Influence of floor inclination and bracing surface availability on hand forces production capacity, ground reaction forces, and postural adjustments during one-handed pulling task

Floor inclination is a significant ergonomic challenge in sectors like aviation and naval operations, where operators generate substantial hand forces while adjusting body balance on non-horizontal surfaces. Previous studies showed standing on inclined floors reduces maximal hand forces, induced by the sharing of neuromusculoskeletal resources between balance control and force production. Providing a bracing surface could mitigate these force declines, but to an unknown extent. This study aimed to quantify the combined effects of sagittal-plane floor inclination (±30°) and left-hand bracing availability on maximal right-hand pulling force, ground-reaction forces, and whole-body posture. Participants performed maximal isometric pulling trials on force platforms, while a marker-less motion-capture system tracked key body positions. The main results revealed that without a bracing surface, forward inclinations markedly reduce maximum pulling force: −32% at 15° and −77% at 30° compared to 0°. A left-hand bracing surface largely mitigated these effects. Compared with the braced horizontal condition, forward inclinations produced smaller decreases of 15% at 15° and 23% at 30°. Bracing increased force by 40% at 0° and by approximately 75% and 370% at 15° and 30° forward inclinations, respectively. These findings confirm the crucial role of floor inclination in limiting force production and postural stability and highlight the importance of using bracing surfaces to mitigate performance decrease. The recommendations include integrating accessible handholds in inclined workstations to enhance safety and efficiency in tasks demanding substantial hand pulling forces.