Peroneal muscle activity during stable and unstable load exercises. A cross-sectional study.

OBJECTIVE:To evaluate the muscle activity of the peroneus longus during the execution of different unstable load exercises compared to stable load exercises. DESIGN:Cross-sectional study. SETTING:Functional Anatomy Laboratory. PARTICIPANTS:28 healthy athletes. MAIN OUTCOME MEASURES:Surface electromyography (sEMG), unstable load (water tank), Stable Load (Sandbag), type of exercise (Isometric single leg stance, single-leg Romanian deadlift, front rack forward lunge and lateral lunge). RESULTS:The repeated measures ANOVA revealed significant Group ∗ Time interaction in Root Mean Square (RMS) (F = 51.307, P < 0.001, ŋ2 = 0.70). In the between-group analysis there were statistically significant differences in RMS isometric single leg stance in favor to unstable load (P < 0.001, ŋ2 = 0.07). In the within-group analysis of RMS statistically significant differences were found in the stable load group between isometric single leg stance and single-leg Romanian deadlift (P < 0.001, ŋ2 = 0.05). CONCLUSIONS:Single leg stance exercise with unstable load showed higher peroneus muscle activity than stable load. However, no peroneus muscle activity differences were found between unstable and stable loads for single-leg Romanian deadlift, frontal rack forward lunge and lateral lunge. Single-leg Romanian deadlift with stable load showed higher peroneus muscle activity than isometric single leg stance with stable load.