The Effect of Genu Varum on the Pre-activation، Muscle Activation Pattern and Time to Stabilization During the Single Leg Jump-Landing

Genu varum is one of the most common mal-alignments of lower limb associated with dysfunction. However, little attention has paid to limb alignment and muscle activities while performing sport-specific tasks in persons with genu varum. The aim of this study is to compare the Effect of Genu Varum on the Pre-activation، Muscle Activation Pattern and Time to Stabilization During the Single Leg Jump-Landing

In thiscross-sectional study, 30 athletes (15 with and 15 without genu verum) participated. Genu varum was assessed with caliper with the accuracy of 0.01 mm. The time to stabilization was measured using force plate in the jump-landing motion. The data obtained from electromyography that synchronized with the force plate and the onset of muscle activity were calculated and analyzed in MATLAB. For the statistical analysis, independent samples t-test with the significance level of p≤0.05 was used.

The results showed that the activity of the gluteus medius muscle (p=0.003) in genu varum knee is less than normal, and this difference was statistically significant. There were no significant differences in the activity of gluteus maximus, biceps femoris and semitendinosus between the two groups. In addition,no significance difference was observed in the onset of muscle activity between groups (p>0.05). Moreover،the comparison of time to stabilization in the medial- latera (p=0.003) and overall (p=0.01) in participants with genu varum knee is higher than normal participants, and this difference was significant. Yet, in the anterior-posterior direction, there was no significant difference between the two groups (p>0.05).

It seems that genu varum is influential on the biomechanics of jump-landing and it is associated with reduced activity in the gluteus medius muscles. These changes may be associated with reducing lateral stability and increased risk of injuries in the athletes.