Changes in trunk displacement and ground reaction force during right-left hand-behind-back movement

[Purpose] The purpose of this study was to compare the trunk displacement and ground reaction force during hand-behind-back (HBB) movements between the right and left hands. [Participants and Methods] Twenty healthy right-handed men participated in this study. The measurement task involved performing HBB movements while standing, using a three-dimensional motion capture system and two force plates. Changes in trunk displacement and ground reaction force were measured to evaluate differences between the right and left hands at the examined level. [Results] Anterior trunk displacement was observed when the thumb reached the pelvis. The ground reaction force on the side of the HBB movement increased during this phase and decreased as the thumb touched the eighth thoracic vertebra. No significant differences were observed between right and left hands. [Conclusion] Anterior trunk displacement and changes in ground reaction force occurred in both right and left hands during HBB movement, with no differences observed between the right and left sides. During physical therapy evaluation and treatment, focusing on changes in trunk displacement and loading on the lower extremity on the side of the HBB movement may be useful.