The Effect of Muscle Activation in Trunk Stabilization Exercise According to the Joint Angle of Normal Adults

The quadruped position is one of the trunk stabilization exercises. This improves the pelvic stability and muscle strength during performing the complicated movements. There was no study about the comparisons of the trunk muscle activation according to the hip joint angles. The purpose of this study was to analyze trunk muscle activity in quadruped posture according to the hip flexion angle (70°, 80°,90°). The subjects were 30 healthy young adults (15males, 15females). They performed 2 different postures of trunk stabilization exercises (with one leg raise and with contralateral arm and leg raise) in the quadruped position. The surface Electro-Myography (sEMG) was bilaterally recorded from Rectus Abdominis (RA), External Oblique (EO) and Erector Spinae (ES). As a result, the ES muscle activation(%MVIC) showed a significant difference in the quadruped position according to the hip flexion angles between 70° and 90°(p<0.5). There was no significant difference in RA and EO muscle activation according to the hip flexion angles. This study suggests that we can selectively facilitate the muscle activity and exercise more effectively by considering the hip flexion angle when performing the quadruped position for enhancing the trunk stability.