Abstract
The purpose of this study was to compare muscle activation during the squat with
different hip rotations (neutral, 15, 30, and 45° of internal and
external hip rotation) in subjects with and without Genu Varum deformity
deformity. Surface electromyography were recorded from 32 men with
(n=16) and without (n=16) Genu Varum deformity. In the Genu
Varum deformity group, the squats with 30, 45 and 15° of internal
rotations of the hip showed significantly greater gluteus medius activation as
compared to other positions. Moreover, the tensor fascia lata activity increased
with greater external rotation of the hip, and significantly more than hip
internal rotations (p<0.05). For vastus medialis and vastus lateralis,
both hip internal and external rotation showed a significantly greater
activation compared to the neutral hip positions (p<0.05). There were
significant differences in the gluteus medius:tensor fascia lata activity ratio
(p=0.001) and the vastus medialis: vastus lateralis activity ratio
(p=0.001) between the different hip positions in the Genu Varum
deformity and healthy groups. These results demonstrate that muscle activation
patterns varied significantly with the position of different hip rotation in
both groups. Those with Genu Varum deformity may use this information to aid in
an injury prevention strategy by choosing squat positioning that favorably
alters muscle activation patterns.
Key words
squat - electromyography - genu varum - hip rotation