carry-over effects of backpack carriage on trunk posture and repositioning ability

immediate effects of backpack carriage on spinal curvature and motor control in adults have been reported. however, there is a scarcity of evidence whether the effects would persist or not after the carrying load is removed. this study aimed to investigate the carry-over effects of backpack carriage on trunk posture and repositioning ability. thirteen healthy adults were recruited and instructed to walk on a treadmill for 30 min with backpack (10% body weight) followed by 30-min unloaded walking. participant’s trunk posture and repositioning ability were measured at different time points. during backpack carriage, reduction in lumbar lordosis and posterior pelvic tilt with significant increased cervical lordosis, thoracic kyphosis and trunk forward lean were observed. there was also a significant increase in repositioning errors in all spinal curvatures and trunk forward lean. after removal of the carrying load, there was a tendency for restoration of trunk posture and repositioning ability. however, the cervical lordosis and the repositioning error of all spinal curvatures could not be fully returned to the levels of the preload condition (all p < 0.05). the persistent changes in both spinal curvature and repositioning ability revealed an increased risk of spinal injury even after the backpack was removed, and the effects on the neck and back pain warrant future study. relevance to industry the effects of backpack carriage (10% body weight for 30 min) on the spine could not be fully restored after 30-min unloaded walking. the persistent changes in both spinal curvature and repositioning ability revealed an increased risk of spinal injury even after the backpack was removed. proper postural reminder might be given to backpack users to alleviate the adverse effects induced after prolonged backpack carriage.