فاطمه سالاری اسکر

Purpose: A variation in squatting technique is using arms to actively push the bar up with the upper limbs which is common in bodybuilding. This study aimed to compare the Electromyography (EMG) activity of selected muscles during squat with and without upper limb assistance. Methods: This was a quasi-experimental study. Fifteen healthy male power lifters (using the convenience sampling method) participated in this study. Participants performed 2 sets of 5 repetitions while squatting 70% of their one-repetition maximum with and without upper limb assistance. Surface EMG signals were collected from 6 muscles using a wireless electromyography with a sampling frequency of 1200 Hz. The paired sample t test was used for statistical analyses at a significance level of P<0.05. The obtained data were analyzed using SPSS. Results: Average activity of the gluteus medius during the upward phase of squatting with upper limb assistance increased by 17.1% (P=0.017), compared to squatting without upper limb assistance. Mean activity ratio of the vastus medialis during the downward phase with upper limb assistance showed a 6% decrease (P=0.008). During the downward phase of squatting with upper limb assistance, the mean activity ratio of the vastus medialis to vastus lateralis increased by 15% (P=0.039). During the upward phase with upper limb assistance, the maximum activity of the gluteus medius increased by 22% (P=0.043). Conclusion: The activity level of the gluteus medius and the activity ratio of the vastus medialis to vastus lateralis increased as a result of squatting with upper limb assistance. This could possibly be helpful in the rehabilitation or prevention of injuries such as patellofemoral pain or iliotibial band friction syndrome. It could also have implications for training variation.