Changes in isolation ratios of the trunk muscles during hip adduction.

[Purpose] The purpose of this study was to compare the changes in isolation ratios of the trunk muscles during hip adduction. [Subjects and Methods] In total, 15 males aged 27-35 years were recruited for the present study. Electromyography data of the external oblique, internal oblique, and erector spinae muscles were collected during hip adduction exercise. [Results] With respect to the internal oblique muscles, the isolation ratio during hip adduction was significantly higher than during no adduction. With respect to the external oblique muscles, the isolation ratio during hip adduction was significantly lower than during no adduction. [Conclusion] Therefore, hip adduction would be a proper exercise for isolated training of the internal oblique muscles, rather than the external oblique muscles, for trunk stability.