Comparisons of The Effects of Squat and Leg ‌Press Exercises on The EMG Activity of Quadriceps Femoris Muscles During Step Descending Activity

The Squat and Leg press exercises are methods that be used for lower limb muscular reinforcement. The aim of this study was to compare the effects of open versus closed kinetic chain exercise on the EMG activity of quadriceps femoris muscles during step descending.

Twenty healthy male students of between 20 - 28 years old were divided into two equal groups’ namely as squat group and leg press group. Squat and leg press groups underwent a 12 sessions of the Squat and Leg press exercises respectively. In synchronization with the EMG system, a Vicon motion analysis system (200 Hz) was used to separate the stance and swing phases. Measurements were repeated before and after the exercise program. Statistical analyses were done by independent and paired sample T tests.

In Squat group, after the exercise training, during stance phase, the EMG activity of the left vastus medialis muscle was decreased (P=0.040) significant. In Leg press group also, the EMG activity of the right vastus medialis in swing phase and the left vastus medialis muscle in both phases was decreased after the training program (p≤0.05). Range of reduction of vastus medialis muscular activity in Leg press group was higher than that in Squat group (p=0.050).

Leg press exercise showed better outcome than the Squat for the strengthening of the vastus medialis muscle measured in step descending task. It is suggested to use Leg press exercise with abducted hip for selective strengthening of vastus medialis muscle.