Influence of muscular fatigue on skiing performance during parallel turns

Muscular fatigue and muscle-activation patterns during a skiing demonstration (down a coarse around 4000 m long) was evaluated. Nine subjects participated in skiing trials and pre-training with a squat exercise. Surface electromyogram (SEMG) signals from the agonist and antagonist muscles around the knee at certain knee-joint angles were recorded. The SEMG signals showed that experienced skiers maintained their posture regardless of muscle fatigue by means of sustained muscle contractions in accordance with the change in inclination of the slope. In contrast, intermediate skiers did not maintain their posture (because of muscle fatigue) and distributed their strength over muscles to co-contract with each other. It is concluded from this result that the influence of muscle fatigue on skiing performance is related to skill level.