The Effects of (A)symmetric Hand-Held Loads on Gait Performance in Young Males and Females

Abstract

Hand-held loading is a common part of daily movement. However, its effects on gait control in young adults remain incompletely understood. Previous work suggests that arm swing, load placement, and sex may each influence gait performance, but how these factors interact during hand-held loading has not been systematically examined. Therefore, this study investigated how unilateral and bilateral hand-held loads affect spatiotemporal gait parameters, gait variability, and whole-body kinematics in healthy young adults, and whether males and females show different adjustment strategies under load. Thirty participants walked on a treadmill under three conditions: natural walking, unilateral loading at 10% body mass, and bilateral loading at 10% body mass. Whole-body 3D kinematic data were collected using a 10-camera Vicon motion-capture system, and spatiotemporal metrics and variability (CoV) were derived from heel-strike–based gait segmentation. Joint range of motion (ROM) and ROM variability were calculated for the shoulders, torso, and lower limbs.

Hand-held loading mainly influenced gait on the non-dominant side. Participants walked with shorter stride length, longer stride time, and slower stride speed when carrying a load. Shoulder swing amplitude and trunk rotation decreased across loading conditions. These changes suggest that participants relied on upper-body adjustments to maintain stability. Additionally, certain loading conditions increased gait variability, including larger left stride-time variability under bilateral loading and increased variability in shoulder and trunk rotation. Although males and females showed similar joint-angle adjustments under most conditions, some variability measures still showed sex-related differences.

Overall, this study demonstrates that hand-held loading modifies upper-body control strategies during walking and places additional demands on temporal and kinematic stability. These findings provide a foundation for future work examining how hand-held loading influences gait in older adults and clinical populations.