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