Comparison of Abdominal Muscle Activation Based on Hip Abduction Degree during Straight Leg Raise Exercise

Objective: The alteration in joint angle or position plays a crucial role in influencing muscle activities, given the diverse directionsof muscle fibers. This diversity leads to the hypothesis that responses to loads applied from various angles will exhibit variability. To enhance the stability of abdominal muscles, this study examines the impact of hip abduction during straight leg raising on muscular activity. Design: Repeated Measures DesignMethods: The equipment used was an electromyography measuring instrument and was attached to the dominant muscles in therectus abdominis (RA) and external oblique abdominis (EO). The experiment was conducted three times at random with adductedhip position, neutral hip position, and wide abducted hip position. At each position, the maximum pressure of the individual was kept at 50% of the maximum pressure and measured three times for 7 seconds. Results: There was a significant difference in the activity of the RA muscle according to the degree of hip joint adduction duringstraight leg raising. There was also a significant difference in the activity of the EO muscle according to the degree of hip jointadduction during straight leg raising. Conclusions: This study have shown that the muscle activity of the abdominal muscles in the hip joint, as wide as the pelvis, is thehighest, and the lowest in the hip joint adduction position. It is most effective to perform straight leg raise exercises that are stretched to the individual's pelvic width.