Muscle activity in wedge, parallel, and giant slalom skiing

Muscle activity patterns of six alpine skiers were compared during nine runs each of wedge (W), short radius parallel (P), and giant slalom (GS) turns. Bipolar surface electrodes were placed over 12 muscles on the right side of the body: anterior tibialis, medial gastrocnemius, vastus medialis, vastus lateralis, rectus femoris, medial hamstrings, biceps 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 all turning styles (W < P < GS) for four muscles (vastus lateralis, medial 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 the vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in all conditions; and for the anterior tibialis, medial hamstrings, and rectus femoris in GS and P; and for the medial gastrocnemius and erector spinae in GS. Peak amplitude was greater than 150% maximal voluntary contraction (MVC) for the vastus medialis, vastus lateralis, biceps femoris, gluteus maximus, and adductors in all conditions, and for the medial gastrocnemius, rectus femoris, and erector spinae in GS. This research indicates that with the exception of the gluteus maximus, greater muscle activity is required in GS followed by P and W turns.