The objective of this study was to compare the electromyographic (EMG) activity of vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis oblíquus (VLO) during wall slide squat isometric exercises at 45º (WS 45º) and at 60º (WS 60º) of knee flexion. Fifteen healthy control women and fifteen women with patellofemoral pain syndrome (PPS) participated in this study. The EMG activity was registered during WS 45º and WS 60º performed at maximal isometric voluntary contraction (MIVC) using surface differential electrodes connected to an EMG system. The EMG signals were analyzed using the root mean square (RMS) values and were normalized by MIVC obtained at 75º of knee flexion. To compare data between groups and exercises, the ANOVA-two-way and Duncan post hoc tests were applied (p < 0.05). The results demonstrated higher EMG activity for all muscles studied at WS 60º when compared to WS 45º in both control and PPS groups. There were not significant differences between muscles during WS 60º in the control group, although a higher activity of VLL in relation to VMO and VLO was observed during WS 45º in control group. For the PPS group, no statistical difference was observed between muscles during both exercises. Thus, strengthening programs using WS 60º could be more effective for healthy women; however, both exercises could be indicated for rehabilitation programs aimed at women with PPS. In addition, the absence of significant differences between muscles in PPS group verified in this study suggests that muscle unbalance could not be a predisposing factor for PPS in women.
Patellofemoral pain syndrome (PPS); Exercise; Electromyography; Physiotherapy
