Changes in postural sway and gait characteristics as a consequence of anterior load carriage

Abstract

Background: Anterior load carriage represents a common daily and occupational activity. Carrying loads in front of the body could potentially increase instability during standing and walking. Research question: This study examined the effects of anterior load carriage on postural sway and gait parameters in healthy adults. Methods: Twenty-nine participants (19 males, 10 females, age = 33.8 ± 12.7 years, height = 1.73 ± 0.07 m, mass = 75.1 ± 13.7 kg) were assessed in four conditions; (1) carrying no load (CON), (2) carrying a load with no added weight (i.e. empty box), (3) carrying a load with 5% body mass, and (4) carrying a load with 10% body mass. Anteroposterior and mediolateral centre of pressure (COP) displacement (cm) and the mean COP velocity (cm s-1) were used to characterise postural sway. Coefficient of variation of the stride length, stride time and double support time were calculated from 1 min of treadmill walking at a preferred pace for gait assessment. Results: The addition of the 10% load elicited an increase in anteroposterior COP displacement when compared to CON (d = 1.59), 0% (d = 1.50), and 5% (d = 0.75) (P < 0.001). The addition of the 10% load increased stride time (d = 1.71) and stride length (d = 1.20) variability when compared to CON (P < 0.001). Significance: In summary, the increase in postural sway and gait variability with added weight is dependent on the magnitude of the load, where the greater the load, the greater the effect on static and dynamic stability. Anterior load carriage potentially increases the risk of fall-related injuries.