Well there is no question about it that ski season is coming up fast. In the spirit of winter sports just around the corner I want to talk about some of the physiology that occurs. So buckle up, it’s time to do some learning!
Frist, I want to discuss is the general muscle actions of skiing. This is where we have to use our thinking caps a little bit and visualize a turn.
Research has demonstrated that eccentric leg strength is crucial for all avid skiers. Eccentric strength refers to the type of muscle contraction that occurs in the sport. Eccentric contractions is when the muscle fibers are lengthening but are still producing force. For example, when you do a Leg Blaster or Quadzilla the most prominent eccentric contraction is when you land from one of the jump lunges or jump squats.
So how does that translate to skiing? When we turn skiing the body experiences large gravitational forces (g-forces). A g-force occurs when the surface of one object or thing is pushed against a surface of another. Research has found that a skier can create as much as 8 g (Scott, 2016). What this means is that with in an instant the skier must be able to with stand 8 time as much as their body weight (i.e. 8 g x 150 lb = 1200 lb). It takes many things for the body is capable of doing this, but eccentric strength is crucial. The muscles work eccentrically as we go through each turn and with a greater amount of g-force acceleration more strength is required. Without the necessary strength your body would collapse under the amount of force.
The internal actions that occur in the body over a day of skiing are extreme and vast. This is only a fraction of what happens over a day on the slopes. It is so very important to keep your body in shape for the unexpected events of skiing. With gravity constantly accelerating you down the slope it is truly a battle of man verse nature.
I hope you guys are still with me. The next thing involves more physiology and the biochemical reactions that occur in a ski run. Without much adieu, let’s jump in.
Most of you are probably familiar with the burning sensation in your legs after skiing some long steep runs along with some heavy breathing by the end of the run.
Well there is a scientific explanation to that!
Skiing itself is a highly anaerobic sport. Studies have found that maximal oxygen uptake can range from 120% – 200% (Turbell, et al. 2009). Essentially this information means that there is a large amount of energy expenditure within a run of skiing. Most of the energy comes from our anaerobic metabolism aka Glycolysis. Glycolysis is a way that our body produces glucose (blood sugar) into energy. The process is very quick and therefore gets the body the energy it demands quickly. However, Glycolysis is primarily used in short 60 sec efforts before it transitions to our aerobic metabolism. With skiing because there are supramaximal levels of oxygen uptake the body is not able to utilize the aerobic metabolism as well. This in result is the cause of the burning sensation in the legs. When Glycolysis cannot carry on into our aerobic metabolism it creates Lactic Acid. Lactic Acid is not the real enemy though; it is the chemical properties that are associated with it. Because it is an acid there is more hydrogen in the compound. When the Lactic Acid is broken down in the blood stream it leaves behind little Hydrogen Ions floating around the muscle. These ions inhibit the muscle fiber to contract and form the cross bridging sequence.
Now the next question that you are probably asking is “How do we avoid this from happening?” In short, this will always happen but we can train our bodies to buffer these hydrogen ions more efficiently. Working at a similar intensity as skiing will simulate the same physiological chain reaction. However, asides getting the strength gains through the exercise you are also training your physiology to work more efficiently!
For those that are in ski and snowboard fitness I hope this spreads light into how or why you feel better on snow and for those that are not with us try to incorporate the science into your training regime!
It is time to get strong, stay strong, and ski strong.
Resources Turnbull, J. R., Kilding, A. E., & Keogh, J. W. L. (2009). Physiology of alpine skiing. Scandinavian Journal of Medicine & Science in Sports, 19(2), 146-155 Scott, A. (2017, June 14). Pro Skier hits 8G's, Burns 2,900 Calories in a day of Resort Skiing. Retrieved October 12, 2017, from http://mtntactical.com/research/day-professional-resort-free-skiing-physiology/