Physical Treatments (Jul 2017)
Effect of Genu Varum Deformity on Gluteus Medius Muscle Activity and Postural Control During Single-Leg Jump-Landing
Abstract
Purpose: Genu varum deformity changes the line of gravity from center of knee towards the medial side. This deviation results in changes in the upper part of the lower extremity that can affect postural control as well as the position and activity of the proximal muscles of the knee joint, like the gluteus medius muscle. Therefore this study aims to investigate the effect of genu varum disorder on the activity of gluteus medius muscle and postural control during single-leg jump-landing exercise. Methods: A total of 28 male students of Physical Education Major (Mean [SD] age, weight, and height: 21.53[1.65] y, 66.76[7.51] kg, and 173.38[4.54] cm, respectively) were enrolled and studied in two groups of genu varum (14 students) and normal ones (14 students). The activity level of gluteus medius muscle and the ground reaction force were measured using electromyography device and force plate, respectively in single-leg jump-landing exercise. In order to analyze the data, we used the Independent t test at significance level of P0.05), but the time to stabilization in the medial-lateral and in resultant vector direction in the genu varum group was significantly more than those in normal knee group (P<0.05). Conclusion: Participants with genu varum have weakness in postural stability in medial-lateral and total RV direction that might decrease the activity of gluteus medius muscle. This might increase the demand on the muscle for stabilizing hip and pelvis which decreases control of transverse and frontal part of hip and finally affects postural stability in medial-lateral direction (may be due to inappropriate activity of the hip). Thus, improvement of gluteus medius muscle might improve medial-lateral control of the posture in individuals with genu varum.
