Effect of psoas major pre-activation on electromyographic activity of the abdominal muscles and pelvic rotation during active leg raising

[Purpose] This study investigated the effect of psoas major pre-activation on the electromyographic (EMG) activity of the abdominal muscles and pelvic rotation during active leg raising (ALR). [Participants and Methods] Twenty healthy participants were enrolled. ALR was performed in a conventional manor or with contralateral psoas major (cPM) pre-activation. The EMG activity of the abdominal muscles, including the rectus abdominalis (RA), external oblique (EO), and internal oblique (IO), was measured, as was pelvic rotation. Paired t-tests were used. [Results] The EMG activity of all studied muscles was significantly increased, and pelvic rotation was significantly decreased, during ALR with psoas major pre-activation compared to the levels under conventional testing. [Conclusion] cPM pre-activation during ALR can increase abdominal muscle activity and minimize pelvic rotation.