Abstract

Aim. Plyometric exercises are one of the most important exercises to improve the neuromuscular system for prevention of anterior cruciate ligament (ACL) injury, but effects of each of these plyometric exercises are not investigated separately. Also we expected that muscle activity ratios may change on different surfaces. Thus the purpose of this study is investigating the electromyography (EMG) activity of the muscles that are important in ACL injury during implementation of 4 plyometric exercises on soft and hard surfaces in order to find an appropriate exercise and surface for prevention of ACL injury. Methods. In this study 15 male athletes participated voluntarily and two-way repeated measures ANOVAs were used to investigate the muscle activity in feedforward and feedback phases of landing. Tuck jump (TJ), Single leg hop in sagittal plane (SLHSP), single leg hop in frontal plane (SLHFP) and Squat jump (SJ) were selected as the plyometric exercises and tatami, wrestling mat and ordinary rigid ground were selected as the surfaces. Results. There were no significant differences in the activity of all muscles between surfaces (P>0.05). Significant differences in biceps femoris, gluteus medius and gastrocnemius activity were identified across exercises (P<0.05). Gluteus medius in SLHFP had the most activity. SLHSP had the most activity of biceps femoris and low activity of rectus femoris and gastrocnemius was observed. Conclusion. SLHFP is the most appropriate exercise for reinforcement and improving neuromuscular system of gluteus medius and SLHSP is the most appropriate exercise to overcome quadriceps dominance and improving neuromuscular system of biceps femoris. TJ and SJ have inappropriate ratios of lower limb muscle activity. SLHSP and SLHFP could be the most proper exercises for prevention of ACL injury.