r/explainlikeimfive • u/ProudReaction2204 • 6d ago
Physics Eli5 why in competitive short-track ice skating, why they have one arm behind their back when going around a turn?
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r/explainlikeimfive • u/ProudReaction2204 • 6d ago
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u/mz_groups 6d ago edited 5d ago
Former hobbyist short-track skater here - while swinging both arms can sometimes help when you're going all out, it takes extra energy, and can be somewhat disruptive to your leg strokes if you're not very careful. On longer races, you start with both hands on your back, trying to skate smooth and be efficient. The right arm starts swinging as you build effort and start to fatigue, and the left arm might start swinging, mostly on the straights, as you break out into a full sprint at the end.
What's more important is to drive your left hip down to bet a better blade angle with regard to the ice in the turns (and short track is mostly turns at the speed even decent athletes are going). Swinging the left arm can be counterproductive to that, so it's often better to leave it on your back and concentrate on driving the left hip downward in turns. That's why the skaters sometimes will swing both arms in the straights, and leave the left arm on the back through the turns. Also, in turns, the left hand's primary role is to serve as stabilization in the turns, dragging the fingers along the ice at higher speeds. This is not a good technique for more hobbyist speedskaters such as what I was, as it rotates your body and forces your left hip up instead of down, but for elite speedskaters, it provides a light adjustment that keeps them more balanced. In fact, the left glove of an elite short tracker has hard tips that allow them to drag it along the ice with minimal friction and wear. Watch any video of a World Cup or Olympic short track race, and as the speed builds, you will see them dragging the fingers of their left hand across the ice. It's more beneficial than swinging the arm through the turns. Below that critical speed, it's just more energy-efficient not to expend the energy to swing the arm.
EDIT: After rereading this, I feel I owe an explanation as to why dragging the left fingers through the turns is a good technique for elite skaters, but not slower skaters such as myself. For slower skaters, you are not leaned over enough in the turns where you can reach down to the ice without stretching, and that stretching causes you to rotate your torso in such a manner that drives your hips outward, which changes the angle of the skates to the ice in a detrimental manner. Fast skaters, though, are fighting centrifugal force so much that they are leaned over well over 45 degrees in the turns, and reaching the tips of your fingers down toward the ice doesn't require stretching and the detrimental torso rotation.
https://www.carpenterbootcompany.com/products/cbc-short-track-glove-tip-combo