS with IR Paloff

Balancing on one leg in Ski Stance, hold a resistance band coming from the same side as your stance leg. Push your hands straight out and back. Keep the first MTP and big toe grounded. Don’t let the band twist you.

There are always more exercise options out there, and anything that involves single leg stability is going to be beneficial, but these are a few of my favorites that are a good bang for the buck without fancy equipment. If you like fancy equipment, I would highly recommend the MOBO Board, which does a better job of training FHL, TP, and the rest of the foot/ankle team than any other gizmo I’ve come across.

“Big motor, lousy suspension.” That’s how I often describe the endurance athletes I see in physical therapy. They have the physiology to go fast but are lacking the stability and/or coordination for efficient movement. Decreased efficiency equals increased load. And excessive load has led to injury and a visit to their friendly, neighborhood PT. 

I used the same description while Greta Anderson, the US Cross Country Development Coach, and I stood trackside last August watching rollerskiers during the 15k Classic race in Trollhatten, Sweden. At that high level of racing, everyone was fast, but not everyone looked to have good stability, movement coordination, and efficiency. Our peanut gallery coaches’ box banter turned into a lengthy conversation on the fundamentals of Nordic skiing. Next thing I knew, Greta had me leading a training session for the National Training Group (NTG) and National Elite Group (NEG) combined camp in Park City, UT. We called it Stability From the Ground Up with the goal of reinforcing the Ski Stance while balancing on one leg and doing tricks. The following is an excerpt of that training session. 

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What is Ski Stance?

It is the foundation of Nordic skiing, both Skate and Classic. It is the stable, balanced position on the glide ski that facilitates both optimal glide and a stable platform as the glide ski becomes the kick ski. Stable glide begets more power, and more power begets more stable glide

Ski Stance Checklist:

• Balance on one leg.
• Equal pressure between the inside and outside of the foot, especially across the metatarsal heads between the ball of the foot on the big toe side and the pinky toe equivalent. 
• Weight is biased towards the front of the foot but the heel stays down. Distribution is in the neighborhood of 70:30, forefoot to rearfoot. 
• Toes are relaxed. This doesn’t mean the toes are hovering off the ground, but it very much means the toes are not clawing at the floor. (Have a look at the insoles of your ski boots: if there is a lot of wear under the toes, you are likely using them too much. This is either a bad habit or a compensatory strategy, or both. Speaking of insoles…)
• The ankle is flexed enough to put the kneecap in line vertically over the toes. 
• Slight bend at the knee and hip.
• Forward lean at the trunk. This is accomplished with a hinge at the hips, not a flex through the spine. Nose-Knee-Toes is the old cue. If you’re dripping snot out of your nose, it should land on your foot not down the front of your shirt. 
• High Hips. If I had a dollar for every time Devon Kershaw has endorsed a skier with “high hips” I could buy a ski quiver worthy of the World Cup. But what does this even mean? Our Checklist just listed flexion at the ankle, knee, and hip, so how can we keep the hips high but flexed at the same time? Forward Hips might be a little more intuitive. The pelvis is pushed forward without losing the bend at the hips. It will initially feel like you are falling forward, but that’s a good thing. We want the center of gravity shifted forward to push us down the trail. A different cue is Front seat, not Back Seat. The back seat is like starting to sit on the toilet: ankle, knee, and hip are flexed and the trunk is leaning forward; however, the butt is reaching backwards. Aim to shift the hips forward like someone is pulling at the front of your belt.
• Stability from the hip, not leaning to the side. When we stand on two feet, the center of gravity is between the two feet. If we are to stand on one foot, we can’t just pick up the opposite foot—our center of gravity has to shift to the stance side. That can be accomplished by leaning the trunk to the side, but this is not an active position and doesn’t facilitate generation of power. The weight shift ideally comes via a lateral movement of the pelvis over top of the stance leg. Note: this shift is very applicable to diagonal stride as we move from the kick ski to the glide ski. The direct application to skate varies a bit with the sub-discipline—V1 has a more distinct weight shift from ski to ski while the transition during V2 is more of a “swapping” of skis underneath the body than a lateral movement from one to the other.

Exercises 

The intent of these exercises is to reinforce the Ski Stance. Each one has a movement component to challenge both balance and maintenance of the Ski Stance position. (Here is a primer on single limb balance and stability.) The quality of movement and balance are paramount. In order to be beneficial, the exercise should be challenging but doable. If you are falling all over the place or cannot control the movement, the exercise is likely too difficult for your current level. The exercises are listed in ascending order of difficulty.

Band Poling Exercise

• Ski Stance.
• Use a two-tailed band or two separate bands anchored at head height or higher.
• Pull down on bands keeping some bend in the elbows. (This is not meant to be a double poling simulation as we are trying to stay tall in the Ski Stance not dropping down as we would with DP or V2.)

Romanian Deadlift (RDL) Exercise

• Ski Stance.
• Bend forward aiming your fingers for the sides of your knee. The movement is a hinging motion at the hip. The joint angles at the ankle and knee should not change. The spine stays in neutral position without bending.
• Pelvis stays level as you bend forward (no twisting).
• Finish with a push forward of the hips/pelvis—front seat not back seat.
• You can add weight (single dumbbell or kettlebell in the opposite hand or one in each hand) for glute and hamstring strengthening, it doesn’t necessarily make the balance/stability any more difficult. 

Hip Twist Exercise

• Ski Stance.
• Twist your upper body in the opposite direction of the stance leg (standing on right leg = rotation to the left).
• Shoulders, belly button, pelvis move together. 
• Knee cap stays pointing straight ahead. 

Paloff Press with Resistance Band Exercise

• Ski Stance.
• Band is anchored at chest height coming from the opposite side of the stance leg.
• Holding the band in both hands, push your arms straight out and back.
• Keep knuckles pointed straight ahead—don’t let the band twist you.

Shoulder External Rotation + Uppercut with Resistance Band Exercise

• Ski Stance.
• Band is anchored at chest height coming from the opposite side of the stance leg.
• Hold the band in the same hand as the stance leg with your elbow bent at 90 degrees and knuckles pointed straight ahead.
• Keeping the elbow bent at 90 degrees, raise your arm up as if you were a waiter carrying a tray.
• This is very good bonus work for your rotator cuff muscles.

Classic Stride/Bound with Pause for Balance Exercise

• Traditional diagonal stride bound except with a pause on the “glide” foot.
• Be honest about balancing in Ski Stance before kicking onto the other leg.
• Continue to focus on arm swing mechanics and a strong kick.

Skate Stride/Bound with Pause for Balance Exercise

• Traditional lateral bounding except with pause on the “glide” foot.
• Be honest about balancing in Ski Stance before kicking onto the other leg.
• Continue to focus on both the pre-load and strong push through the leg.

Injuries are inevitable . . .

As a physical therapist, I am often preaching prevention through maintenance exercises and training strategies; however, despite very well intended plans, injuries can still happen. Some of these will be short term, quite manageable, and maybe just a product of bad luck. Other injuries are longer lasting, will likely require some medical management, and are certain to impact training, whether from an acute trauma or from symptoms that have become progressively worse due to overuse/training error. The cool thing is, given the right conditions, the body will heal.

But what are the right conditions for healing? How do I heal faster? When do I know when to resume training? These are questions I get every day in the clinic. I certainly don’t have all the answers, but I’ve compiled a list of what I generally advise patients.

What is pain?

First off, I think it’s helpful to be reminded of what, exactly, is pain? Simply put, pain is a defense mechanism to keep us from harming ourselves. If you put your hand on a hot burner, the body’s response is pain so you take your hand away before it burns. Remember that like all animals, our body’s primary objective is survival (arguably procreation as well, but I’m not going there). Our bodies have a multitude of regulatory systems meant to aid us in homeostasis and survival. When there is an injury, and especially the subsequent inflammatory response, the nerve receptors in the area send a warning signal to the brain which we interpret as pain and thus respond in a way that protects the injured area. But the severity of pain is not always commensurate with the degree of injury. A paper cut hurts like hell, but it’s not going to kill you. Also, the paper cut will stop hurting before the skin has fully healed. The hypothesis is that the body is familiar with the paper cut, no longer sees it as a threat or concern, and stops interpreting the nerve signal as pain (unless it meets lemon juice and the body feels threatened all over again). All of this would seem to indicate that some pain, especially when chronic in nature, does not actually represent a fragility or active threat. This doesn’t mean that we disregard it, but it doesn’t mean that we bow down to it, either.

Pain can be a guide to training and activity; it doesn’t need to be a  contraindication. Typical guidelines will say that pain less than 4/10 (0 is no pain, 10 is going to the emergency room screaming for mercy) that goes away or returns to baseline within two hours of exercise or activity is totally reasonable. It’s a green light, keep on going. Pain in the 4-5/10 range, or lower grade pain that is taking longer to calm down, is a yellow light: you really shouldn’t go through that intersection, so back it off a bit. Pain 6/10 or worse is a red light.

Inflammation gets a bad rap 

We often blame inflammation and the associated swelling and pain as the cause of our problems; however, the inflammatory process is the way our body deals with injuries (and pathogens). The long-held treatment strategy for acute injuries is RICE: Rest, Ice, Compression, and Elevation. This is often paired with anti-inflammatory medications like ibuprofen. This treatment may provide some short-term pain relief—rest means you’re not using it so it’s less likely to be painful, icing numbs the injured area, compression and elevation may decrease swelling and some associated pain, and NSAIDs suppress the pain signal in the nervous system; however, there is mounting evidence that it can hamper appropriate healing in the long term. While we still want to manage pain, the treatment approach is shifting towards early movement with progression back to activity as symptoms dictate. There are certainly caveats to this: I am not endorsing walking on a broken leg or running on a newly sprained ankle—follow your medical provider’s advice.

For long-duration chronic issues, the thought process is a little different: at the anatomical level, we often think of chronic injuries, especially tendinopathies, as a failure of the inflammatory process to fully address the issue. My local streets are full of potholes. In the summer, the street crews patch them with asphalt. In the winter, the snowplows blow out these repairs. Every spring, the potholes are back. This is my analogy for chronic tendon issues: when we sleep the body does a quick, half-assed repair job (patching the pothole) then when we load the tendon the next day, we blow out the repair (the snowplow). What we really need is for the street to be repaved and for the body to appropriately heal the tendon. The street gets repaved when the mayor’s office is tired of the nosey neighbor complaining to City Hall every day. The tendon gets healed when we get the body’s attention through specific exercises. While there may be a role in the use of anti-inflammatories and injectables, the research in favor of exercise treatment is pretty compelling. Again, talk to your medical provider, especially one of my friendly colleagues in physical therapy. 

Focus on what you can do, not what you can’t 

It may be that your symptoms with activity/training are duration- or intensity-dependent; by modifying these variables, you are able to continue at least at some level. Depending on the severity and acuity of the injury, your body may not be in a place to absorb the stimulus of high intensity training. If it is too concerned with survival and homeostasis, it will behave much the same as if you are sick or overtrained: do all the intervals you want, but you’re unlikely to see progress and more likely to see your fitness decline. It may be that an activity (running is likely the first thing that comes to everyone’s mind) is simply not doable and you need to look for alternatives. Cycling, swimming (love it or hate it, but there’s very good carry over to XC skiing), SkiErg, paddle boarding, hike up/chairlift down are all potential alternatives that can still get your heart rate up, get you outside, and keep pain levels in the green light range. Specificity of training is certainly a good thing, but it’s not the only thing. There are lots of ways to get stronger and more cardiovascularly fit. Look at your injury as a way to try new things, master a different skill, and have fun.

Be nice to yourself 

It may feel like your body has betrayed you, but it really is trying to do its best. Treat it with kindness. You don’t have a good knee and bad knee, you have a right and a left. Working through an injury is like powering up that last hill or getting the bell lap when you really just want to puke: they all take self-motivation, self-encouragement, and self-respect (notice the self- theme here). Sleep is a powerful drug. Don’t overdose, but maybe take more than normal (at least 8 hours/night). Eat well and eat wisely. A muscle injury will appreciate more protein. A healing bone will enjoy more calcium. There is a strong tendency to cut back on calories when an injury is preventing normal training volume; however, your body still needs fuel to heal. I am a big fan of acupuncture (disclosure: my wife is an acupuncturist). While the supporting research is inconsistent, the practice does have 6000 years of history behind it. Without delving into Eastern medical philosophy, I will simply say that it has the potential to help the body heal. Having just made a medical recommendation while maybe sidestepping evidence-based practice, I would encourage you to thoroughly research any nontraditional treatments or recovery hacks. You can buy a lot of things with great promise, but the only given is how much lighter your wallet will be. Some may work, some may not: just try to be an informed consumer.

Surround yourself with good people and good energy 

You might need a hiatus from social media, most especially Strava. Interact with people who lift you up and try to avoid the ones who leave you feeling bad about yourself (whether they mean to or not). FOMO (“Fear Of Missing Out”) is a loaded gun—lock it up and throw away the key. Your sport may define you, but it’s not your only definition, and your injury does not need to be one either.

Find medical providers who understand your body’s demands 

I became a physical therapist to help people do what they want, not to tell them what they can’t. But not all medical providers share this sentiment. Telling a patient to stop running or lifting weights because it’s causing pain will likely improve symptoms, but that’s not going to be an acceptable treatment. It may be that the painful activity needs to be modified (and very likely moderated); however, your provider should share your goal of getting back to it. The way I see it, medical providers should be part of the patients’ team—we are working in collaboration to establish a plan of care that is based on both the patient’s goals and the provider’s hypotheses of diagnosis and appropriate treatment. Your provider will need to have a very good understanding of your sport—maybe not all the nuances of technique, but at least the physiological and biomechanical demands on the body. The path forward is often centered around progressive loading, and we as providers need to know what that looks like in order to prescribe the appropriate dosage of volume and intensity, hard days and easy days, stability and strength.

Don’t make the same mistake twice 

The typical medical model is to diagnose and treat. Let’s name it and fix it. This may get you back to training, but if we don’t identify the underlying cause of the injury, we are unlikely to have provided any protection against repeat offenses. I simplify all musculoskeletal injuries as an imbalance between load that is placed on the body and the body’s ability to tolerate load. Excessive load may be in the form of training error (too much, too soon) or through inefficiency of movement. Inability to tolerate the load is due to a deficiency in strength, mobility, stability, and/or coordination. In order to address the issue long term, we will need to balance the equation. That means both identifying and addressing all of the components of the equation. With training error, that means gaining a better understanding of training principles and especially greater awareness of your body’s response to both exercise stimulus and recovery. On the resilience side, it’s likely going to be boring exercises with stretchy bands. Addressing this side of the equation is not glamorous, but neither is pouring the concrete foundation of a house. But both are essential if you want to build something worth living in.  

Most conversations regarding training for endurance sports center on competition: the training schedule is built around the races. But what if you don’t compete? What if you’re out there on the ski trails, bike trails, and hiking trails without a race number? What if your objective is not to podium but to simply enjoy the opportunity to push your body? Is there still a reason to “train” when there isn’t a competition to train for?

Goals

Why do you do what you do? Cross country skiing is not easy. The technique is impossible to master, the fitness requirement is harder than doing all three triathlon disciplines at the same time, and the equipment, despite all of its carbon fiber, provides all the stability of a wet noodle. Yet we’re out there flogging ourselves around the ski track all winter long. The why is very individual but everybody has one. To get your heart rate up, to feel the burn in your muscles (and lungs), to ski for 90 minutes without keeling over, to V1 up that nasty hill (and not crash going down the other side), to V2 gracefully like your World Cup hero, to soak up that euphoric sensation of gliding across the snow. Every time we step into our bindings we have goals, whether big or small. Given the nature of our sport, they will likely be facilitated by strength, balance, and aerobic fitness—all things that can be improved with intentional training. They will also be facilitated by how we frame our goals; are we more focused on the journey or the destination?

Intentional Training

Pay to play. As athletes, we get what we pay for (training-wise). As a physical therapist, I am a huge advocate for putting in some work off of the skis/bike/running shoes. I see a lot of patients whose injuries have come about due to having a big engine with lousy suspension. They’ve built a fancy house on a shoddy foundation. Our sport is great at building the big muscles—the primary movers of the body—but if we’re not training the smaller stability muscles, they often get left behind. Worse yet, we humans are built with anatomical redundancy, meaning that if one muscle, artery, or nerve is injured or not up to the task, we have others that can take over. The problem is that the compensatory Plan B is not as efficient, which leads to increased load on the body, predisposition to injury, and decreased performance. As we get older, our bodies are less concerned with maintaining muscle mass (sarcopenia, in the fancy vernacular). It would also be wise to pick up heavy things. Stability, balance, and coordination with a side of lifting and mobility for dessert. These are the staples of pay to play. I’ve covered some guidance in previous articles on FasterSkier including spine stability and mobility, balance and single leg stability, and the shoulder girdle.

Intent. Every workout or exercise session should have a purpose. That can range widely from the post-work jog to get some fresh air and clear the head so you’re more patient and present at home to the Z4 rollerski intervals where you’re trying to focus more on technique than top speed. These two examples differ in mode and intensity, but they both have a purpose. If the post-work jog is run at high intensity (or has the unexpected stress of a dog chase or near miss from a distracted driver), you won’t have achieved the goal of a calmed state of mind. If the rollerski intervals become too competitive or if the intensity is pushed too hard to keep the focus on technique, you may still get some physiological benefits from the hard efforts but they failed to achieve the purpose of maintaining technique while deep in the pain cave. Even if you head out the door on a run, ride, or ski with no intent other than the pure joy of moving, you may still want to consider how you’re doing what you’re doing to avoid overtraining or pushing too hard without an adequate foundation. 

Scheduling. This may well be the greatest challenge for the noncompetitive athlete. If every workout is hard, then you risk flying too close to the sun. I’ve just preached the gospel of pay to play. In a previous article, I tried to espouse the benefits of lower intensity work. How does all of this fit into the training week, especially when we still want to go out, have fun, and not overthink it? Most coaches and structured training programs will include strength sessions and lower intensity workouts, much as I have just championed, but the hard sessions will likely be rigidly defined intervals or tempo work. If you are a competitive skier with the goal of optimizing speed, these programs are exactly what the science would tell you to do. If you are not regularly pinning on a number, or not willing to be constrained by a formal training plan, you may be wondering where the group ride, social run, family hike, or KOM hunting fits in the mix. The general framework is no differen—a couple of gym sessions, a couple of hard sessions, and the rest at lower intensity. To repeat, The Big Day Out and The Epic Adventure only get to happen a couple of times a week (and ideally not on consecutive days) or you risk overcooking.

Process Goals. For competitive skiers, training is the journey and racing is the destination. For noncompetitive skiers, it’s almost all about the journey. In (very simplified) sports psychology terms, the destination is an outcome and the journey is a process. Framed as goals, or what you’re hoping to achieve, an outcome goal would be a specific result: finishing position, PR, Strava KOM, etc. In contrast, process goals are the pieces of the outcomes puzzle or what it takes to achieve the desired results: quality training (and recovery), appropriate nutrition, adequate sleep. In this study, the authors sought to determine which type of goal was more beneficial. Their conclusions: “Process goals generally enhanced self-efficacy, intrinsic interest, and satisfaction.” More specifically, “Process goals were more beneficial for increasing performance and self-efficacy than other goal types. The latter is a noteworthy finding, given self-efficacy has been shown to enhance decision-making, increase motivational intentions, and is positively correlated with sport performance.”

While the concept of process goals is nothing new in the sport psychology circles, it was cemented for me while I was in Norway with the US Cross Country Team. During a physical therapy session a day or two before the historic women’s 50k at Holmenkollen, I asked Jessie Diggins about her goals for the race. “Well, to win would be really cool.” To which, I replied, “Duh! But what about your process goals?” (Yes, I was baiting her a little.) She proceeded to list three things she really wanted to nail: eat her favorite pre-race breakfast, be thorough and concise in conversations about ski selection, and be extra patient in the feed zones to make sure she was taking in enough calories. 

As a physical therapist, I tend to judge the success of a treatment on whether the patient gets better. However, that is not something that I have full control over. There are many variables that make up a patient’s injury or pain–maybe even more that determine their response to PT–and I can only affect what I can control. Similarly, Jessie knew that once the gun went off, there were going to be a lot of things during the race that were out of her control, so she chose to focus on the things that she could control. That is the basis of why process goals are considered more effective than results goals. 

For the noncompetitive skier, I’m emphasizing the role of process goals because the components of intentional training I pitched–pay to play, intent of the activity, and scheduling–are all process goals. Judging yourself on how you do what you do more so than the end result is likely to bring more joy in the experience. The journey may very well be more important than the destination.

The air we breathe is precious. Whether simply sustaining life functions or powering the aerobic metabolism that gives our muscles energy, we can’t get by without it. Fortunately it is always there (though maybe a bit less so at high elevation), but the quality of the air can vary from sublime to very unhealthy. The main antagonists are particulate matter and ground level ozone.

Airborne particulate matter is generally categorized by size. PM10 is 10 microns or smaller in diameter. This is stuff like dust and mold. PM2.5 is much smaller and tends to pose greater health risks due to the ability of the tiny particles to infiltrate the lungs and bloodstream. Most PM2.5 comes from chemical reactions and combustion like automobile exhaust and wildfire smoke.

Ground level ozone is different from the ozone layer in the upper atmosphere. While the latter helps protect the earth from solar radiation (i.e. good for us), the former can be very irritating to the tissue of our lungs and airways (i.e. bad for us). Ground level ozone is not so much a  thing like PM2.5 particles–it is technically the byproduct of chemical reactions between nitrogen oxides and volatile organic compounds in the presence of sunlight. Basically, pollution + hot sun = ground level ozone.

Geographic considerations. Areas that are prone to temperature inversions where the lower elevation air is colder than at higher elevation–typical of mountain valleys–can see pooling of PM2.5 in the valleys. This is a very common phenomenon during Salt Lake City winters. Thankfully, while the air quality might be very unhealthy in the valley, it can be quite good at higher elevations above the “gunk layer.” Ground level ozone, due to the source of its reactants, tends to be proportional to population density so typically much greater in urban areas. Get out of the city, and you can get out of the ozone. Unfortunately, there is no hiding from the PM2.5 of wildfire smoke, except maybe staying indoors.

Air Quality Index

The Air Quality Index (AQI) is a scale used to report air quality rather than the actual measurement of PM2.5 or ozone. While many state governments and universities have sensors and report measurements, the AQI attempts to rate the current air quality regardless of the pollutant. In the US, the Environmental Protection Agency has categories for the health risks associated with elevated AQI. Last summer, after much research and collaboration, US Ski & Snowboard released its own guidelines for winter sports athletes.

Resources

AirNow.gov is likely the best source for real-time AQI in the US. Additionally it contains a large library of information on all things air quality. 

Purple Air not only sells low cost air sensors for home use, but also makes the data from those sensors available to all. This allows for much more geographically specific information; however, as AirNow points out Purple Air sensors “consistently overpredict fine particle concentrations” so take it with a grain of salt.

The iphone weather app has AQI for cities around the world.

NOAA has a (free) smoke forecast map; however, it is not the most user friendly. 

Open Summit has a very user friendly smoke forecast map but does require a subscription to access. Worth noting, you’ll see that neither the Open Summit nor NOAA maps will forecast more than about 48hrs. It’s my understanding that the computer models that predict wildfire smoke location and density are not nearly as good as those that forecast the weather.

All ski boots come with insoles. None of them are any good. Some might be fair—maybe even usable for those with strong feet, neutral biomechanics, and impeccable technique—but, for most of us, they’re garbage. Literally. Throw them away and get some good insoles.

Why Do I Need a Good Insole?

Balance

Quite simplified, balance is a product of the nervous system. Our eyes, inner ears, muscles, tendons, joints, and skin are constantly sending information through the nervous system so the body can monitor, regulate, and coordinate movements. Proprioception is the fancy term for the body’s awareness of its position in space. Try this: close your eyes and try to touch your nose with your right index finger and then your left index finger. You should have been able to do this easily without poking yourself in the eye. This is because the nerve receptors throughout your arm are part of the feedback loop that guides the muscle contractions responsible for movement.

When standing on one leg (or one ski), our ability to maintain balance is aided by sensory information from the bottom of the foot. Receptors in the skin tell the nervous system how we are standing—if pressure is predominantly through the ball of the foot or the heel, the inside of the foot or the outside. A good insole will enhance this feedback loop by providing sensory information and tactile cues to the nervous system.

Stability

Your foot has 26 bones, 19 muscles (plus another 10 that are technically in the lower leg but act on the foot), and 33 joints, all of which are your body’s connection between legs and skis. The job of the ski boot is to enhance the connection between leg and ski. Boot technology—and, thankfully, color schemes—have improved significantly since the dawn of skate skiing in the ‘80s. Modern skate boots use rigid plastic or carbon fiber in the soles and ankle cuffs to offer external support and decrease the demand on the muscles and joints.

A good insole will also decrease the workload. With skating technique, the joints of our feet should be held relatively still throughout the cycle of weighting the glide ski, pushing off, and swinging back to glide. We want those joints held in place with as little effort as possible. A good insole, comprised of materials that do not collapse under body weight, will support the foot through the calcaneus, tarsal, and metatarsal bones, making it easier for the muscles of the foot to maintain stability. A foot that collapses or changes shape significantly (this is most obvious in foot that has a high arch when held off the floor but a very low arch when standing) is inefficient, increases muscle demand, and likely bleeds power.

Additionally, we want the talocrural (ankle) joint to function in a neutral position. A foot that changes shape significantly is liable to affect the ankle joint in the process. When the inside of the foot drops to the floor, it often takes the ankle joint and thus the tibia (shin bone) with it into internal rotation. Remember that the shin bone is connected to the knee bone and the knee bone is connected to hip bone. By supporting the foot and limiting changes in shape, we can minimize the sequelae of adverse effects up the leg: tibial internal rotation, knee valgus, hip adduction and internal rotation. (If the changes in foot shape are considerable, it may be that a good insole isn’t good enough and a custom orthotic may be better. More on that below.)

What’s a Good Insole?

A try-before-you-buy approach is highly recommended. Perhaps your ski shop, but definitely your local outdoor or running store will have several different insoles to try. And you should try them all… except the squishy ones. We’re looking for support not shock absorption. Desirable insole material should be fairly firm and hold its shape. Rigid plastic pieces are generally ok–remember that your foot is not articulating inside the skate boots. Also, consider the thickness of the insole–best to try them on with your boots to make sure they don’t take up too much volume.

Sizing is more about where the arch hits your foot vs the length of the insole (which can always be trimmed to fit). It’s not uncommon to go up a size or two from what the box recommends.

The insole is there to support your foot, not push it around. The arch of the insole should fill the space between your foot and the floor. Too much from the insole and your foot is going to be pushed onto the outside. Not enough from the insole and you’ve wasted your money. It should be the way Goldilocks wanted it: just right.

Since the whole idea here is for the insole to facilitate balance, stability, and control of the ankle joint, you need to test the insoles: balance on one leg both barefoot and on each of the insole candidates. Repeat the process with a small single leg squat (i.e., go into hip/knee/ankle flexion like glide ski position). The insole should make these tests easier. If it’s more challenging or less stable while standing on the insole, then it’s likely to make your skiing worse. Ultimately, a good insole is one that makes balancing and squatting easier to control.

Additional Comments:

Custom orthotics come in two general categories. One is simply an insole that is custom molded to your foot. This ensures that the insole follows the contours of your foot and fills the arch appropriately. The other is custom molded but includes additional, strategically located material for greater external support of the foot. These can get quite expensive so they’re not typically the first thing to try. However, if you have foot, ankle, or knee pain with skiing, and have already tried some aftermarket insoles, custom orthotics may be very beneficial. I’d refer you to your friendly, neighborhood physical therapist for guidance.

Classic vs skate. As mentioned previously, the joints in the feet have minimal articulation while skating, but we most definitely move through our metatarsophalangeal joints (ball of the foot) with classic. The same general guidance on insoles still holds; however, I’d stay away from overly stiff materials (the insole should flex very easily where your toes would bend). Custom orthotics might also be different between skate and classic where the external material for the skate orthotic might be too obtrusive with the joint articulation in classic boots. The orthotic approach for classic boots will be more like that used in running shoes where there needs to be articulation of the foot joints but we’re looking to support, not block, that motion. In skate boots (also in cycling shoes and alpine boots), we really do want to block the foot motion.

US Ski & Snowboard recently hosted a course titled “Medical Emergencies in Skiing and Snowboarding”, which is required training for all physical therapists and athletic trainers working with the team during competitions. As the name would imply, we learned about emergency management of acute injuries: application of cervical collars, tourniquets, back boards, distraction splints, and plenty of other nasty scenarios we hope to never see. 

Thankfully, cross country skiing tends to be lower risk when it comes to traumas and medical emergencies. Typical of an endurance sport, our injuries are more self-induced from the volume and intensity of training. Instead of blown out knees and broken bones, we contend with tendinopathies, muscle strains, and joint pains. For better or worse, these ailments are quite common, and we’re pretty good about diagnosing and treating them. That might not be the case with a condition called Chronic Exertional Compartment Syndrome (CECS), a painful condition most often affecting the lower leg. It’s common among Nordic skiers, it’s painful enough to seriously disrupt training, and it’s often difficult to diagnose and treat. This article attempts to investigate the condition, and to offer some advice to those suffering from it.

C.E.C.S.

Chronic. It occurs repeatedly and/or persists over time (not the result of a trauma).

Exertional. It happens with effort. This is one of the hallmarks of the condition: symptoms are present with exercise, often only at higher intensities, but tend to subside fairly quickly with rest. 

Compartment. Throughout our bodies we have connective tissue called fascia. I think of it as Saran Wrap. It’s thin, pliable, and has a small amount of elasticity. Our organs are packaged in fascia. Muscles are encased in fascia. The typical physiological explanation for fascia is that it creates “compartments” to reduce the spread of infections or pathogens. (From a musculoskeletal perspective, fascia may play a large role in how our muscles, tendons, and joints interact.)

Syndrome. A group of symptoms that occur together. Generally, not a good thing. 

CECS occurs when exercise causes the muscles within a fascial compartment to become swollen and enlarged to the point of exceeding the space within the compartment. This leads to decreased blood (therefore decreased oxygen supply to the muscles) and ultimately pain, numbness, and/or weakness. 

CECS almost exclusively affects the lower leg, which has four compartments. 

• The anterior compartment contains muscles of ankle dorsiflexion and stability, primarily the tibialis anterior. 
• The muscles of the lateral compartment provide dynamic stability at the ankle. 
• There are two posterior compartments: the superficial compartment with ankle plantar flexors and the deep compartment containing muscles that stabilize the ankle and foot. 

The mechanics of CECS is a simple matter of too much stuff in too little space. The more that muscles work, the more oxygen they need. The body obliges by increasing the heart rate, pumping more blood, and delivering more oxygen. This causes the muscles to swell and take up more space. While the fascia has some elasticity and ability to stretch, it does become quite confining and won’t let the muscles expand any further. This causes pressure to build within the compartment. 

So far, this is all a normal physiological response. But, if the incoming blood flow continues at a higher rate than the outgoing flow, the pressure will continue to increase. When the compartment pressure exceeds that of the blood vessels, blood flow becomes restricted. The muscles become starved for oxygen and will get very pissed off. Pain is the body’s response, yelling at you so you’ll stop what you’re doing and leave the poor muscles alone.

Traits of CECS

Pain is the most common complaint with CECS. It is sometimes accompanied by numbness or sense of weakness. Along with pain, there is often a description of tightness or cramping. As previously mentioned, symptoms arise only with exertion and subside quickly – often within only a few minutes of rest. Symptoms arise only with exertion and subside quickly–often within a few minutes of rest. This is a key trait of CECS.

Location of pain is commonly bilateral and often broad–it takes a whole hand instead of a finger to point to the pain. However, it is almost always within the anatomical borders of the compartment. (This does get more vague when multiple compartments are symptomatic, especially the combination of anterior and lateral.) 

Symptoms of CECS are typically very hard to reproduce without the exertion of the offending sport. This is a clinician’s nightmare as we glean a considerable amount of information when our tests reproduce the patient’s pain.

Taken together, these traits are what will most readily differentiate CECS from other chronic musculoskeletal issues like tendinopathies, muscle strains, or joint pathologies: symptoms subside quickly with rest, are diffuse, and are not reproduced during a physical exam.

Diagnosis

The gold standard is an exercise test using an intra-compartment pressure monitor. It’s basically a syringe needle attached to an air pressure gauge. The protocol is to take baseline measurements at rest and then again after exertion. The pressures are compared using the Pedowitz criteria: “1) a preexercise pressure greater than or equal to 15 mm Hg, 2) a 1 minute postexercise pressure of greater than or equal to 30 mm Hg, or 3) a 5 minute postexercise pressure greater than or equal to 20 mm Hg.” This essentially means 1) your resting pressure is really high, 2) your pressure under exertion is really, really high, or 3) your intra-compartment pressure is not decreasing normally with rest. 

Treatment

Conservative treatment is frequently not very effective but certainly worth exploring, especially if you are trying to make it through competition season. Massage and taping are the most common interventions that have potential for at least short term improvement (if a bit of tape lets you race without pain, that’s a win!). There may be more substance behind altering the movement pattern responsible for CECS in the first place: for example, this study found very positive results by making changes to the subjects’ running gait and foot-strike pattern.

Unfortunately, we are not very good at treating CECS without a scalpel. Surgery is by fasciotomy. Oversimplified, this is a procedure where the fascia is cut to create more space within the compartment. For most surgeons, a positive on the Pedowitz criteria is a prerequisite; however, they will also consider the compartments affected and the severity and duration of symptoms. While not perfect, surgical outcomes tend to be pretty good. A study of elite French skiers with CECS observed that 94% became asymptomatic and almost 90% returned to competition after fasciotomy surgery.

Ski-Related CECS

The article just referenced found the prevalence of CECS to be 6.1% among the elite, national team skiers they studied. It was slightly higher amongst biathletes and slightly lower for cross-country skiers. Symptoms were much more common with skate vs classic skiing techniques, and the anterior compartment was the most commonly affected.

The anterior compartment and skating 

Recall that the anterior compartment houses muscles that generate ankle dorsiflexion, in other words, the muscles that lift the foot and toes toward the shin. When we skate, we lift the kick ski off of the snow before swinging it back into position for gliding–a motion that activates the dorsiflexors. But these anterior compartment muscles, especially tibialis anterior, are also ankle stabilizers. When we balance on one leg, the tibialis anterior is co-contracting with the soleus and gastrocnemius to maintain stability. So, it is also very busy during the glide phase so it is getting very little rest. In contrast, with classic technique the kick ski stays mostly on the snow and is brought forward action at the hip vs ankle. Meanwhile, the glide phase balance demand is generally lower.

Too much tibialis anterior? That was the finding of this study that looked at muscle activation during skate skiing. In comparing elite skiers with CECS to their asymptomatic teammates, they saw greater tibialis anterior muscle activation in the swing phase (active dorsiflexion) but even more so in the glide phase (dynamic balance). 

The swing vs glide question was also inadvertently investigated in this novel study from way back in 1992 when skate technique was emerging. And, unfortunately, so too was CECS. The authors measured intra-compartment pressures after subjects skated with both skate and classic skis. While they found slightly higher pressures with classic skis, the results were not deemed statistically significant. This would seem to demonstrate that the increased load on the dorsiflexors from swinging a longer, heavier ski did not make much difference.

The Takeaways

CECS is common enough amongst at least competitive cross-country skiers that it should not be considered an outlier diagnosis when a skier complains of lower leg pain. 

Diagnosis can be tricky, and often misleading, but relatively clear with intra-compartment pressure testing. (Clinical interjection: The testing must be done with the offending sport/activity to be accurate. Most physicians will be accustomed to patients who are symptomatic with running so the common test is running on treadmill. If a skier is only symptomatic with skate skiing, a running test is likely to return a false negative. They need to reproduce their symptoms; therefore, they need to skate ski/roller ski for the test.)

Anterior > lateral > posterior compartments. Skate > classic. Maybe symptomatic with other exercise and training but maybe not.

According to the current research, those who meet the compartment pressure criteria will likely be unsuccessful with conservative treatment and ultimately require surgery, though it should be expected that most surgeons will want to see a failed trial of PT before they operate. However, there are some tactics, from taping to training modifications, that might help to at least decrease symptoms and are very much worth exploring, especially in the short term if trying to salvage a competitive season.

The glide phase is likely the most problematic. This would seem to indicate a technique and balance issue. This is also where those of us who do not wield scalpels might make a difference in both prevention and treatment (even if the skier has had surgery). I, for one, consider the ability to demonstrate appropriate balance in ski-specific postures a prerequisite for effective skiing and recommend single leg stability exercises to all skiers, independent of CECS treatment. To paraphrase a recent interview with Matt Whitcomb, head coach of the US Ski Team: “[A]ll great technique starts with the ability to use our feet well. And for anyone that has a hard time being stable on their feet, it’s going to be very difficult to ski well in the rest of the body.” If technique changes can improve symptoms in runners with CECS, as noted above, perhaps the potential exists for skiers as well.

Ultimately, CECS is complex and often quite pernicious. Neither surgeon nor physical therapist has a magic sword to slay the dragon. However, if athletes, coaches, and medical providers work together as a team, they look to have a much better chance of taming it. 

I grew up playing soccer. Every practice was hard. “No pain, no gain,” and all of that. By tenth grade, I was burned out and quit. 

I started rock climbing. Every day at the crag was about pushing your limits. This was before indoor gyms or any concept of training other than doing as many pull ups as possible. I plateaued, got frustrated, and quit. 

Then I had a go at running. I read some books, but skipped the training methodology parts and cherry picked the workouts. Every run was hard. Every interval was done to exhaustion. I plateaued, got frustrated, and quit. 

Then I got into cycling. I began to hear of “easy” rides. I knew pros who rode around for four or five hours at such a pedestrian pace that they were talking the whole time. ‘How insanely boring!’ I thought. ‘Where’s the fun in that?’ So I went hard every time because it’s more fun. And guess what? I plateaued, got frustrated, and quit.

Fortunately, I didn’t learn my lessons the really hard way – through injury – but I still learned them the really stupid way –  by throwing away any potential I might have had. 

You can’t go hard all of the time. It’s as simple as that (at least on paper).

The Basics of Polarized Training

Make your easy days easy and your hard days hard. 

That is the backbone of a Polarized Training model. I had no problem making my hard days hard–they were all hard days after all. Full gas. Gun to tape. But in hindsight, I realize how depleted and chronically fatigued I was. I thought that was the desired effect, but it meant my training became less and less productive. 

It’s the easy days that are actually the hard part.

First: I hear your inner dialogue. “Who wants to go easy? It’s unproductive. It’s a waste of precious time. It looks lame on Strava.” But the science says everyone should want to go easy. Metabolic efficiency is the name of the game.

If hard workouts train the engine to create more horsepower, then the easy sessions improve the gas mileage. 

Secondly: let’s define easy. Training intensity is commonly split into five zones. (Some systems use three and others use seven, but I’ll be referring to a five zone system.) Zones 1, and especially 2, define the ranges of easy. Heart rate is the typical metric, especially for cross country skiers and runners, while cyclists typically use power. 

Identifying Your Easy Zones

The theoretically simple method for establishing heart rate zones is to work backwards from your maximum heart rate where each zone represents a percentage of the max. The challenge is that there’s very little agreement on how to best calculate one’s max heart rate without actually experiencing it. 

A more accurate method is to undergo a lactate threshold test, where heart rate zones are calculated based on the amount of lactate measured in the bloodstream. More accurate, but more difficult to conduct, and not universally accessible.

So how can we determine what is easy and what is too hard? 

In an effort to keep easy easy, I’m going to define it as conversational pace. You should be able to talk in complete sentences without having to… pause… to take in… more air… to finish your sentence. This is mediocre science and not especially objective, but with some practice, it’s not difficult to find that upper limit of talkability. 

If you’re a numbers person, you can likely conduct your own ramp test where – after a warm up period – you progressively increase speed/effort while reciting poetry or singing along to what’s in your AirPods. Mark the heart rate where you lose the rhythm, and that’s a decent estimate of your upper limit for Zone 2.

Your new goal on easy days will be to keep your heart rate below this threshold, not necessarily at this level. For those accustomed to pushing the pace on every session, slowing down enough to keep your heart rate in the appropriate zones might feel like a big adjustment. There’s no real way around it – you’ll need to buy in, and trust the process/science. Maybe use it as an excuse to get out with a training buddy who is generally slower than you and give the whole “pedestrian pace, talking the whole time” thing a go.

Worst comes to worst, you give it an honest try and decide you prefer to just go hammer, then go back to your old ways. That’s the beauty of being a recreational athlete – at the end of the day, we’re just pursuing hobbies we find rewarding and enjoyable. 

* A note for Strava users: don’t rely too much on the Relative Effort number. As a metric of intensity over time, it seems optimized to capture long, hard efforts like an hour-long tempo run where your heart rate stays high for the entire hour. It doesn’t handle intervals very well since the rest periods sort of cancel out the high intensity efforts. 

For example, Strava gave 60 points to a 55 minute tempo run with an average heart rate of 158; however, an 57 minute interval session (9x600m on the track) with an average heart rate of 147 only got 35 points. To me, both sessions were equally hard, but the tempo run scored 25 points higher. 

Strava does allow you to use your perceived exertion in place of heart rate for calculating Relative Effort. When I enabled this override, the tempo run scored an 87 while the track workout got a 147. (My easy efforts aren’t affected much.) Personally, I’ve found the Relative Effort score, along with the weekly log and Fitness and Freshness, far more useful (and accurate?) with this tweak. Here’s a deeper dive into that black hole.

The Purpose of Polarized Training

Now we can talk about why the easy is important. 

Stress + rest = growth/adaptation/strength/speed. That is the basic formula. Our bodies are designed to adapt to load, but we have to give ourselves the opportunity to make those adaptations. Too much volume or intensity and the body will stop absorbing. Not enough recovery and the body will stop adapting. Best case, your performance plateaus. Worst case, you get injured. 

The Krebs Cycle. The stuff of High School nightmares. But the essence of the endurance athlete. The Krebs Cycle is the pathway by which our bodies put gas in the tank. It is the process by which our mitochondria – magical little intracellular thingies – convert carbohydrates, fats, and proteins into the specific energy required by muscles to contract. In oversimplified terms, the more efficient the mitochondria are, the faster and longer we can go. And it appears that the best way to train mitochondrial efficiency is with training in Zone 2. (If you want to seriously nerd out, this podcast with Dr Iñigo San Millán, perhaps the Father of Zone 2,  is a deep dive in a submarine to depths of the ocean.)

The easy/Zone 2 is considered so important that it typically makes up 70-80% of elite athletes’ training volume. The other 20-30% is hard (high Zone 3, Zone 4, and rarely into Zone 5). For the athlete who doesn’t have all day, every day to train, that means you only get a couple of hard sessions per week. Keep the rest easy.

Some that’s hard, lots that’s easy – that’s the essence of putting Polarized Training into practice.

Example Training Plan Template

My training template is based on my work schedule and typical life obligations. I’ve given myself a max of three hard sessions a week with one of them longer (2-3 hrs ride or mountain run–the fun stuff!) and the others around an hour of intervals. My strength/core maintenance sessions typically fall into the easy category and don’t require much recovery (no delayed onset muscle soreness). But my schedule is also very flexible. If I’m tired, I can move a hard session to another day or skip it that week. If I get too busy or stressed, then I can modify the program without too much frustration.

I’m fortunate that I can train/play seven days a week, as long as I’m recovering adequately. However if your schedule only allows for training three days a week, you can still apply the basic formula and have one hard day and two easy days.

For some of you, this may be common sense and describe how you’ve been training for years. For others, this is quite a departure from your norm and will take a concerted effort to implement. But whether your goal is optimal performance or staying healthy for years to come, investing in a polarized plan, and especially leaning into the Zone 2 work, will pay dividends.

Lastly, I think any discussion about training principles/plans needs to have the overriding theme of ‘push yourself, but be kind to yourself’.

Be flexible. Training plans aren’t written in stone. Don’t beat yourself up if work, family, weather, fatigue, or lack of motivation keeps you from your intended workout. Take a walk, play with the kids, lie down on the sofa—whatever it takes to reset and be ready for another day. One workout will not make or break, but constant self-criticism will sink the ship.

My legs and lungs get plenty of work all summer from running, cycling, and strength training, but my typical dryland routine does little for the arms. I’ve tried to swim, but I haven’t progressed past drinking half the pool. 

A few years ago, I set up some resistance bands to train the arms for double poling. After developing triceps tendinopathy, taking a snapped band to the crotch, and generally finding the bands to be either too hard or too easy, I realized my workouts were far from ideal. 

What the bands gain from their price-point, they yield in utility. By their nature, the more you stretch a band, the more resistance it provides. This is the opposite of what happens with poling on snow, where the greatest resistance (or force requirement) takes place near the beginning of the pushing phase and decreases through the end of each cycle. 

Staring in the face of another hot (and smoky) summer, I splurged on a Concept2 SkiErg last spring. Thus, I was immediately able to avoid rollerskiing (without feeling guilty) while simultaneously shielding myself from the heat and poor air quality. Solved were the resistance bands’ problems of poor adjustability and inverse force curve. This utility continued during the purgatory of shoulder season in the fall, and carried me through the local trails’ annual mid-season melt out here in Salt Lake City. 

Cool tool. What do I do with it?

For some expert information, I asked Miles Havlick, head Nordic coach for the reigning NCAA national champion University of Utah Ski Team, some questions about how they incorporate the SkiErg into their training. 

What are your typical resistance settings? What’s the max you’ll use?

We almost always use the max resistance setting of 10 during SkiErg workouts. The majority of the time we do sprint type workouts on the SkiErg machines with interval lengths of less than 5-minutes in duration. However, during longer sessions we will lower the resistance in order to keep the intensity lower.

Author’s comment: 10 is hard! Keep in mind these are elite skiers. In a video blog from Jens Burman, he notes that his max resistance is 7. 

Better for easy, Z1-2 endurance or higher intensity intervals?

In my opinion, it is better for high intensity sessions targeting more anaerobic or strength training. Although the muscles are fairly similar to actually double poling, we prefer to perform longer L1 sessions on rollerskis which offers more variety in terrain and more closely resembles double poling on snow.

Author’s comment: In my opinion, pavement hurts more than snow and I haven’t lost any skin to L1 sessions on the SkiErg.

Do you cue or work on technique during SkiErg sessions?

We certainly do. It is easy to get higher power numbers when using techniques that are not as effective on snow, however, we are training to be better on snow. Therefore, we are always trying to emulate the most effective on-snow double pole technique on the SkiErg machines.

Author’s comment: more on this below.

Do you incorporate drills like balancing on one leg or BOSU?

We have played around with it but we do not regularly utilize this. It is effective for making L1 workouts more interesting, however during higher intensity bouts, it seems to detract from the quality and focus of the on-snow movements that we are trying to emulate.

Training sessions on the SkiErg can cover both ends of polarized training with the capacity for both longer duration, low intensity workouts with emphasis on metabolic efficiency and for shorter, high intensity intervals to work power. 

SkiErg Technique

While perhaps the best indoor replacement, pulling on the SkiErg is definitely not the same as poling on snow or rollerskis. The notable difference is the lack of balance with a forward trunk lean. Without bindings and the ski to counterbalance, there is much more tendency to fall forward on your face. Or, perhaps, more tendency to sit back so you don’t fall on your face. This is a likely reason why coaches can be critical of spending too much time on a SkiErg, with a nod toward the potential non-ski-specific movements Havlick alluded to when he commented that they are always attentive to form.  

With that in mind, there are absolutely some technique fundamentals that can be reinforced on the SkiErg. 

The Arms

The monotony repetition of the poling motion creates a great opportunity to reinforce some key components:

• Hands high: don’t be lazy, get those hands up
• Elbows fairly fixed with short swings under higher resistance (think uphill double pole or V1)
• Elbows extend with long swings under lower resistance (think fast V2 or V2 alternate)
• Smooth on the power: like starting a car from a dead stop but getting up to speed quickly – if you just stomp on it, the wheels will spin. With poling, we want to achieve peak force quickly but smoothly; setting the poles, then delivering power to them as the upper body drops powerfully onto the poles and the pole angle decreases to deliver the force behind the skier as a push off, versus just stabbing the poles as hard as we can into snow. The latter strategy does not propel forward motion as the peak force is directed into the ground, which incurs vibrational losses in the pole shaft, and robs the system of energy before the pole angle changes toward one more effective for force delivery. 

The Hips

“Hips high” might be one of the more overused and less understood cues in Nordic skiing. Without digging too deeply here, the basic premise while on the SkiErg is starting the poling motion from a tall position. As the body compresses with the arm pull, hinge at the hips and ankles. Then, focus on quickly getting back to the tall start position by extending the hips via contraction of the glutes (aka “squeeze your butt cheeks”). Your knees should be relaxed and bend slightly on each cycle, but you’ll want to avoid significant knee bending as it likely indicates that you are sitting back too much. I’ve personally found that one of the biggest gains I’ve found on snow is through focusing on quickly returning to the high hands and hips start position, over and over and over on the Erg.

As much as high intensity double poling is a full body effort (not just the arms), in skiing it is more about movement across the hips and ankles vs the knees. In CrossFit gyms, this is not necessarily the case. They are after maximum generation of force, not skiing efficiently. Please don’t do this.

Balance

While Havlick mentioned that they rarely incorporate balance drills into SkiErg sessions, I think they can be very useful for reinforcing single leg stability, especially if there is a specific component to address like foot pressure distribution, ankle dorsiflexion, or lateral weight shifts from the hips. As with any balance exercise, it is generally more beneficial to work on consistently accomplishing appropriate balance on the floor before moving on to an unstable surface like a BOSU or Dynadisc.

Visual learner? Here’s a helpful video on the CXC Facebook page with Eliska Albrigtsen, former CXC head coach who now leads the University of Alaska Fairbanks team. 

Looking for more? Find a 2017 Wednesday Workout with Sadie Bjornsen here, featuring 30 minutes of 30/30’s on the SkiErg.

Author’s Disclosure: Concept 2, manufacturers of the SkiErg, is a sponsor of FasterSkier; however, I purchased mine at full price before I was affiliated with this fine website. In addition to the SkiErg, Abilica makes a very similar device. The Italian company Ercolina makes an upper body ergometer that has the advantage of being much more compact and portable, but it is also more expensive and very hard to find in the US.  

Click here to read an account of physical therapist Ned Dowling’s first stint overseas with the US Ski Team in March, 2020.

Holmenkollen, Norway. March 8, 2020 – Men’s 50k Classic World Cup. 33 degrees and raining. The ski jump was engulfed in clouds. Spectators were forbidden from attending the Super Bowl of cross country skiing due to the impending COVID pandemic. My first stint as a physical therapist traveling with the US Ski Team was ending in an Oslo fog.

Salt Lake City, Utah. Late March, 2020 – Buzz kill. In the week following my return from Norway, my son’s school was closed, my clinic was closed, people were fighting over toilet paper and hand sanitizer. It was the end of the world as we knew it. And we didn’t feel fine.

July 6, 2021 – I received an email from Chris Grover asking if I could travel with the ski team again in 2022. We were amidst the calm before the storm. People were getting vaccinated. COVID cases were dropping. We went on vacation. Delta had not yet jumped out from behind the grim reaper. The light at the end of the tunnel was getting brighter and brighter.

I had declined an offer to travel the previous winter. I knew I couldn’t get permission from either the boss at work or the boss at home. And I sure couldn’t tell my kid, who was still doing school remotely, “You keep up with those classes on Zoom while Daddy is off to Europe.”

But now things were looking up. By the time I’d be overseas in March, the COVID thing would be a distant memory. Hell yes! Sign me up Chris.

Summer, Fall, Winter – We all know what happened next. The light at the end of the tunnel was an oncoming train and the shit hit the fan. Lots of shit hit lots of fans. First, the Delta variant, then Omicron. Through all of that, I did my best to stay optimistic about my opportunity to work the last two weekends of World Cup races in Falun, Sweden and Tyumen, Russia. 

Falun was a bit of a known entity, or at least easily researched on the internet. The World Cup had been racing there for years. Trail maps showed a good network of tourist tracks (which is a good thing because the race course is no joke). Videos of old races on YouTube showed huge crowds, which were sorely missed at the pre-COVID Holmenkollen. 

Tyumen, the Pearl of Siberia, was going to be much more of an adventure. Much to my relief, the plan was to have a chartered flight from Stockholm to Russia. I really, really didn’t want to fly (or crash) on a commercial Russian plane. With a lot of digging and Google Translate, I could glean some information about the race venue and its environs. 

February 9, 2022 – Chris emailed me about getting a Russian visa. He told me to contact someone at the Russian Consulate in Washington: call this guy, do what he says, pay what he says, we’ll reimburse you. The next day I anxiously called Bogdan, to whom I would be entrusting my passport. “You send passport, extra photo, and $250. You complete visa application online and send password for application, so I fix your mistakes. You send postage to mail back.” I had him repeat that three or four times while I nervously scribbled notes to myself. I reminded him that I was flying to Sweden on March 6 and would very much need my passport back by then. “No problem. You get passport.”

The visa application was nerve racking. Employment history. List of all countries traveled to in the last 5 years. “Have you been trained in firearms, artillery, or nuclear warfare?”

With sweaty palms and my heart rate in L4, I mailed off my passport and hopefully everything else I was supposed to. Then I waited. 

Thursday, February 24, 2022 –  Russia invaded Ukraine. The world as we knew it ended once again. Chris texted me that the trip to Russia was canceled (the US team’s decision not to go to Russia preceded FIS’s decision to cancel the races). “Get your passport back right away.” I called Bogdan, my contact at the Russian Consulate. “We’ve had a change in plans, and I won’t be traveling to Russia. Can you please send my passport right away?” “No. I do not have your passport. Embassy has passport. I cannot get until finished with visa. But I mail it.” I could hear a toddler crying in the background. Bogdan apologized for the crying. I told him he shouldn’t have taken my call at home. He said, “Do not worry with passport. Visa will finish on Monday or Tuesday, then I mail. I call you when I mail.”

Friday, Saturday, Sunday, Monday, Tuesday – Nope. Not going to happen. I’m never going to see my passport again. They’ve all left the embassy. My passport is too low of a priority. They’re just going to be jerks and not send it back. So much for going to Sweden. COVID, war, what’s next?

9:21am, Tuesday, March 1, 2022 –  Bogdan called. “Naatan, I mail passport. You get tomorrow.”

 I thanked him profusely. And I said a little prayer. This man is living in America, raising a family in America. Yet he works for the Russian government. He is a Russian in a country that, overnight, hates Russians. I spent the last 5 days completely stressed because I didn’t have possession of a passport that would allow me to travel to Sweden for the sake of people skiing around in circles. This man, who must pay at least some attention to Western media, must have spent the last 5 days completely stressed over the safety and ultimate fate of his family and country. 

(I do not mean to discredit ski racing or initiate some existential debate. As crazy as it seemed for the World Cup, and even Olympics, to carry on through this pandemic–and now war, I know I found great benefit from the distraction that racing provided. It was a slice of normalcy and vicarious living, which was invaluable to me as so much of what I took for granted was upended. But my little problems did seem very small compared to Bogdan’s.)

Wednesday, March 2, 2022 – Scott, our friendly (seriously, he waves to everyone) neighborhood mail carrier delivered my passport. Huge sigh of relief.

SLC International Airport. Sunday, March 6, 2022 – I hugged my son, kissed my wife goodbye, and donned my N95 mask which I wore for 18hrs straight. SLC direct to Amsterdam. Enough layover to grab a bottle of Scotch at the duty-free. A packed flight to Stockholm and a 2.5 hr bus ride to Falun. Jet lagged and sleep deprived, I met up with the team as they’d just gotten off their bus from Oslo. We all stood around in LL Bean team gear and N95s awaiting instructions on where to schlep our massive duffles.

Our accommodations for the week were not at the Scandic Hotel, the FIS-provided standard lodging for all of the teams. It was decided that the hotel and its buffet meals were too COVID risky. Instead we stayed two-each in a group of camping cabins equipped with bunk beds and a small kitchen. We were on our own for breakfast and lunch. Dinners were catered by restaurateur parents of Swedish sprint star Maja Dahlqvist (the World Cup circle is pretty close knit). 

Falun, Sweden. Tuesday, March 7, 2022 – COVID testing. The team was shedding skiers and staff with positive tests. A few soldiers were left behind to wait out quarantine in an Oslo airport hotel. A couple more made it to Sweden but wouldn’t see a race bib. Anxiety was high. A positive test meant no racing, no human interaction, no trip home until the negative. One car load at a time we went to a testing center in Falun for nasal – very, very nasal  – PCR tests. 

“I think it touched my eyeball!” “I had 31 tests in China and that was the most aggressive one ever!” “Damn, that was legit!” 

Wednesday, March 8, 2022 – All tests were negative. Collective sigh of relief. With that reassurance, I finally had some customers on the physio treatment table. Thankfully, everyone’s bodies were holding up reasonably well for being that late in the season. I felt guilty for being over there without much to do, but I figure that my boredom means they don’t need me and if they don’t need me it’s because they’re healthy, which is the goal (or they don’t want me because they’re COVID paranoid – there was plenty of that too, understandably so). So, until the racing began, I didn’t have much to do besides ski every day. Poor me.

March 11-13, 2022 – Let’s go racing! My experience with the team is that they are always a great group of people to be around, but they’re even more fun with podiums. Lots of good results all around with some “first World Cup points” to some near-misses to some 5.5 lb chunks of Gruyere podium cheese. 

4:30pm, March 13, 2022 – The final race: antigen testing for entry back into the US. Again, all negative. We’re going home! That night in the bar at a Stockholm airport hotel, I finally saw some faces that’d been hidden behind N95s all week. The poor bartender had a tough time keeping up with the drink orders. Elation, exhaustion, and simple relief that they’d survived another crazy race season and were finally heading home after four months of living out of suitcases, always masked, always nervous. 

Maybe next year we can race without a pandemic or war or plague of locusts.

***

Hi Ned,

I have been dealing with bilateral Achilles tendon soreness (midsubstance, several cm proximal to insertion) since an over-zealous hill bounding session in October.  When ski season arrived in December, and the soreness persisted, I made the assumption that skate skiing would cause less irritation to the Achilles than classic skiing.  However, after recently reading about the importance of plantarflexion force during the push-off phase in skate skiing, I have been reconsidering my assumption.  Additionally, my experience over the past month has demonstrated more aggravation from skate skiing than classic skiing, even at low intensity.  Does this make sense to you?  How would you guide a skier with Achilles tendinopathy regarding selection between skate and classic skiing?

FYI, I am under the treatment of a local PT, working on stretching and eccentric ankle work

Skate skiing is more leg and balance intensive, so it doesn’t surprise me that it’s more irritating than classic. It’s a simple matter of the body being overwhelmed by the load being placed on it. Classic skiing is exhibiting less load on the Achilles, so it doesn’t elicit a pain response. The load with skating exceeds your Achilles’ threshold or comfort level so it starts yelling. Your brain interprets this as pain, which is a pretty good defense mechanism for getting us to stop doing whatever it is that’s being perceived as a threat to our survival.

The follow up question is a matter of load management. Since load is the culprit, we don’t want too much of it. However, it doesn’t need to be avoided altogether. (And from an exercise/rehab perspective, we very much want load, just in the right amount.) 

As long as the pain is 4/10 or less and subsides within a couple of hours, you are ok to proceed. This is green light territory. Yellow light is a bit more challenging to navigate. Here in Utah, a yellow light means speed up and a red light really isn’t red for the first 4-5 seconds… but it should mean proceed with caution. So if pain is 5-6/10 or is less but doesn’t subside quickly, I wouldn’t push it any further. You were ok with that activity, but I’d probably want to back it off a little. Pain that exceeds 6/10 is definitely a red light and should be an indication that you need to pack it up and go home. (Admittedly, this guidance becomes much more foggy when the pain presents after, not during, the activity.)

So balancing the volume and intensity of skating would first be a matter of fitting into the stoplight paradigm. But you can also make a lot of your outings into skiathlons: skate until the pain begins to escalate then switch to classic. Or ski most of the time on classic then switch to skate for the last few kilometers. If you’re able to skate for a full session within the green light zone, it is a good idea to have a day or two of relative recovery before your next day of skating. This recovery could be classic skiing, cycling, or strength training, as long as pain levels remain quite low. You just don’t want to be constantly irritating the tendon.

Though not specifically addressed in your query, there is the greater question of what caused the overloading of the tendons in the first place? I know the pain began after a bounding session, but was it an issue of volume or intensity, weakness, compensatory patterning, range of motion deficits, or a culmination of your training up to that point?

In diagnosing musculoskeletal issues, we deal very little in known causation and almost exclusively in correlations. We know that large and sudden increases in training volume tend to cause injury. If the quads or glutes are not doing their share of the work during forward propulsion with bounding or skate skiing, then the gastroc and soleus (and thus Achilles) will have to do more. If ankle joint mobility is restricted, the Achilles might see higher loads. If you recently switched to a running shoe with less heel drop, the Achilles will see more load.

Hopefully, you and your PT have gained some insight into the potential underlying causes. Eccentric exercises are a very valid way to address tendon irritability, but I would highly encourage an exploration of the root cause, if that hasn’t been teased out – or at least hypothesized – already.

Happy skiing,

Ned Dowling, PT

Related Reading: Building a Better Skier Part 3: Single-Limb Stability

Author’s Disclaimer: The advice given in this article is the sole opinion of the author except where other media is cited. FasterSkier and the author’s employer (University of Utah) should not be considered accountable. As with any medical advice acquired on the internet, information presented in this article should not take the place of proper examination and treatment from a licensed Physical Therapist or Physician. If symptoms are severe or worsening, please do yourself a favor and seek appropriate medical attention.

As endurance athletes, and especially as cross country skiers, we like to suffer. We enjoy a sport that takes place in the coldest months of the year and requires both strength and endurance to climb big hills and descend on skinny skis with no edges. We like to breathe hard. Most of us are in it for the suffering and the healthy dose of chemicals that our bodies release when the heart rate goes up and the muscles begin to burn. The runner’s high, an endorphin rush, pick your preferred phrasing. 

Hopefully, we’re smart enough by now to know that we can’t go hard all of the time, at least not without consequences. The really smart among us are able to listen to their bodies and know intuitively when they can step on the gas and when they need to back off. But the rest of us could probably benefit from some type of external governor besides the voices in our heads egging us on, or constantly available Strava competition taunting from inside our pocket.

If life was just eat, sleep, and train, the calculus of easy/hard or short/long might be pretty easy. But work, school, kids, relationships, global pandemics, and social media bring no shortage of life stressors. And, physiologically, these life stressors can load the body just the same as an interval session. Stress is stress, and stress takes a toll on the body. 

So, your training plan might call for a hard session, but what if work was crazy, the kid kept you up all night, and you made the mistake of reading the news headlines this morning? Is your body in the right place to make the workout productive? (Or at least not detrimental?) How do you know?

I think the honest answer is that we don’t always have an answer, but there are some metrics that can help us shape a well-informed guess. 

Since Polar introduced the first functionally useful heart rate monitor in 1984 and Garmin gave us the GPS watch in 2006, wearable training technology has evolved considerably. Current wearables can track — and thus quantify — everything from steps to sleep to intensity. I don’t dare dive into that vast sea except to highlight and discuss what metrics might be the best at answering our question, “How hard should I push myself today?”

But before we even get there, it’s worth having a quick refresher on some principles of training, exercise, and activity. Depending on your goals, Nordic skiing can be an activity that simply gets you out in nature, a tool to maintain fitness for other sports like cycling or running in the winter, or it can be a year-round focus with time on snow dichotomized into either training or racing. In any of these scenarios, the cumulative load on the body is a very important variable to manage. 

Too much load and we stop having fun, plateau or lose fitness, and begin to risk injury. Too little load and we don’t progress, but I doubt that’s an issue with the majority of us. We must also remember that the basic recipe for improving strength and fitness is load + recovery = adaptation. Or as Brad Stulberg and Steve Magness phase it, stress + rest = growth.

Our bodies respond to load by making adaptations, but if we go too hard too often, and/or take too little rest and recovery, the equation becomes out of balance. We lose out on adaptation, and thus our capacity for improvement stalls out. 

Strategies like polarization and periodization aim to apply the load/recovery equation to maximize the training adaptations and improvements. Briefly, polarized training is the division of activities into either “hard” or “easy” intensity in roughly a 20:80 ratio. There is no “moderate.” The premise being that moderate efforts are neither hard enough to stimulate adaptations nor easy enough to allow to develop aerobic pathways or for active recovery — putting in “junk miles”, as it’s often described. 

In a periodized training program, polarization is taken a step further with hard and easy sessions layered together over longer cycles (think weeks and months). A periodized training plan builds progressively toward a goal race, followed by a period of time following the event that is focused on rest and unstructured training.

During that macrocycle, the split of your weekly training might stay roughly at the 80/20 ratio, but every third or fourth week might be recovery-focused, with a lower volume than the previous weeks. This three to four week block might be called a microcycle. On average, the easy-to-hard ratio is the same, but the overall load of the week is lower, allowing the body to adapt and repair. (And you can catch up on your laundry.)

These fundamental concepts should be incorporated in any good training strategy, whether it’s a week-by-week homemade plan or a comprehensive annual program from a coach. But, just because the plan is intended to provide a roadmap for loading and resting doesn’t mean we will always get the implementation right. 

This is not the coach’s fault. It’s life’s fault. A training program is written to balance training load and frequently doesn’t account for the additional stressors of work, school, or family. Stress is stress, regardless of the source. We can’t achieve the intended balance in training if we are over-tired from traveling for work, have been chasing our kids around all day, or burned the midnight oil trying to get our work done when our kids’ school is shut down. Similarly, pushing too hard when we should be going easy leaves us over-cooked before an interval session, deeming it unproductive. But how do we gage the load our body’s have been under?

(If you read the previous paragraphs and said, “This is stupid, I just want to ski” I don’t blame you. I don’t think everyone needs a rigid or even dichotomized workout schedule. However, if all of your exercise is at a hard intensity your risk of injury is increased so you might consider rethinking your strategy. If all of your exercise is at moderate intensity, then you’re just unlikely to get faster. For a lot of people, that’s not a priority, which is perfectly fine and you shouldn’t be judged or dissuaded. Go have fun!)

There’s an old proverb in bike racing about burning matches. Everyone on the starting line starts with the same number of matches. During the race, matches are burned quickly by riding at the front, attacking, covering attacks, and just riding above one’s threshold. At the end of the race it’s often not the strongest rider who wins but the one who burns the least matches (the 2021 men’s Paris-Roubaix is a perfect example). 

We, too, start the day with a set number of matches that we’ll burn up with road rage, frustrations at work, frustrations at home, social media FOMO, and of course training. The number of matches we get each day is directly related to how rested and recovered we are heading into the day, both mentally and physically. Exactly how many matches are in the box goes back to recovery, and, once again, to our original question: “How hard should I push myself today?”

If your matches are burnt up before you head out to train, the answer might be “Not very,” regardless of what the training plan says.

One of the earlier attempts to answer this analogue question with a binary “hard or easy”, was resting heart rate. It’s a simple concept: Take your heart rate every morning for a few weeks and calculate an average. If your heart rate has increased by more than 5 beats per minute from the average, then your inventory of matches is not fully replenished. While this article won’t go deeply into the details, there is some research to indicate that resting heart rate doesn’t correlate that well with fatigue levels. This article from Marco Altini goes into significant detail on the topic. (If you follow that link, you’ll find that you’ve arrived on the last of a five part series on Heart Rate Variability. Dr Altini is one of the leading experts and innovators in the field, you may find his articles to be more robust than one you’re currently reading.)

Relative Effort, TSS, EPOC, PTE, CTL, ATL, are all metrics generated by modern wearables to quantify training load and, therefore, stress on the body. These numbers are based largely on heart rate and duration: the higher your heart rate and the longer you keep it there, the more points you score. This is certainly useful information, especially with regards to periodization and keeping track of hard vs easy training sessions; however, it only gives you one number in the load + recovery = adaptation equation. 

We still haven’t answered the question, “How hard should I push myself today?”The same device or app that gave you a training load score will likely give a number for recovery status or a time needed to recover; this evaluation is typically still based on average heart rate during training and the overall duration of the previous session(s). It does not take into account the other life stressors. Enter Heart Rate Variability (HRV).

In a nutshell, HRV is a measurement of the time between heart beats rather than the number of beats itself. More specifically, HRV looks at the inconsistency of timing between heart muscle contractions. 

Heart rate is governed by the autonomic nervous system, or the division of the nervous system that is responsible for body functions that happen automatically. This is the same part of the nervous system that controls things like temperature regulation (sweating and shivering) and digestion — bodily functions that we don’t have to consciously think about to make happen. 

The autonomic nervous system is influenced by the sympathetic nervous system — the “fight or flight” mode that upregulates the body to prepare for battle (heart rate increases, armpits get sweaty, digestion gets turned off, etc.), and by the parasympathetic nervous system, which calms the body down. Our bodies are programmed to seek homeostasis — that happy place where everything can function optimally. The sympathetic and parasympathetic systems work to maintain that balance. 

HRV attempts to quantify that balance between the parasympathetic and sympathetic systems, and thus the measurement is a gauge of how the body is down-regulating versus up-regulating — homeostasis. 

Somewhat counterintuitively, a higher HRV, which indicates more variability and less consistency in the time between heartbeats, is indicative of greater parasympathetic versus sympathetic influence on the autonomic nervous system. Looked at another way, the greater the stress on the body, the greater the influence of the sympathetic system, which decreases the variability in time between heartbeats and therefore equals lower HRV. 

These days, there are many options for recording and tracking HRV: Whoop is a 24/7 wristband with an LED sensor that measures a gazillion things, but specific to HRV, the measurement is taken every night during sleep. The Oura Ring, which is used by some members of the U.S. Cross Country Ski Team, also contains an LED sensor and records automatically during sleep. HRV4Training has an app that turns the camera and flash of your smartphone into a recording device much like a pulse oximeter. EliteHRV uses a device that goes on your finger very much like a pulse oximeter. Firstbeat, who use a proprietary ECG style sensor, were one of the first commercially available HRV trackers on the market (as mentioned in a Nordic Nation podcast with Jim Galanes and in this old article from Zach Caldwell, which also discusses HRV in all the detail you’d expect from Zach).

With all platforms, consistency in recording is key so you can recognize patterns over time. The devices that record automatically during sleep (Whoop, Oura, and Firstbeat) have the advantage in being the no-brainers as long as you’re wearing the gizmo, but they have the disadvantage of being the most expensive. Both HRV4Training and EliteHRV require you to take the recording daily at a consistent time and in a consistent way. Ideally this is first thing in the morning (I go to the bathroom first then immediately sit down and record). I’m a creature of habit and since building this into my morning routine, I’ve not had much trouble incorporating the one minute it takes to record a daily HRV measurement. If consistency is going to be a challenge, invest in one of the automated devices.

This brings us to the utility of HRV: tracking the body’s response to stress over time. The emphasis here is over time. HRV can help answer our question, “How hard should I push myself today?”, but it’s not exactly a stoplight. Waking up to a low score doesn’t necessarily mean you should go easy if you still feel good, but waking up to a seven day average with a negative trend means you should probably skip the hard workouts until your HRV stabilizes. For example, both this paper and this paper found benefits to using HRV to modify training vs strictly following a periodized schedule.

From what we know about the metric so far, the primary goal is to keep HRV stable. If your training plan is appropriately balanced, you’re keeping life stressors in check, and your body is responding favorably, then HRV will remain fairly uniform, even after a hard workout. (A low HRV score after a hard session is definitely not a goal or badge of honor.) But if your HRV becomes unstable, especially a downward trend over at least a few days, that is when it really has the potential to catch an issue while it’s small, whether that’s due to training load, illness, or life stressors. Anecdotally, I’ve heard of notable dips in HRV with people just prior to illness (especially COVID) and after the vaccine. These are situations where maybe you’ve not yet become symptomatic — your body hasn’t started yelling at you — but it is already enduring stress, and the additional load from hard training is not going to be welcomed.

Ultimately, HRV is just another tool in the box. It’s not necessarily there to change what you do on any given day, at least not without subjective input on sleep quality, soreness, emotional state, and how much you drank last night. It’s best viewed as a safety device like anti-lock brakes on your car: if you’re always looking down the road and anticipating what’s to come, you might never need them. But sometimes, when we’re training hard and emotionally invested in our goals, it’s like driving through a snowstorm to make it home for Christmas. It can be easy to focus on the objective outcome and wanting to get there as quickly as possible, rather than slowing down and proactively adapting to the road conditions. Chances are, you’ll make it to your destination unscathed, but in the event that a deer runs across the road or you hit a patch of black ice coming into an intersection, the antilock brakes might help you stop and reset rather than crash.

As Jason Cork, World Cup Coach for the US XC Ski Team, put it, “I think it has some utility as long as you’re honestly also taking into account how you feel, how long you slept, energy, etc. I guess an analogy is if your HR at L3 is usually 180, and you’re super tired, it might be incredibly easy to hit 180 at an L1 velocity or incredibly difficult [to hit all-out velocity because HR is suppressed]. But the question really should be, ‘If you’re tired, why are you doing intensity?’”

Author’s disclaimer: I have no affiliation with any company that tracks HRV. I personally use the HRV4Training app, a Suunto watch, a Wahoo chest strap, and Strava, all of which I have paid for without discount.

This article builds upon the four-part “Building a Better Skier” series, which explores how biomechanics and movement patterns affect skiing technique, and more importantly how you can apply these concepts to improve your skiing. Please feel free to email the author with any questions: ned.dowling@hsc.utah.edu.

Recently, I overheard one of my Physical Therapy colleagues tell a patient, “We’ve got to get you jumping. If you want to get back to running, you’ll need to do some jumping first. Running is nothing but jumping from one leg to the other.” Running is a bit more complex than that, but she made a good point. 

I’d think it obvious to most that jumping is a faster, more explosive movement than simply taking a step. The same goes for running versus walking. Time spent with one foot on the ground in running is about 0.215 seconds while walking is closer to 0.6 seconds. In the context of cross country skiing, the propulsive phase during skate V2 is around 0.310 seconds and 0.230 seconds with diagonal stride. While these numbers are variable based on velocity, it should be easy to appreciate that the actions involved in running and Nordic skiing happen at a much faster rate than with walking. 

But what does ‘happen at a faster rate’ mean? To answer this, I’m going to take a dive into some physics and biomechanics. First, we need a name for what exactly is happening faster. For the sake of this article, we’re going to go with force. This is perhaps more appropriate than power and maybe less accurate than impulse, but it certainly does the trick of conveying the message that an action has been initiated with the intent of creating motion, be it skiing, running, walking, jumping, etc. (If you want a deeper dive, I highly recommend Force: the Biomechanics of Training by Dan Cleather.)

To overcome gravity and the friction (or suction) of snow, force is required. Our velocity or speed is largely dependent on the magnitude of the force we generate. However, force is not simply an instantaneous measurement. We can talk about peak force or average force, but these miss the big picture. With skiing, whether we are talking about legs propelling skis or arms pushing on poles, force can be plotted on a graph where the Y-axis is the magnitude of force, the X-axis is the amount of time that force is applied, and the area under the resulting curve is the total quantity force applied to the ski or pole during one cycle.

In this graph, the peak force (y-axis) is much greater for the blue line. The greater magnitude of force is also held for a longer period of time (x-axis). Thus, the area underneath the blue line is considerably greater than the area under the red line. All else being equal, the skier producing the blue line will be faster.

Here we see similar peak forces (y-axis), but the red line doesn’t maintain its force and drops off more rapidly (x-axis). The area under the blue line is larger as a result.

In this graph, the red and blue lines have very similar peak forces (y-axis) and duration (x-axis). However, there is a major difference in how they get there. The red line reaches its peak force faster. As a result, the area under the red line is larger than the blue. This is because, even though peak force and duration are the same, the red athlete’s peak force happened faster.

Here’s another example of similar peak force, but the blue line has a much steeper curve and is reaching peak force more quickly.

The slope of the line, “rise over run” if you remember way back to middle school, represents how quickly force is generated. This is called the rate of force development (RFD), and since it is the name of the article and we’ve spent so much time just getting to this point, it must be important.  

I already pointed out that force development in powerful skiing happens quickly. In their article, General strength and kinetics: fundamental to sprinting faster in cross country skiing (also cited above), the authors set out to draw correlations between biomechanics, kinematics, and strength in elite skiers. Among their primary findings were: 1. “Analysis of kinetics and kinematics revealed that it was not exclusively the magnitude of applied forces during skiing, but the timing and proper instant of force application were major factors discriminating between faster and slower skiers.” And 2. “General strength and power per se seem not to be major determinants of performance in elite skiers, whereas coordination of these capacities within the different and complex skiing movements seems to be the discriminating factor.” 

A primary takeaway is that RFD is related to maximum velocity. This sounds intuitive enough: a sprinter on the track is generating more force per stride over 100 meters than a distance runner racing the 5k. But they go on to conclude that as the skiers increased their speed, they decreased their stride time/duration of force (X-axis). How can speed be increasing if the duration of force is decreasing? Won’t the area of the graph get smaller? 

Some of the speed increase is the result of higher peak forces, but it was also attributed to increased RFD. If we manipulate the graph such that peak force is achieved more quickly — meaning a steep spike at the onset of the force — we can afford to decrease the force more rapidly while still generating a larger area under the curve. 

With regards to physical attributes, the authors discovered that maximum strength was not correlated with maximum skiing speed; however, jump height (aka RFD) was closely correlated. In the study, maximum strength was considered isometrically, meaning that the muscles were resiting a static load (think planks) versus a push or pull against a load. 

It also should be noted that a quicker, but shorter, stride must be accompanied by a faster stride cycle or cadence in order to be effective. This will be well understood by anyone who rides a bike with a power meter: if you are trying to maintain 300w on a climb and shift into an easier gear, your cadence has to increase or the power will drop off. The change in gearing creates less max force through the pedals but is compensated by increasing the speed at which the crank is turned.

RFD sounds awesome. How do I get some?

Simply put, you train it. In order to increase the speed at which muscles contract and generate force, we must increase the speed of muscle contractions in training. On the low-load end of the spectrum, this can mean simply speeding up standard strength exercises like squats, leg press, and lat pulls. 

At the higher end of the spectrum are jumping and plyometric training. Plyometric training significantly improves vertical jump height, which was already noted to be correlated with increased skiing speed. 

Plyometric exercises incorporate a pre-load or “stretch” phase prior to a rapid contraction. For example, if we consider a vertical jump, starting the jump from a squat position is a simple contraction of the muscles responsible for hip, knee, and ankle extension. But if the jumping motion begins in standing before dropping into a squat and quickly rebounding for the vertical jump, the same muscles that generate the jumping force are lengthened before contracting. This harnesses the energy produced by the elastic recoil of muscles and tendons. 

Think about putting a fairly tight rubber band around your wrist. The rubber band is actively contracting against your wrist and the pressure, or force, is evident. Now pull back on the rubber band and let it snap against your wrist. This amount of force is significantly and noticeably (sorry!) greater. Our muscles and tendons do not harness that much elastic energy, but you get the idea.

A pause for words of advice/caution: If the previous paragraph made your knees tremble or your back start to tighten, keep in mind that all exercises exist on a spectrum. With any exercise program, the load or difficulty must start with what is doable. There is a fine line between doing enough to stimulate adaptations in the body and doing too much, increasing the potential for injury. If you are managing a chronic musculoskeletal issue or returning from injury, it is highly recommended that you consult with a Physical Therapist or Athletic Trainer for a more personalized RFD program. Plyometric exercises can be done in a pool with a significant decrease in resistance. The overall load in the water is decreased, but the RFD benefit is retained.

Plyometric Exercises to Increase RFD:

Hopping: Whether on two feet or one, hopping drills will help strengthen the feet and ankles while developing RFD in the calf muscles. These have the lowest loads and can be valuable exercises themselves or as part of your warm up. Jumping rope falls in this category and has been shown to improve running speed.

This video demonstrates a handful of “pogo” style hopping drills. Notice how the knee and hip stay fixed with force being generated by the ankle.

Jumping: Vertical jumps, broad jumps, box jumps, drop jumps, bilateral, unilateral, backwards, sideways–the variety is only limited by your imagination. However, to get the most out of the plyometric stretch cycle, it is arguably best to make these countermovement jumps where the body drops down before exploding upwards (or sideways, forward, etc.).

In this video, Dave Quammen of Park City Sports Medicine demonstrates a series of two-legged jumping drills. Challenge can be increased with added repetitions or with reversing direction with the forward jumps. Try these on one leg for a significant increase in load/difficulty. 

Bounding: With or without poles, bounding follows the basic premise of adding “pop” to a normal stride for increased RFD and exaggerated height, distance, or speed. While boulding can be done on flat ground, there are added benefits to going uphill: because height and flight time are reduced so are the impact forces when landing. It also takes more effort to go uphill, so the workout is more efficient (more bang for the buck), and it just feels more natural.

Demonstration of more running-oriented hill bounding, from Lydiard Training.

Ski bounding with poles is a traditional dryland exercise that not only improves RFD but works the core and arms at the same time — valuable training even if you only skate ski. It can be done on a long gradual hill for endurance work, but short, steep hills will emphasize RFD.

The U.S. Ski Team completes a set of longer duration L4 ski bounding intervals way back in 2012. Camera quality has since improved, but the background song is still a classic. Note how the technique is very different from running even though the speed might be similar. 

Again, with the basic concept of creating quick, explosive movements, there are far more ways to develop RFD than this summary can hope to cover. The remaining topic, then, is dosage. 

Plyometric exercises are demanding and stressful to the musculoskeletal system. Delayed onset muscle soreness is to be expected, and at least one recovery day is mandatory. Aside from muscle soreness, any pain that is beyond mild or takes more than a couple of hours to subside should be considered a contraindication and deserving of a consultation with a sports medicine provider. 

For most readers, doing the exercises once or twice a week is an adequate stimulus for both improvement of RFD and appropriate recovery. As for duration or repetitions: when in doubt, start small. In the jumping video above, Dave demonstrates two repetitions of each jump. If we consider the full video to be one set, then starting with 2-3 sets is likely reasonable. Then, increase repetitions to progress the program. Keep in mind that quality is key — if you feel your technique or stability start to wean, it’s best to stop there. Total exhaustion is not the goal. 

Precede plyometrics with a light cardio warm up. If coupling plyometrics with core or strength training in the same session, it is generally recommended to do the plyos first before you are too fatigued.

This is Part 4 of a series delving into how biomechanics and movement patterns affect skiing technique. If you haven’t already, start with the introduction, Part 1 which introduces the concept of a neutral spine posture, Part 2 which describes spine stability and mobility, and Part 3 on single limb stability.

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Upper body power is a major contributor and perhaps even a determinant of cross country skiing performance. Poling accounts for up to 60% of propulsion in skate and classic diagonal and, obviously, 100% with double pole. For those who train for skiing year round, upper body work is an essential part of the routine. However, for those whose summers are focused on running, cycling, or hiking, arm strength is often forgotten once the snow melts.

Let’s take a closer look at the structures and muscles involved in the upper body during the various poling motions of skiing. 

The muscles that comprise the shoulder girdle can be roughly divided into two groups: the stabilizers and the movers. Coordinated motion requires “dynamic stability”, i.e., for the two groups to together such that the stabilizer muscles control extraneous joint motion while the movers perform the primary action. 

The shoulder has a tremendous amount of motion available and relies heavily on the coordinated effort of multiple muscles to maintain proper alignment and movement of the joint. At the same time, it is capable of generating large amounts of power, whether that’s throwing a 90mph fastball, hammering a nail, or repeatedly pushing on a ski pole.

The shoulder stabilizers can be further divided into those acting on the glenohumeral joint (the primary ball-and-socket shoulder joint) and those supporting the scapulothoracic joint (shoulder blade on the ribcage). 

The rotator cuff is a group of four muscles — supraspinatus, infraspinatus, teres minor, and subscapularis — that attach to both the scapula and humerus in close proximity to the joint. They are not particularly strong muscles, but they play a vital role in coordinating the movement of the glenohumeral joint. 

The only rigid or bony attachment of the arm to the body is via the collarbone. This small bone is not enough to support the load of push ups, pull ups, or double poling. The base of support truly lies in the muscular attachment of the shoulder blade to the ribcage. For the sake of the simplicity of this article, we’ll limit the discussion to four muscles, one of which doesn’t count. (Side note: a classic physical therapy trivia question is to name all 17 muscles that attach to the scapula–clearly I’m skipping a few here.) 

The primary stabilizers of the scapular are lower trapezius, middle trapezius, and serratus anterior. I’ll contend that the upper trapezius is a stabilizer but doesn’t count because it tends to exert force in the wrong direction (and is frequently overactive so needs little in the way of direct strengthening).

As with any dynamic stability in the body — abdominal muscles for the lumbar spine, glutes for the hip, or the aforementioned muscles in the shoulder girdle — strength is important but intermuscular coordination is key. This is especially true at the shoulder due to its wide range of available motion and corresponding muscular complexity. 

The following are exercises targeting the stabilizers, both at the shoulder joint and scapula.

Exercises for the Stabilizers:

(The intent of these exercises should be thought of more as activation drills and less about the heaviest weight you can find. Yes, we are looking to induce some fatigue but the emphasis is not on power.)

Side Lying External Rotation: Lie on your side. Keep the top elbow bent at 90° and against your side. Rotate about the shoulder until your forearm is at about 45° to the horizontal. Try not to pull with your shoulder blade. A little bit of weight goes a long way.

External Rotation + Uppercut: With a resistance band anchored on the opposite side, elbow fixed at 90°, and forearm against your belly. Rotate the forearm away from the belly to a neutral position (knuckles pointed forward). Then raise the arm by spinning through the shoulder. Again, the elbow should stay at 90° throughout. Only raise the arm to shoulder height. Motion should be isolated at the shoulder joint — don’t let the shoulder blade move. Finish by lowering the arm down and rotating the forearm back to the belly.

Scaption: Raise both arms up your sides at 45° (not in front, not to the side, but halfway in between). Stop at shoulder height. Keep the shoulder blades fixed down and back. Start with light weights.

Wall Slides: Loop a very light resistance band around both hands and stand facing a wall. Place both hands on the wall at about shoulder heights with elbows bent and palms facing inward. Stretch the band by squeezing your shoulder blades down and back, not just pulling from the arms. Keep the shoulder blades pinned down and back, band tensioned, and slide your hands up the wall until your elbows are at about shoulder height. Slide back down to the starting position. Ideally, the shoulder blades stay retracted throughout the set of repetitions, but you can stop and reset them between reps or as needed.

Serratus Punch: The serratus anterior muscle attaches to the ribcage, inserts on the scapula, and, acting alone, protracts the scapula, or pulls it forward. As a stand alone movement, this scapular protraction is not especially functional unless you are a boxer hitting with a jab. However, the serratus anterior is a team player and becomes very functional when co-contracting with the posterior scapular muscles (especially middle and lower trapezius) to stabilize and coordinate movement of the scapula. The exercise will work the serratus anterior independently. 

Lie on your back holding a dumbbell in each hand. Knees are bent and elbows are straight. Push the dumbbells towards the ceiling by moving the shoulder blades forward on the ribcage. This is the opposite of the motion described in Wall Slides. The neck and thoracic spine stay relaxed. This can also be done with a resistance band.

Rows: The emphasis of the rowing motion is on squeezing the shoulder blades down and back as you pull the resistance towards you. This is the same motion described in Wall Slides and the opposite of the Serratus Punch. There are multiple means of adding resistance to the movement: resistance band, cable machine, single dumbbell/kettlebell, TRX, etc. 

In the propulsive phase of poling, the prime mover at the shoulder joint is the latissimus dorsi — often referred to as the “lats”. This big, broad muscle extends the shoulder, pulling an outwardly extended arm to the side as in freestyle swim strokes and pull ups. The lats are aided by the posterior portion of the deltoid muscle and teres major. 

The elbow joint is also involved with the triceps playing a rather complex role. This muscle, or more technically speaking, this group of muscles has a common insertion on the ulna and acts to straighten the elbow. However, the long head of the triceps, attaching to the scapular vs the humerus, is also able to play a role in shoulder extension. I say the triceps play a complex role because motion about the elbow varies with technique and terrain. In Skate V1 and V2 alternate and in Classic striding, there is a fair amount of elbow extension. However, in V2 and uphill double poling, there is very little motion at the elbow. 

Notice how little motion takes place at the elbow during V2.

A clinical case study: (Disclaimer: the subject of this case is the author, a potential duplicity that is frowned upon in academia.) In the lead up to ski season, I began doing “budget SkiErg” workouts double poling with resistance bands. After several weeks of twice a week workouts, I began to develop left posterior elbow pain. It didn’t take much to figure out I had irritated the insertional tendon of the triceps. So I stopped the workouts and focused on eccentric strengthening of the triceps, which has become the standard of care in the treatment of tendinopathies. 

Come ski season, I could skate without any problems, but I continued to have elbow pain with more than about 45 minutes of classic. One night at dinner I was venting to my wife about my now chronic elbow pain. Ever the voice of reason, she asked what I would do if I was seeing myself in the clinic. What would I, the PT, do differently for a patient who is not responding? I replied that I would examine, biomechanically, how the patient is poling. So I started to think about how I was doing what I was doing. 

My hypothesis was that I was using my triceps too much to generate shoulder extension. I started doing shoulder extension exercises with my elbow fixed at 90°. I focused on leading the motion with the back of my elbow, not my hand. Within a couple of weeks, the elbow pain was gone. The lesson from my mistake is that functional movement patterns often require a high degree of coordination. Because of our bodies’ anatomical redundancy, it is easy to fall into a suboptimal pattern that is inefficient in the best case and in the worst has potential for injury.

Interestingly, the biceps appear to be very active during double poling, which seems counterintuitive since the action of the biceps is in the opposite direction of the propulsive phase of poling. The biceps do contribute to shoulder flexion so they are likely involved during the return phase. But, more likely, the majority of their action is co-contraction with the triceps to stabilize the elbow and hold it in the desired position. Perhaps this is rationale to include some biceps strengthening for more than just filling out the sleeves of your cycling jersey.

Exercises for the Movers:

Shoulder Extension: This is most easily done with a dumbbell, but a resistance band will work as well. As described in the case study, keep the elbow locked at 90° and focus on spinning at the shoulder joint by leading with the back of the elbow.

Strengthening the Triceps: Like with Rows, there are numerous ways to work the triceps with no single exercise being the best. Resistance band, cable machine, dumbbell, push ups, and dips are all appropriate.

Strengthening the Lats: The basic lat workout is pull ups. If these are too difficult to do at least 3 reps, then put your feet on a chair or on a long resistance band loop attached to the pull up bar (just make sure the band stays on your feet and not in between them!). Lat machines in the gym are a great alternative as you can select resistance that is lighter than body weight (or more than body weight if you can whip out 10+ regular pull ups)

Epilogue: The goal of the Building a Better Skier series has been to identify some key biomechanical and kinematic components of cross country skiing and to provide exercises with the specific intent of facilitating these movement patterns and strength requirements. By no means has the depth of these articles been exhaustive. Nor have the lists of exercises covered all possibilities. Hopefully, these articles have been easy to follow and the exercises have been included in your twice weekly strength/dryland/pay-to-play routine. Even better, I hope the work done now will pay dividends when the snow falls this winter. Best of luck with the remainder of summer (the heat, the smoke, the pandemic), the glorious autumn, the struggles of shoulder season, and the winter we’ve all been waiting for.

The ability to balance and be stable on one leg is where the rubber meets the road (or ski hits the snow). True, we generate propulsion with strength and endurance, but if that power is not transferred into glide, it becomes wasted effort. This is quite literally what separates the efficient from the inefficient. Or, the fast from the not so fast.

This study set out to quantify the difference in glide between elite and sub-elite skiers (national vs regional skiers). As expected, they found that the higher caliber skiers did, in fact, glide better. In trying to quantify the why, fitness aside, they found that the national level skiers had a different pattern of foot pressure in the boot. Where the regional skiers only pressured the medial side (big toe side), the national skiers loaded their feet across the whole foot. 

What’s really happening here is that the national level skiers were better at shifting their weight over the glide foot/ski. This “commitment” to the glide ski is one of the hardest things to master, especially for adults learning to Nordic skiing later in life. 

When standing on two feet, your center of gravity falls in the middle between your feet. If you want to balance on one foot, your weight has to shift. You can’t just pick up one foot. To achieve this weight shift, you can lean your trunk, which will allow you to balance, but it is not a stable or powerful position. If you shift your pelvis to the side of the stance leg, you can accomplish the requisite weight shift AND place your body in a position where muscles are engaged and ready to roll .

The skiers in this video are fine examples of appropriate, hip-centric weight shifts. Notice how the upper body stays very quiet and still. There is no side to side movement. The pelvis, however, can clearly be seen moving side to side to move the skier’s center of gravity fully over top of the glide ski.

This is all easier said than done. Go stand in front of a mirror — a bathroom vanity mirror is fine because you only need to see your shoulders. Balance on one foot. Do your shoulders stay level? Now move the opposite leg to the side and back a few times. Are your shoulders still level? If they are not, then it’s unlikely that you are shifting your weight appropriately. If you are struggling with balance on a smooth, flat floor, you can appreciate the challenge of finding stability while gliding down an undulating track on a toothpick of a ski.

Another major component of single limb stability is the coordination of joint flexion at the hip, knee, and ankle. Anyone who’s had a ski lesson has heard the phrase nose, knees, and toes —  or that the shin and trunk should be parallel. These cues are all about getting the ankle, knee, and hip to flex together. The goal is to put the body in a position that is both inherently stable due to muscle activation and preloaded for propulsion. This is what I’ll be referring to as the basic shape.

The next experiment requires a partner. Balance on one leg staying very upright with your knee and hip straight. Have your partner push you (gently!) from each side. Did you maintain your balance? Now aim for the nose, knees, toes position and have your partner push on you again. Which position was more stable? (If you had difficulty finding this position, there will be more cues with the exercises below.)

If the distribution of foot pressure and coordinated joint flexion are two major components of single leg stability — which has been shown to be a major component of skiing efficiency — then it seems highly rational that we should strive to perfect these traits on dry land before we expect ourselves to do it on skis (including and arguably even more so on rollerskis). We must be able to form the basic shape.

Adequate strength of the gluteal muscles is a prerequisite. If you don’t already incorporate glute exercises in your strength program, you can get some great ideas from previous FasterSkier articles here and here.

Foot and ankle mechanics are also a primary contributor. In the basic shape, we are asking the ankle to flex forward at the same time that the foot has to accept our full weight. Insufficient or excessive flexion, or poorly controlled mobility through the foot and/or ankle can force the tibia (shin bone) to rotate inward, taking the knee with it. Lack of glute strength and control can have the same effect from the top down. With this extraneous  motion coming from either direction, the result is an increased valgus (medially-directed) force on the knee, which equates to increased loads in both the tibiofemoral and patellofemoral joints. Clinically, this is the most common cause of knee pain with Nordic skiing.

If the prescription for controlling top-down motion is glute strength and coordination, the bottom-up is addressed through strength of the muscles in the foot and ankle. Conveniently, these can often be addressed by simply working on single limb stability — as long as you pay attention. Quality control is mandatory!

A note on orthotics: In many circles, custom orthotics have fallen out of vogue especially since studies like this one have found them to be no better than exercise at helping knee pain. But the demands on the ankle joint are quite different in Nordic skiing than with walking or running, which are more commonly studied. Skiing generally requires a much greater amount of dorsiflexion. As mentioned above, we want this dorsiflexion to happen without internally rotating the tibia. The addition of external support to the foot has the potential to control this aberrant motion. I am a strong proponent of at least some upgrade of insoles in ski boots (and cycling shoes for the same reason). Most stock insoles are terrible, even the ones that came in my very expensive carbon boots. Out-of-the-box options from Superfeet, Sole, Powerstep, and Curex are all quite good and far less expensive than custom. For some, these might not provide enough support and custom orthotics with a strategic build up of additional material would be better. 

How do you know? A quick test I do in the clinic is to have my patient balance and do a couple of single leg squats while barefoot. Then I have them do the same thing with a more supportive insole. Then I place a piece of ¼” (4mm) thick folded cardboard under the insole at the ball of the foot and have them repeat the balance and squats. I’m looking for whether they become “easier,” “less painful,” or appear better controlled to my eye. If the extra material under the insole made for improvements, then we talk about custom orthotics. If it made no difference, then I just advise an upgraded insole. Ultimately, we are looking to improve both the alignment of the knee as the ankle dorsiflexes AND improve balance.

All of that said, here are my top three exercises/drills for ski-specific balance–the basic shape. Ideally, these are done barefoot, without the additional support of an insole and shoe (opposite of the previous conversion), so the muscles have to work harder and get stronger. The basic cues are the same for all three:

• Tripod Foot: A tripod gets its stability from three legs and we want three primary pressure points on the foot–the ball of the foot, the pinky side ball of the foot, and the heel. Weight should be slightly biased forward off of the heel. The toes should be on the floor but relaxed and not gripping for dear life.
• Nose, Knees, Toes: My preferred way of thinking about this is if snot is dripping from your nose, you want it to land on your shoe not down the front of your shirt. Bend at the ankle, knee, and hip to accomplish this. 
• Weight Shift: comes from the pelvis/hip not leaning the trunk. Park yourself into the hip. If your glutes aren’t burning, you’re doing it wrong (or the exercise is too easy).
• Posture: neutral spine is the goal. Forward trunk lean occurs through the hips, not the spine.
• Forward Gaze: Avoid staring at your feet. You’ll need to keep your head up to look down the track while skiing, so best to get used to it in training. It will also remove some visual dependency and help with maintaining a neutral spine.
• Quality vs Quantity: the emphasis is on how you do the exercise, not just going through the motions. 

Start by forming the basic shape. If this is challenging to maintain, then do not progress until it becomes natural and thoughtless.

Exercise #1: Step Ups

Stand sideways on a step (preferably the bottom, not top, step). Lower your outside foot towards the floor. As you lower, you should be going into the basic shape. Return to the tall starting position. Don’t worry about trying to fully touch the floor–that’s not the goal. The goal is to move up and down, in and out of the basic shape. For added challenge, hold a dumbbell in the outside hand. 2-3 sets of 10-15 reps should be adequate to bring on some fatigue and challenge your balance.

Exercise #2: Single Leg Series with Band

Loop a long exercise band around one ankle and face the anchor point of the band. Than, assume the basic shape standing on the unbanded leg. While maintaining the basic shape, pull straight back against the band to bring the foot in line with the standing leg, then follow through to kick the foot a few inches behind. Turn your body 90 degrees in either direction and repeat the process; extending the banded leg outward to work the gluteus medius muscles of the outer hip, or pulling the banded leg toward the standing leg to stimulate the inner adductor muscles. Ultimately, you will face four different directions but the force against the band is always in direct opposition to the anchor point of the band.

If you can only source a “mini-band” loop, put it around both ankles and skip the pulling-in motion. A little resistance goes a long way with this exercise. Aim to perform 10-15 repetitions in each direction and do two laps on each leg.

Exercise #3: Lateral Hops

Form the basic shape on your right leg. Step onto the left leg, shifting your weight from the pelvis, and again form the basic shape. Progressively increase the distance between steps, turning it into more of a sideways hop than step. Keep the unloaded leg extended to the side as if skiing — do not let it flag behind the stance leg unless you are a speedskater.

Keep it honest: make sure you are sticking the landing and holding your balance for a second or two on each leg before pushing off to the next side. This is meant to be a balance exercise, not plyometric strength work. The next progression is to hold a resistance band anchored from the side. I prefer to base this exercise on time (1-2 minutes) vs repetitions so there’s no question of whether that botched one was good enough to count.

Notably absent from this article is the neurological component of balance. Many of my PT colleagues would absolutely berate me over this; however, I wanted to stick to the basic kinesiology and this article is long enough already. The brain receives massive amounts of information from vestibular, neural receptors in joints and soft tissue, and vision. In fractions of a second, it processes this information and directs muscles to act. If any link in that system is compromised, so too is your balance. If you think about the difference between skiing on a sunny, bluebird versus flat light or a storm, you can quickly appreciate how vision affects balance. There are certainly ways to challenge and train these systems, but that is beyond the scope of this article. However, an excellent way to progress any balance exercise is to do it with your eyes closed. 

This is Part 2 of a series delving into how biomechanics and movement patterns affect skiing technique. If you haven’t already, start with the introduction and Part 1, which introduces the concept of a neutral spine posture.

There are many ways to conceptualize biomechanics, but they all need a starting place. If we think about ski technique, where do we want to start? On the glide leg? With the poles? At the hips? For this series, I have opted to start with the core and work outward. I could have started with the foot and moved upward; however, I see posture as an integral part of any movement. If the posture is compromised to begin with, then that deficit permeates the activity. 

As was emphasized in Part 1, posture exists on a bandwidth of acceptability–everyone is a little different. But postures that fall outside of the bandwidth, especially when occurring within a dynamic activity like cross-country skiing, compounds load on the body. In the best case scenario, this increased load is inefficient and bleeds power. Worst case scenario, the additional load can exceed the body’s tolerance and lead to musculoskeletal injury.

And yet the spine does move. Perhaps one of the best examples is the thoracic rotation that occurs with running. The shoulders do not stay pointed straight ahead. As the right leg and left arm swing forward (with the left foot on the ground) the shoulders are going to rotate to the right. This should be a product of rotation in the thoracic spine. If the thoracic spine has limited mobility, the motion will occur elsewhere, most often in the lumbar spine which has less motion available and will likely be less tolerant of this load. A case in point may be this recent study which found that the addition of thoracic mobility exercises decreased the incidence of low back pain in cross country skiers. 

If you’re not already, sit with a neutral spine posture. Cross your arms with hands-on opposite shoulders. Rotate your body to the left and to the right. Make a mental note of how these movements felt. Now let your back flex forward in a slumping position. Try the same rotation to the left and right. I suspect they felt different. When the thoracic spine is flexed, its ability to rotate is decreased.

Use it or lose it. Our bodies are use it or lose it machines. If we do not stretch a muscle to its full length, it will tend to shorten. If we do not move a joint to its end range of motion, it will tend to stiffen. As we get older, this becomes even more pronounced. If you are of Masters age, you should probably think of stretching and mobility exercises as more about maintaining what you have versus expecting to gain flexibility. The older we get, the less pliable our bodies become. But there’s a lot to be said for maintenance.

Here are my three favorite thoracic mobility exercises – (aim to do these daily–1 or 2 minutes on the foam roll, 10x to each side with the rotation).

Foam roll thoracic extension: lie on your back with a foam roll perpendicular to your spine. Support your head with your hands. Drop your shoulders towards the floor. Pause here for a few seconds then return to your starting/neutral position. Scoot on the floor so the foam roll moves up your spine. Repeat the extension motion dropping the shoulders towards the floor. Continue this process until you have worked the length of your thoracic spine. Avoid going into the lumbar spine as the fulcrum of the foam roll tends to be too sharp. On the upper end, once the foam roll is under the shoulder blades, it’ll be tough to get much motion. This exercise can also be done with an exercise ball.

Book openings: Begin lying on your side with your knees bent and hands behind your head. Rotate your trunk like you are trying to get the top shoulder down to the floor. Pause here for a second or two and return to the starting position. This should be done on both sides.

Lower Trunk Rotation: Lie on your back with both knees bent. Cross one leg over the other. Let the legs drop towards the floor to the side of the top leg. Pause here for a few seconds and return to the starting position. Do this on both sides.

Stability could be defined as the opposite of mobility. If we are striving to maintain available mobility of the thoracic spine, perhaps it makes sense that we are striving to maintain stability at the lumbar spine. Anatomically, the body is well equipped to stabilize the lumbar spine. We have multiple layers of abdominal and back muscles that create a stable platform for the arms and legs. While the lumbar spine is lacking in rotary motion, it has quite a large range of available motion for bending forward, backward, and to the sides. Depending on the activity, this available motion needs to be either locked out like keeping a rigid trunk with skating V1 or well-controlled while bending over to put on your socks.

If we are working under the assumption that neutral spine is the ideal, then it makes sense that our core strengthening or stability work should be done in neutral spine. Traditional sit-ups that involve considerable lumbar flexion are great for building those six-pack abs that look good on Instagram, but the exercise itself only contributes to a greater tendency to over-flex the spine during activity. “Flatten your back into the floor” is a frequent cue with core exercises. While this cue, and the associated posterior pelvic tilt, is effective at recruiting abdominal muscles, it also has the effect of training the body to rely on a flexed position for muscle activation. 

Lie down on the floor with your knees bent and feet on the floor. Your lumbar spine will now be in its neutral position. If you slide a hand under your low back, your hand will likely have a bit of wiggle room between the floor and your back. This is the natural lordotic curve, and we want to maintain this during exercise (and activity). It’s easy to feel the increase in pressure on your hand when you tighten your abs and flatten your back. Conversely, if you tilt your pelvis in the other direction, arching your low back, you will have much more wiggle room. This excessive lordosis tends to be less stable since the abdominal muscles are in a lengthened, disadvantaged position for dynamic stability with much of the burden placed on the static stability of the joints.

If you had a hard time controlling movement or differentiating between the flat, neutral, and arched positions, the following exercises can be helpful to train your awareness and coordination.

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Lumbar spine proprioception

Pelvic tilts: Lie on your back with both knees bent. Start by trying to tilt your pelvis towards you. Think of trying to flatten your low back into the floor or of shortening the distance between your ribcage and pelvis. Now tilt the pelvis in the other direction like arching your back away from the floor. These motions should be isolated at the pelvis and lumbar spine–your legs shouldn’t feel like they are doing any work.

Cat/Cow: This involves the same pelvic tilt motions but without the feedback of the floor. Again, the idea is to isolate the motion at the lumbar spine not by arching the upper back.

A quick Google search for “core exercise videos” brings up over 66 million results. Clearly, we are not lacking in the number of possible exercises. But what about quality? In the treatment of chronic low back pain, there is no best exercise. From the perspectives of performance enhancement and injury prevention, while there is an argument for simply being strong, there is perhaps a better argument for incorporating exercises that help the body meet the specific demands of the activity or sport. If good ski technique demands maintenance of a relatively neutral spine, then exercises should be performed in a neutral spine. If the sport includes load through the upper extremities, like poling with skiing or weighting the handlebars with cycling, then core exercises that include weight-bearing through the arms should be included. Skate skiing places a large rotational force through the core; thus we ought to have exercises that train the body to counter-rotation. Conversely, running and classic diagonal stride involves thoracic rotation so it makes sense to train the body to perform lumbar stability and thoracic rotation simultaneously. 

Here are my Top 3, best-bang-for-the-buck-exercises in each category. Remember, the goal is to maintain neutral spine. If you are unable to control the motion, then the exercise represents too much resistance/load and needs to be regressed. These are quality-intensive exercises. A reasonable program would include 2 or 3 sets of 5 to 10 repetitions (depending on fatigue) of each exercise. Doing the routine twice a week should be adequate.

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Stability exercises: these will challenge your ability to maintain a neutral lumbar spine

Femur arc progression: Begin by lying on your back with knees and hips bent at 90°. Your back will be in its neutral position, which you are striving to maintain (there will be a little wiggle room between your low back and the floor–the amount will vary by the individual but the goal is the same). The basic femur arc is performed by lowering one foot to the floor while keeping the knee bent at 90°. The motion is isolated at the hip. There should be no motion in the low back–it will have a tendency to want to arch away from the floor as the leg goes down. Return to the starting position and repeat on the other side. Continue alternating legs. Progressions include straightening the knee as the leg lowers, lowering both legs together with bent knees, lowering both legs together with straight knees. 

Mountain Climbers: These can be done with frisbees on carpet, socks on hardwood or tile, or with a TRX. The goal is to move alternating legs back and forth with no motion in the low back. There will be a tendency to flex as you pull a leg underneath you. This should be controlled by the core but also recognize that if you are trying to pull the leg through too far, you will run out of hip range of motion and be forced to flex the spine.

Roll Out: Start on hands and knees with your hands on frisbees or a laminated placemat on the carpet, a towel on hardwood, TRX, or an old-school ab roller. The roll/slide-out motion will be a combination of shoulders and hips, but the spine stays in its neutral position.

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Anti-rotation exercises — as the title would imply, the resistance will try to twist your spine and your goal is to fight it

Plank with Shoulder Tap: From a straight arm plank with shoulders, hips, and knees in line, tap a hand to the opposite shoulder. There will be a bit of a weight shift that needs to happen to maintain stability, but this should be in the form of a side-to-side movement of the pelvis, not a rotation. This can be made easier by doing from your knees. Make it harder by substituting the shoulder tap with a dumbbell row. 

Paloff Press: The Paloff Press is a great lesson in the physics of levers. Stand using both hands to hold a resistance band or handle from the cable column weight machine. Push your hands straight out in front of you. As your arms straighten, the length of the lever increases and the resistance will exert more rotational force. Fight the twist. For more of a challenge, other than just increasing the resistance, stand with your feet together or in a lunge (with the band coming from the opposite side of the front leg).

Lunge with unilateral shoulder extension: Go into a static lunge with a resistance band in the opposite hand of the lead leg. Keeping the elbow straight, pull on the band until your hand is just past your hip. This can also be done with a cable column weight machine.

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Combination lumbar stability with thoracic rotation: simply put, the lumbar spine stays still while the thoracic spine rotates 

Seated Unilateral Row: This is a twist (sorry, bad pun) on a standard one-arm row. Sit on an exercise ball or chair facing the resistance band’s anchor. As you pull on the band, bend your elbow so your hand aims for the side of your ribcage, and rotate your chest and shoulders towards the band. Your butt should stay firmly planted and not rotate.

Lunge Rotation with Band: Stand with the resistance band coming from one side. Go into a lunge with the opposite foot forward (band from the right = left foot forward). Keep your hips pointed forward while your upper body rotates against the resistance. 

Seated Rotation (aka Russian Twist): This exercise gets a bad reputation because it’s very easy to do incorrectly, potentially placing a lot of load on the lumbar spine. It is often done in a V-sit position (like the photo but with the feet off of the floor), which is very difficult to maintain without collapsing into lumbar flexion. Add the potential to rotate through the lumbar spine and the combined motions create high loads. But we’re going to keep the lumbar spine neutral and isolate the rotation to the thoracic spine. The key points are attaining and maintaining a neutral spine while sitting with your knees bent and feet on the floor. Think about the rotation coming from the shoulders. Your belly button should stay pointed straight ahead. You can start without weight and progress to a medicine ball, dumbbell, or resistance band coming from the side. 

Notably absent in this list are exercises that target the glutes. As the primary stabilizers of the hip joint, the gluteal muscles should not be ignored in any “core” routine. However, for the sake of organizing this series, the glutes will be addressed in Part 3 on single-limb stability. If you want a head start, this Faster Skier article includes some excellent exercises. 

Building a Better Skier is a multi-part series born from the inquisitive mind of a physical therapist and late-blooming Nordic skier. (You can find the intro to the series here.) The objective is to explore how biomechanics and movement patterns affect skiing technique, and more importantly how you can apply these concepts to improve your skiing. To cover this topic thoroughly would likely require a hefty book, so apologies in advance if these articles lack depth or specificity. Please feel free to email the author with any questions: ned.dowling@hsc.utah.edu.

Posture is loosely defined as our body’s position or the way we hold ourselves. We tend to think of posture only in a static form like sitting or standing. But posture can be observed with dynamic activities like running, cycling, or skiing. Truly, we can talk about posture with anything the human body encounters. 

The primary influencers of posture are mobility and awareness. (It could be argued that strength plays a role in posture, and that is true for many sedentary people, but the readers of FasterSkier are far from sedentary.) 

The mobility or range of motion that is readily available through joints and soft tissue (muscle, tendon, ligament, and fascia) will affect our posture simply because we will always default to moving through the path of least resistance. If a joint is stiff, we will find a way to move around it. If a muscle is tight, it changes the position and efficiency of its associated joint. But also, if the ligaments around a joint have become loose like with recurrent ankle sprains, the muscles and associated tendons will have to work harder to maintain stability. Like with skiing technique, and posture in general, mobility occurs along a bandwidth. There is no single optimal measure, but there is a range that if exceeded on either end will lead to inefficiency. The old saying that everything in the body is connected is not an understatement, but it is a bit of an oversimplification. That everything in the body has the potential to affect everything else in the body might be more appropriate. 

The awareness of our body’s position in space is called proprioception. This is a broad concept that simply relates to the incoming signals the brain receives from the body so it knows how to move the body—how far, how fast, how powerfully—across multiple joints, muscles, and tendons. The brain receives this information via nerve receptors in our muscles, tendons, joints, and arguably even skin and fascia. It is what allows you to close your eyes and touch your nose without poking out your eye. Also without looking, you know that as you read this your left elbow is not fully straight and could tell us the angle of the joint with pretty good accuracy. 

So if we put the two concepts of mobility and awareness together, the former will dictate what shapes the body is capable of making and the latter will determine how accurately those shapes are made. If you are trying to make a hypothetical circle but a joint is restricted, you’ve only made an oval. If your mobility is good, but you are lacking in awareness, then you’ll be making squares or pentagons because you can’t smooth out the motion required for a circle.

While I’ve just made the case that posture is a product of the whole body, it is commonly thought of as related to the spine. As the foundation of our movements and literally the center of the body, the spine is an ideal place to start. 

The human spine itself consists of 24 vertebrae with a skull on top and ending with the sacrum and coccyx. That stack of bones is held together by countless ligaments. Between each vertebra is a disc that acts as a spacer, a shock absorber, and as a pivot point for motion. The vertebrae articulate with each other through small sliding joints located bilaterally. The orientation of these joints, which changes with the region of the spine, will determine the available motion and optimal movement pattern. Running through the center of the spine is the very precious spinal cord. Simplistically, the spinal cord is a superhighway with on and off-ramps between every vertebra. It carries information both to and from the brain. Movement and dynamic stability are provided by numerous muscles, which we will get to in more detail shortly. 

Basic anatomy having been covered, perhaps the more important implication for posture is the architecture of the spine. Contrary to the instructions to “sit up straight,” the spine, when looked at from the side, is not straight. (It’s not always straight from the front either, but the functional implications of scoliosis are beyond the scope of this article.) The spine, in fact, curves in a bit of an S from the head down in what is referred to as neutral spine. The cervical portion, comprising the 1st seven vertebrae, makes a concave curve. The next twelve vertebrae in the thoracic region have a convex curve. The last five in the lumbar are again concave. 

The appropriate amount of curve in each region is also on a bandwidth; however, the curve in one region can have profound effects on another such that they cannot be looked at in isolation. Stop reading for a moment and “sit up straight.” Now tilt your head and look up at the ceiling. Make a note of what that felt like or what you saw on the ceiling. Next slump down like a texting teenager. Look up at the ceiling again. Any difference? You probably noticed that it was much harder to look up from the slumpy position. This is because the increased flexion or convex curve of the thoracic spine changes the starting point for the extension (looking up) motion that occurs in the cervical spine. Think about how this might affect your neck when sitting on a bike. You can do the same experiment with your arms. Sit up tall and raise your arms overhead. Then repeat in a slumped position. Much easier when done in a neutral spine. 

A functional application here is how easily (and quickly) you can get your poles up to begin the next stride.

So what exactly does “good posture” or a neutral spine look like? Remember that a neutral spine occurs along a bandwidth of variability. Just as we all share the same basic anatomy, we all come in different shapes and sizes. However, the ears, shoulders, hips, knees, and ankles should generally line up while standing. Sitting is the same with a straight line connecting ears, shoulders, and hips. Again, there should be an inward curve at the low back and an outward curve through the mid to upper back. The neck will also tend to have an inward curve. 

In clinical practice, the majority of postural deviations appearing outside of bandwidth tend to fall into two categories: excessive thoracic kyphosis (to much flexion or outward curve in the upper back) or too much lumbar lordosis (excessive extension or inward curve at the low back). It is also worth noting that in clinical practice, the research would tell us that there is no evidence of “poor” posture causing musculoskeletal pain and is merely correlated with pain—not everyone who slumps all day has neck pain; not everyone with “sway back” has back pain. 

But posture that falls outside of the bandwidth creates an increased load on the body. The majority of nontraumatic musculoskeletal injuries arise as a result of an imbalance between load that is placed on the body and the body’s ability to tolerate load. So from a clinical perspective, improving posture is unlikely to be the Holy Grail, but it may be part of the solution, especially when a change in posture creates a change in pain levels.

Thoracic kyphosis tends to be an issue of mobility and/or awareness, at least in static postures. With dynamic movements, the complexity of the task may outweigh either the neuromuscular coordination or simply the requisite strength to maintain a neutral spine. Both of these scenarios will be discussed further in the next article. 

Excessive lumbar lordosis that is observed in standing, but decreases in sitting, tends to be much more complex. A simple explanation may be that the knees are hyperextending while standing. This has a simple solution: Stop hyperextending your knees! But this is way easier said than done. 

This is a pattern that has developed over years and is a tough habit to break. A much more complex pattern is one of relatively tight hip flexors along with relatively weak glutes and hamstrings. This effectively tilts the pelvis forward thereby increasing the curve in the lumbar spine. Again, this scenario might not be an issue with static posture but will be exacerbated by activities requiring hip extension such as running and skiing. This will also be covered further in the next section. 

Sitting is the new smoking. If you spend long hours sitting in front of a computer, STOP! Not your job, but the prolonged sitting. Height adjustable desks have become much less expensive and allow you to move frequently between sitting and standing. My typical advice is to change positions every 20-30 minutes. Standing is likely better, but put in one position too long and we’ll still get lazy with posture. If you don’t have this option, getting up and moving every hour can help. 

With both sitting and standing at the computer, keep your elbows at your sides and bent 90 degrees or a little less. When sitting, keep your pelvis vertical and all the way back in the chair. You should be on your sit bones. If you roll back onto your tailbone, it’s all over. The pelvis needs to remain vertical (or horizontal from front to back) in order to maintain a neutral spine. A lumbar support, or even a folded towel, placed in the small of the back will make it easier to maintain this position.

Maintenance of neutral spine with dynamic activities is no different, just harder. Again, posture falling outside of bandwidth equates to increased load which equates to inefficiency. Cycling is the easiest, at least conceptually, to transfer the ideals of sitting posture. It just requires tilting the pelvis forward on the saddle. “Bellybutton to the top tube.” Bike fit and hip mobility will both have a significant impact on how comfortably this can be accomplished. 

Running, swimming, and classic skiing get more complex due to the inherent rotation involved; however, a neutral spine as observed from the side remains ideal. A full discussion of form and technique for these sports, excepting Nordic skiing, is well outside the scope of these articles. It should also be noted that the human spine is fully capable of motion in all planes. It should not be inferred that the spine should be forever fixed in neutral. 

Stay tuned for the next part of this series which will dig deeper into spine mobility, stability, and proprioception.

Cross country skiing is hard. Very hard. Not only does it require a well-tuned cardiovascular engine, but technique can make the difference between a Ferrari and a Ford. Whether you’re a podium contender, looking to get some off-season training, or simply schussing about, we are all looking to propel ourselves efficiently. 

Technique in any sport exists on a bandwidth. Everyone skis a little differently, just like everyone runs or swings a tennis racquet in their own personal style. If the technique falls within the bandwidth, where it is accurate, powerful, and efficient, then all is good. But when it falls outside of the acceptable range, the cost becomes prohibitive. From a performance perspective, this means bleeding power. From an injury prevention side, this equates to increased load on the system

So what do we do when that efficient technique evades us? When balancing on the glide ski seems like a tightrope over the Grand Canyon? When that elbow angle never seems to satisfy your significant other? If you worked on it all winter and it still didn’t click, then it might be time to look at this technique thing a little differently. 

A while back, FasterSkier interviewed Canadian World Cup skier Katherine Stewart-Jones and her coach at the time, Erik Bråten, to discuss the apparent improvement in Katherine’s technique, which led to some of the best results of her career. Sadly, they did not disclose any magic bullets or secrets to speed. However, there was a very large pearl of wisdom:

“I took her off the skis as she could not really handle the movements I was asking her to do. And so until she was able to do that without skis, I think, it is unfair to put her on skinny skis at 30 K an hour and ask her to do it.”

When an athlete has the physical capacity to perform the technique or movement pattern but lacks the understanding or knowledge, this is called a technical deficit. This deficit often will respond to instruction, cues, and coaching. But what if one understands what is being asked but the body won’t cooperate? This is considered a mechanical issue: when a physiological deficit like balance, stability, mobility, or coordination is preventing the appropriate execution. All the cues in the world won’t help if the athlete is physically incapable of moving as desired. 

In Katherine’s case, it sounds like she had issues with both the mobility and proprioception (awareness of your body’s position and movement) of her spine. The posture she held, without the ability to correct it on her own, put her in a compromised position which led to a loss of power through her skis and poles. With the help of a physical therapist, she was able to improve these impairments in dryland training before progressing back onto the snow. With her mechanical deficits improved, she had the best race results of her professional career.

I am not a coach or ski instructor and as a significant other I try to keep my mouth shut. I am not here to offer yet another “Hips High!” cue to overcome a technical deficit. As a physical therapist who loses sleep at night analyzing Nordic skiing biomechanics, I strive to help the readers (and my patients) overcome mechanical deficits. In what will be a series of conversions on the topic, Part 1 will be a deeper discussion about posture. Part 2 will go into more detail about the spine, when to move it, and when to keep it still. Part 3 will delve into single-limb stability for both glide and kick. Part 4 will offer advice on shoulder mechanics for powerful yet healthy poling.