Skiing and Snowboarding

Alpine or downhill skiing is a complex skill that requires a series of integrated movements that requires controlled pronation, setting the foot, ankle, and lower extremity on the inside ski edge. Pronation sets the inside edge of the downhill (control) ski and allows for the skier to lean inward against the ski which holds a skidless arc throughout the turn. Even today with wider parabolic skis, the skier drives the shin forward against the stiff wraparound type, or hybrid type boot cuff and swings the hips to the opposite direction. The ski rolls onto its sharp steel edge and bites the snow, creating an arc across the hill [1]. Skiing in the freestyle is like ballet dance on snow, yet at the same time, the skier encounters many centrifugal and G-forces, as turns are created, while simultaneously attempting to keep the center of gravity in line over the center of the ski. Any deviation of normal lower extremity biomechanical balance can alter the skier’s ability to carve a controlled turn, thus placing the skier at risk for injury if the biomechanical abnormality is great enough. Before a skier should consider taking part in this demanding sport, three important factors are important in a skier’s conditioning and performance, namely flexibility, strength, and adequate range of motion of lower extremity joints. A number of variable factors such as structural deformities, functional deformity, or dynamic imbalance of muscle groups can influence the performance of the skier and also help to predict potential injury. When skiers have pre-existing injuries, i.e., knee instability, quadriceps muscle weakness, posterior tibial dysfunction, chronic peroneal tenosynovitis, etc. this will contribute to muscle weakness, decreased flexibility, and limited range of motion of involved lower leg joints. This will limit the skier’s ability to ski efficiently and safely, and as a result, increase the muscular effort required, resulting in greater skier fatigue. Fatigue has been shown to be one of the main factors in the incidence of downhill skiing injuries [1], and the same effect occurs in snowboarders as well.