The Comparison of Myoelectric Activity of Selected Lower Limb Muscles during Three Common Quadriceps Strength Exercises Performed with Different Loads

The aim of the present study was to compare myoelectric activity of some selected lower limb muscles during squat, leg press and hack squat exercises performed with different loads. 10 male power lifters (age: 27±4.85 yrs; height: 177±5.98 cm; weight: 80±12.13 kg) participated in the study. Subjects performed all three exercises, namely, squat, leg press and hack squat at 70% and 90% of their one-repetition maximum (1RM). Surface electromyographic signals from peroneus longus, medial gastrocnemius, tibialis anterior, vastus medialis, vastus lateralis, biceps femoris, semitendinosus, adductor longus and tensor fascia muscles were recorded using ME 6000 system at a sampling frequency of 2000 HZ while performing each exercise. ANOVA with repeated measures were employed for statistical analysis (p<0.05). The results indicated a greater myoelectric activity for vastus medialis and vastus lateralis muscles during performing hack squat and the squat exercises in comparison with the leg press exercise at different loads. The hack squat machine takes the pressure off the back and hips so it can be used as a safe exercise to strengthen the quadriceps muscles. Therefore, hack squat exercise could be recommended as a suitable replacement for both squat and leg press exercises among athletes and individuals with low back pain and sport injuries.