Tensile Force Transmission from the Upper Trunk to the Contralateral Lower Leg throughout the Posterior Oblique Sling System

Abstract

Although recent studies have confirmed that muscles of the upper body are obliquely linked with the muscles of the contralateral lower extremity through posterior oblique sling (POS) system, the upper portion of the POS connected to the lower leg below the hamstring is yet to be determined. In the supine position, the active maximum dorsiflexion (DF) angles of the right and left legs were randomly measured. During passive trunk rotation performed by the therapist, the active maximum DF angles of the right leg (contralateral side) and left leg (ipsilateral side) were measured. In a long sitting position with and without trunk rotation, the active maximum DF angles in both legs were measured. The left upper body was made to rotate rightward in trunk rotation. In the contralateral lower extremity, the DF ROM in the sitting position with trunk rotation was significantly different compared with those in the sitting position without trunk rotation, and in the supine position with trunk rotation. In the comparison between the ipsilateral and contralateral lower extremity, significant differences were found in the DF ROM in the sitting position with trunk rotation. This study indicates that the tensile force generated by trunk rotation is transmitted to the contralateral terminal end by examining changes in DF ROM. Since the upper portion of the POS is connected all the way down to the contralateral calf, the POS must be considered during the clinical treatment of patients with restricted DF mobility.