Objective: The purpose of this study was to examine whether strap length influences the trunk motion and gait symmetry of the ground reaction forces while walking with a single-strap bag.
Methods: Seventeen Korean women participated in this study. The kinematics of trunk motion and ground-reaction forces was recorded while the participants walked at a self-paced speed under three conditions: no bag, a short-strap bag and a long-strap bag.
Results: The amplitude of trunk rotation on the ipsilateral side (the bag side) decreased while walking with a short-strap bag compared to walking with a long-strap bag or no bag (p< 0.05). The amplitude of trunk lateral bending toward the contralateral side and asymmetry in the mediolateral ground-reaction force significantly increased while walking with a long-strap bag compared to walking with a short-strap bag or no bag (p< 0.05).
Conclusions: These results demonstrate that carrying a long-strap bag during walking resulted in increased trunk lateral bending and asymmetry in the mediolateral ground-reaction forces. It is therefore important to select the correct strap length when carrying a single-strap bag to prevent musculoskeletal disorders.