The Effects of Soldiers’ Loads on Postural Sway

The purpose of the study was to investigate the effects of load weight and load configurations upon postural sway of Soldiers. Measuring postural sway may complement analyses of walking with loads, allowing for quick and efficient determination of how load carriage gear will impact the Soldier. Fourteen Army enlisted men participated in the study. Postural sway was measured while participants stood on a force platform. Soldiers were tested under four load weight configurations comprised of Army clothing and equipment: unloaded (6 kg), fighting load (16 kg), and march load (40 kg) with rucksack weight located close to the body and high in the pack, and a second march load (40 kg) with rucksack weight located far from the body and low in the pack. With an increase in weight, center of pressure excursions increased and Soldiers had to exert more control of the load to maintain balance. As the pack load weight position moved from high and close to low and away from the body, center of pressure excursions continued to increase and the rucksack became quite difficult for a load carrier to control precisely. This study demonstrated that an increase in load weight and a change in rucksack weight position changes both the individual’s postural sway and the structure of the sway.