Electromygraphic Activity of the Vastus Medialis Oblique and Vastus Lateralis Muscles During Selected Exercises

Abstract

The purpose of this study was to determine if the vastus medialis oblique:vastus lateralis (VMO:VL)integrated electromyographic (IEMG) ratios differed between selected exercises. The EMG activity of the VMO and VL muscles were measured in 54 normal subjects during various exercises. Subjects ranged in age from 15–49 years (X=27.5, SD=7.01). The exercises included: 1. stationary bike (BK) 2. single leg 1/4 squat (SQ) 3. bench step (BS) 4. quad setting (QS) 5. short arc quads (SAQ) 6. straight leg raise (SLR). The results showed that there was a significant increase in the integrated EMG (IEMG) VMO:VL ratios during the BK, SQ and the BS when compared to the QS, SLR, or SAQ. There was also a significant increase in the IEMG VMO:VL ratios for the combined closed chain exercises when compared to the combined open chain exercises. These results suggested that there may be exercises that can be prescribed that are more beneficial in selectively activating the VMO. This information will assist physical therapists in prescribing the most optimal exercise for their clients.

Keywords:

• Electromyography
• Vastus Medialis
• Vastus Lateralis
• Exercise