Electromyographic analysis of VMO and VL across straight leg raise, short arc quad, medial tibial rotation and hip adduction in normal individuals.

Abstract

The lateral malalignment of patella is considered to be the main cause of patellofemoral pain syndrome (PFPS). PFPS, in an occupational setup, is aggravated by prolonged sitting, climbing stairs, squatting, and kneeling. Strengthening of vastus medialis oblique (VMO) opposes the lateral force produced by vastus lateralis (VL) and helps in stabilizing patella. The main objective was to compare six common rehabilitation exercises (REs) and to identify those which could possibly activate VMO selectively to alleviate PFPS of occupational workers. Ten subjects, having no history of PFPS, performed six REs, namely, straight leg raise with neutral hip position (SLRN), straight leg raise with externally rotated hip position (SLRER), short arc quad with neutral hip position (SAQN), short arc quad with externally rotated hip position (SAQER), medial tibial rotation and hip adduction (HA). REs were compared on the basis of integrated electromyographic activity of VMO and VL. Results demonstrated that VMO activity was more than that of VL during all REs. However, this difference was not statistically significant in any of the six REs. HA produced significantly higher VMO activity than SLRN, SLRER and SAQN. The results provided a wider range of options for selecting apposite REs for treating patients diagnosed with PFPS.