Comparison of knee joint muscle's activity in subjects with genu varum and the controls during walking and running

Lower extremity deformities are associated with various dysfunctions especially during the gait. Despite the fact that genu varum is one of the most common lower extremity abnormalities, it remains unclear what influence this deformity has on one’s functional performance. This study aimed to compare the muscles activity of knee joint muscles in normal subjects and individuals with genu varum during walking and running. In this quasi experimental study, sixteen male subjects aged 15.5 ± 0.6 years were divided into two matched groups, namely, the patients with genu varum and the controls. General and directed co-contraction of knee muscles was evaluated during various phases of walking (loading response and mid stance/propulsion phases) and the stance phase of running. Compared to controls, the subjects in genu varum group displayed greater electromyographic activity of the knee muscles during the loading response phase of walking (%18) and the stance phase of running (%31), but these differences were not statistically significant (P = 0.52 and P = 0.55 respectively). Subjects in genu varum group showed a higher magnitude of directed co-activation of the lateral muscle of knee than medial muscles during the loading response phase of walking and the stance phase of running. In contrast, the control group showed higher magnitude of directed co-activation of the medial muscle of knee. These results demonstrated no significant differences between individuals with genu varum and their control counterparts in the magnitude of muscle co-activation during walking and running. But, it seems that the observed differences in the activation of selected lower extremity muscles between subjects with genu varum and the controls during walking and running may have clinical implications.