Changes in stature and spine kinematics during a loaded walking task.

The aim of the present study was to quantify the kinematics of the spine and stature loss induced by the asymmetric load carriage. Six healthy males with no history of low-back disorders walked at their self-selected pace for 8,500 m with and without a standard Royal Mail bag (model MB36) containing 17.5% of the participant's body mass. The load was reduced gradually during the task. The loaded condition produced a stature loss double that observed in the unloaded condition. Increased forward leaning (up to 6 degrees ) and lateral bending of the spine (up to 12 degrees ) was observed with load. Thoracic adjustments occurred in the sagittal plane, changes in the lumbar area occurred in the frontal plane. The data provided evidence against mailbags designs in which the workers cannot alternate the side of the mailbag.