RESUMEN
PURPOSE: This study was conducted to investigate the effects of variations in arm swing during gait on movement of the trunk and pelvis. During the gait task, the angle of the trunk and pelvic rotation were analyzed according to arm swing conditions. METHODS: Seventeen healthy males participated in this study. All subjects were analyzed for gait on a treadmill three times each under three different types of arm swing conditions – natural arm swing, restricted arm swing using a phone, restricted swing in both arms. 3-D motion analysis systems were used to collect and analyze the kinematic data of trunk and pelvic movements, and repeated one-way ANOVA was used to compare the trunk and pelvic kinematic data and symmetry index. The level of significance was α=0.05. RESULTS: The results showed kinematic differences in trunk and pelvic during gait based on the arm swing conditions. Specifically, there were significant differences in trunk rotation, left and right trunk rotation and symmetry index of trunk rotation during gait among the three arm swing conditions. ROM was used to calculate a symmetry index (SI) based on the average left and right trunk rotation in which a value closer to zero indicated better balance. The SI obtained for arm swing restricted with the phone was closer to –1 than the other conditions. CONCLUSION: Restricted arm swing due to use of a phone had the possibility to induce instability of postural control while walking, which could be seen to suggest a risk of falling during gait.