Effects of Carrying Out a Low-Intensity Isometric Contraction of the Proximal Thigh Muscles on the Electromyographic Activity of the Leg Muscles when Simulating an Ankle Sprain

Background: The patterns of activation of the leg musculature can be altered after suffering from a sprained ankle, which can contribute negatively to the biomechanics of the leg. Ankle sprains can generate changes in muscle electromyographic activity in both the thigh and ankle regions, for which physiotherapy is the most common treatment. This study aimed to determine the effect of a low-intensity isometric contraction of the proximal thigh muscles (gluteus maximus (Gmax), gluteus medius (Gmed), tensor fasciae latae (TFL) on the electromyographic response of the tibialis anterior (TA), peroneus longus (PL), lateral gastrocnemius (LG), and soleus muscles (SL) in a sudden ankle supination. Methods: Fifteen healthy volunteers were subjected to 2 series of three trials on a sudden ankle supination platform (50°). This involved a multiple analysis of variance per trial and muscle for the dependent variables and an analysis of variance in the measures repeated under study for the different time windows evaluated, according to the intended factors and muscle studied. Results: No significant differences were observed in the variables concerning the time of activation, the moment of maximum EMG registration or registered peak value. Conclusion: Inducing a low-intensity isometric contraction of the abductor leg muscles did not generate changes in the muscular values studied.