Effects of Shoulder Abduction in Opposite Directions on EMG Activity in the Abdominal Muscles during Single Leg Raising in the Supine Position on the Foam Roller in Healthy Subjects

다국어 초록 (Multilingual Abstract)

Purpose: The purpose of this study was to examine the electromyographic (EMG) activity of the abdominal muscles and to compare the activity ratios of the bilateral rectus abdominis (RA) to oblique abdominal muscles during shoulder abduction in opposite directions with single leg raising (SLR) performed in the supine position on a foam roller. Methods: Fifteen healthy subjects were recruited to the study. Each subject lay on the foam roller and performed left single leg raising with right or left shoulder $90^{\circ}$ abduction (Abd); performed in a random order. Surface EMG recordings of selected abdominal muscles (i.e., the RA, external oblique abdominis [EO], internal oblique abdominis [IO], and transverse abdominis [TrA]) were normalized to maximum voluntary isometric contraction. EO/RA and IO and TrA/RA ratios were determined with surface EMG. Data were analyzed by Independent t-test. The statistical significance level was p<0.05. Results: The results were as follows: (1) the right RA, left EO, and right IO and TrA muscle activities increased significantly at the left SLR with left Abd compared to the left SLR with right Abd (p<0.05); and (2) the ratio of right EO/RA activity increased significantly at the left SLR with right Abd compared to left Abd (p<0.05). Conclusion: These findings suggest that left SLR with left Abd on a foam roller is an appropriate exercise for activation of specific oblique abdominal muscles.