Affiliations: [a] Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Kyungnam, Korea | [b] Department of Physical Therapy, Sunmoon University, Asan, Chungnam, Korea
Abstract: BACKGROUND: Squat is the most important exercise for the strengthening of the lower limb muscles. The muscle contraction speed and type affect the muscle activation, strength, and power. OBJECTIVE: This study aimed to investigate the influence of two different speeds of squat exercise on the activation and balance of the lower limb muscles. METHODS: Thirty-eight healthy adults randomly performed squat exercises at different speeds and in different ground environments, 3 times per week for 4 weeks. The participants’ lower limb muscle activation and balance ability were evaluated before and after the training. RESULTS: There was a significant difference in muscle activation between the squats in terms of speed (fast, moderate, and slow squat) (p< 0.05). After the training periods, there was a significant difference in the rectus femoris (RF) and biceps femoris (BF) of the groups that performed the fast squat (p< 0.05). There was significant difference between the pre- and post-static balance test in the group that performed fast squats on an unstable surface (p< 0.05). After the training periods, the stability index with eyes open values, which is static balance, showed a significant difference among the groups after 4 weeks (p< 0.05). The groups that performed fast squat showed a significant difference between the pre- and post-dynamic Y balance test (p< 0.05). CONCLUSIONS: For optimal performance and effect of selected squat exercises, the speed and ground environment should be taken into consideration.
