Physical Therapist, Certified Strength and Conditioning Specialist, and open ranked skier Scot Jones writes about what we do to our bodies at the beginning of every season.

A recent post on BallOfSpray forum got me thinking about an old question I asked myself every spring. "Why do I get so sore every year when I get back on the water?" When I was in undergrad my ski buddies and I typically hit the gym extremely hard from October to February. Free weights, tons of "back" exercises, pushing each other, and basically training like you can when you have no family or job to be concerned with. Despite this those first sets always caused my traps, shoulders, and upper back to feel stiff as a board for the first week of the ski year. As I learned more about muscle function in undergrad and in obtaining my Master's Degree in physical therapy I found out why this happens. This may get a bit technical (read boring) for a minute, but stick with me. A muscle works to move your body by shortening and therefore pulling its origin and insertion closer together. While this is happening there is a reciprocal inhibition, or lengthening, of the body segment's opposing muscle to allow the movement. The working units of the muscle are tiny fibers of actin and myosin that overlap and "slide" to allow the muscle to become longer or shorter. The contraction of these fibers are catagorized in 3 ways; concentric; where the fiber is shortening as the contraction is occurring, isometric where the fibers are holding a static position under load, and eccentric where the fibers are actually getting longer even though they are attempting to shorten. These fibers can only generate force in an effort to shorten. While it is simple to see that the bicep shortens as you do a curl, you may not realize that it is actually your tricep shortening/pulling as you do a cable "pushdown."

Now this may be interesting, but why do you care? Well, the muscle can generate different amounts of force depending on the type of contraction. The lowest amount of force generation occurs with a concentric contraction, more force can be generated in an isometric contraction, and the maximum amount of force a muscle can produce occurs during an eccentric contraction. Let me use the bench press as an example. The least amount of "potential" force production occurs during the upward phase from chest to the top of the lift, the next highest as you hold the bar static at the top, and the highest as you lower the bar slowly to your chest. Notice that I said "potential' force. Because the focus of the majority of our lifting focus is on the concentric phase, we normally relax and more or less allow the weight to return to the starting position with little resistance. 

Any time you overload a muscle you are going to cause soreness. This is typically called delayed onset muscle soreness (DOMS for short) and is believed to be caused by microscopic damage and swelling in the muscle. Since you can get more force from an eccentric contraction, you get the most possible fiber recruitment, and therefore the most soreness. Many of you who are gym rats are familiar with the term "negative reps." A common example of this is the bench press. Say your 1 rep max is 275 pounds. To perform negatives you would load the bar with say 300 pounds and attempt to fight the descent of the bar to your chest lowering it as slowly as possible. You of course need 1 or 2 spotters for this as it is very dangerous. In doing this you are getting the maximum possible muscle fiber recruitment and will have some truly painful DOMS.

If you have stayed with me so far we can now talk about how this relates to skiing. When slaloming we are very rarely performing a concentric muscle contraction. This is due to the nature of our sport where we are using the resistance of the boat to generate force and propel us across the water. We are typically performing isometric contractions as we resist the pull of the boat across course, and eccentric contractions as we attempt to control the handle as we move away from it in the edge change. Of course, as the pull of the boat comes on out of the turn we are frequently beaten despite our best eccentric loading.

What do you do to prepare for this? The answer is unfortunately not that much. Performing heavy eccentric lifts is a bit dangerous, especially if you are in M3 or above. They place the maximum amount of stress possible on the muscle and their tendonous connections to the bone. You can be slow and deliberate with your form returning the weight to the start position for some eccentric effect. Doing chin ups where you very slowly lower yourself would be an example for the lats. In truth, you are going to be sore anyway. Despite our best attempts nothing mimics the forces of skiing. I have two recommendations. First, start slow. My plan of action this year is for 3-5 sets of free skiing, the "lean" drill, and just playing around. I then move to a bit of mixed skiing where I may free ski down and back, then run some longer rope passes at slower than normal speed. I hope to get 8-10 sets in before my normal "cut it" nature sets in.  My second recommendation is this... enjoy it! Nothing says another season is here and summertime is coming like those tender traps on a Monday morning.
Scot Jones PT, CSCS