Examination of Movements Related to the Trunk and Pelvis during the Buttocks Release Phase of Standing Up Movement

Abstract

[Purpose] The purpose of this study was to clarify the motions related to the trunk and pelvis during the buttocks release phase of the standing up motion. [Participants and Methods] Fifteen healthy male subjects were asked to stand up and the changes in joint angles were measured using image analysis software. [Results] Anterior pelvic tilt, knee joint extension, and anterior tilt of the lower leg increased in the early and late phases of buttocks release. In addition, anterior trunk tilt and thoracolumbar transitional flexion increased in the early phase, and posterior trunk tilt and hip extension increased in the late phase. The movement patterns were divided into 16 patterns. [Conclusion] The results suggest that thoracolumbar transitional flexion plays a significant role in anterior trunk tilt during the early phase of buttocks release, and hip extension plays a significant role in posterior trunk tilt during the late phase. Furthermore, the results also suggest that knee joint extension with ankle dorsiflexion is largely responsible for anterior pelvic tilt.