Abstract
Purpose: This study investigated the influence of pelvic alignment in the sagittal plane on the range of rotation of the thorax, pelvis, and spine, and the movement of the center of mass during active rotation in standing.
Methods: This study examined 17 males with no musculoskeletal disorders. Using a three-dimensional motion analysis system, we measured the range of rotation of their thorax, pelvis, and spine, and the posterior and lateral movement of the center of mass during active rotation in standing. The anterior pelvic tilt in the starting position included three conditions: normal standing (neutral), 5 degrees anterior of neutral (anterior position), and 5 degrees posterior of neutral (posterior position). We compared the range of rotation and the movement of the center of mass in the three conditions.
Results: Regarding rotation, in the anterior and posterior positions, the range of thoracic, pelvic, and spinal rotation was significantly smaller than in the neutral position. In the posterior position, the range of spine rotation was significantly smaller than in the anterior position. Regarding the movement of the center of mass, in the anterior position, posterior movement was significantly smaller than in the neutral position and lateral movement was significantly larger than in the neutral position. In the posterior position, the posterior and lateral movements were significantly larger than in the neutral position.
Conclusions: These data suggest that pelvic alignment in the sagittal plane influences the range of rotation of the thorax, pelvis, and spine and the movement of the center of mass during active rotation in standing.
