Affiliations: [a] Department of Physical Therapy, Metro Hospital, Busan, Korea | [b] Department of Physical Therapy, Busan Orthopedics Hospital, Busan, Korea | [c] Department of Physical Therapy, College of Health and Welfare, Silla University, Busan, Korea
Correspondence:
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Corresponding author: Bo-ram Choi, Department of Physical Therapy, Silla University, Baegyang-daero 700beon-gil, Sasang-gu, Busan, Korea. Tel.: +82 51 999 5438; Fax: +82 51 999 6238; E-mail: boram@silla.ac.kr.
Abstract: BACKGROUND: When various balance exercises are combined with strengthening or stretching exercises, the specific effects of any individual balance exercise are unclear. OBJECTIVE: The purpose of this study was to compare muscle activation and ratio in the quadriceps, hamstring, and gastrocnemius muscles in balance exercises. METHODS: In total, 20 healthy volunteers participated. The balance exercises consisted of standing on one-leg stand, a lunge, and trunk rotation. Electromyography data were collected from lateral quadriceps (LQ), lateral hamstring (LH), lateral gastrocnemius (LG), medial quadriceps (MQ), medial hamstring (MH), and medial gastrocnemius (MG). One-way repeated-measures analysis of variance was used to assess the statistical significance of the muscle activation, muscle co-activation, and the muscle activation/co-activation ratio in the balance exercises. RESULTS: Compared with the other exercises, co-activation of the MQMH, LQLH, and LHLG increased significantly during the lunge (P< 0.05). During the lunge, the increase in LQLH and LHLG co-activation was significantly greater than that in MQMH and MHMG co-activation (P< 0.05). CONCLUSIONS: Co-activation of lateral muscles was greater than in the medial muscles during lunge exercises with repeated lunge exercise potentially causing lateral knee joint compression. Therefore, physical therapists and/or athletic trainers should pay specific attention to use of lunge exercise within the framework of balance exercise program.
