Relationship between iliopsoas muscle thickness and hip angle during squats in different pelvic positions

Abstract

This study aimed to investigate the relationships among the changes in iliopsoas muscle thickness, hip angle, and lower limb joint moment during squatting in different pelvic positions to help in performing hip-dominant squatting exercises. [Participants and Methods] The participants were seven healthy adult males. The measurement task consisted of squatting with 60 degrees of knee flexion in three positions: the anterior, neutral, and posterior pelvic tilt positions. The iliopsoas muscle thickness was measured in the center of the inguinal region using ultrasonography. A three-dimensional motion analysis system was used to measure the joint angles and joint moments. [Results] There were no significant differences in pelvic angles between the pelvic positions. The hip angle differences were significantly higher in the anterior and neutral pelvic tilt positions compared to those in the posterior tilt position. Only the anterior pelvic tilt position had a significantly positive correlation with iliopsoas muscle thickness and hip angle differences. [Conclusion] Squatting in the neutral or posterior pelvic tilt position was not associated with hip angle and iliopsoas muscle thickness changes, whereas squatting in an anterior pelvic tilt position was associated with changes in the iliopsoas muscle thickness and hip flexion angle. Our findings suggest that activation of the iliopsoas muscle might be necessary to promote hip-dominant squatting.

Effects of Pelvic-Tilt Imbalance on Disability, Muscle Performance, and Range of Motion in Office Workers with Non-Specific Low-Back Pain

“…Kisuke et al [ 39 ] reported that when the anterior-pelvic-tilt angle increased by 1 degree, the anterior coverage of the femoral head increased by 0.5%, and the posterior coverage decreased by 0.3%. In addition, when the anterior pelvis tilts, the iliopsoas-muscle tone increases, and when the posterior pelvis tilts, the hamstring shortens and its muscle tone increases [ 40 , 41 ]. The reason why the difference in left and right pelvic tilt in this study changed the hip-joint-rotation ratio is thought to be because the difference in the tilt of the left and right pelvis changed the femoral head coverage and also changed the length and tone of the muscles around the hip joint.…”