Electromyographic analysis of lower extremity muscle activities during modified squat exercise: Preliminary study

The squat is a movement that keeps the knee angle at 90° while keeping the weight of the one's shoulder to the shoulder width and maintaining equal weight load on the left and right legs. However, sufficient muscle activation of the lower limb is necessary to maintain a knee angle of 90 degrees. Thus, this study has been conducted to confirm the possibility that a modified squat exercise compared to traditional squat exercise can be recommended for elderly or patients. Two healthy adult males participated in this study. They performed a traditional squat exercise and a modified squat exercise. The modified squat exercise was performed in a general squat exercise posture while keeping the knee at 90 degrees and extending the hip joint with leaning the ball behind the back (supine position). The muscle activity of rectus femoris, vastus medialis, vastus lateralis, and gastrocnemius during exercises was measured by surface electromyography. As a result of this study, it was found that muscle activities were less in the right and left rectus femoris, vastus lateralis, vastus medialis during the modified squat exercise compared to the traditional squat exercise. The results showed that the muscle strength of the lower limb was activated to less than 50% compared with the traditional squat exercise during the modified squat exercise. These results may be used as an effective rehabilitation method for patients with weak muscles in the lower limb.