Skeletal muscle movements
In cross-country skiing the muscles are primarily voluntary movements. Skeletal muscles surround the bones of the body. They are connected together by tendons. Cross-country skiing engages all of the major muscle groups in the body. Coordinated movement requires muscles primarily responsible for movement (agonists), muscles that assist prime movers (synergists), and muscles that oppose prime movers (antagonists). Agonists produce most of the force needed for a movement. Synergists assist the action and fine tune the movement. The antagonist protect.
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An example of this would be the quadriceps and hamstrings. When your hamstrings(agonists) contract, your quadriceps (antagonists) oppose the motion. This prevents overstretching. |
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Main Movements The prime movers flex a limb and do the majority of the work. The antagonists are extensor muscles. The synergists steady the bone so the limbs will move in a specified direction. When lifting a ski pole forward and up the biceps contracts acting as the agonist muscle. As it does, the triceps relaxes, acting as the antagonist.When the ski pole is planted in the snow, the arm moves down and backwards. In this movement, the triceps becomes the agonist and the biceps is the antagonist. |
Types of muscle actions
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There are three types of movements associated with muscle movement. These are static, concentric, and eccentric. Static action is a non-moving position of a joint. The length of the muscle does not change. When a cross-country skier is tucked in a downhill body position, they are in a static muscle state. |
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Concentric action is a shortening of the muscle. Eccentric action lengthens the muscle. When these actions occur together, it is referred to as dynamic action.In Olympic cross-country skiing, eccentric muscle action is used immediately before concentric action. This increases the force of the muscle actions. In a correctly executed movement in cross-country skiing an eccentric movement must stretch beyond 100% and then contract immediately. An Olympic skier must perfect this movement to get greater forward acceleration and speed. |
