MUSCLE-ACTIVITY IN WEDGE, PARALLEL, AND GIANT SLALOM SKIING

Muscle activity patterns of six alpine skiers were compared during nin e runs each of wedge (W), short radius parallel (P), and giant slalom (GS) turns. Bipolar surface electrodes were placed over 12 muscle, on the right side of the body; anterior tibialis, medial gastrocnemius, v astus medialis, vastus lateralis, rectus femoris, medial hamstrings, b iceps femoris, gluteus maximus, adductors, rectus abdominis, external obliques, and erector spinae. Repeated measures ANOVA was used to test for differences in average and peak EMG amplitudes between W, P, and GS (P < 0.1). Average amplitude was significantly different between al l turning styles (W < P < GS) for four muscles (vastus lateralis, medi al hamstrings, biceps femoris, and external obliques and significantly less for W versus P or GS for four muscles (anterior tibialis, vastus medialis, rectus femoris, and rectus abdominis). The gluteus maximus was the only muscle that had significantly greater activity in W than P. Average amplitude was greater than 50% MVC for thr vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in a ll conditions; and for the anterior tibialis, medial hamstrings, and r ectus femoris in CS and P; and for the medial gastrocnemius and erecto r spinae in GS. Peak amplitude was greater than 150% maximal voluntary contraction (MVC) for the vastus medialis, vastus lateralis, biceps f emoris, gluteus maximus, and adductors in all conditions, and for the medial gastrocnemius, rectus femoris, and erector spinae in GS. This r esearch indicates that with the exception of the gluteus maximus, grea ter muscle activity is required in GS followed by P and W turns.