Footwear has a modifying effect on tibial loading during military weight carriage

Abstract

This study investigated how different footwear conditions influence tibial loading across incremental load carriage during walking. Ten military-trained male participants completed walking trials under three weight conditions (0, 15, and 30 kg) and three footwear conditions (barefoot, trainers, and military boots) at 1.67 m/s. Kinematic (120 Hz) and kinetic (1200 Hz) data were collected using motion capture and force plates. Tibial loading was estimated via musculoskeletal modeling and beam theory, focusing on peak tibial bending moments and cumulative-weighted tibial impulse. A two-way repeated measures ANOVA ([Formula: see text]) examined main effects and interactions of load and footwear. Post hoc pairwise comparisons with Bonferroni corrections ([Formula: see text]) identified significant differences. A significant interaction effect was observed for peak tibial bending moments and cumulative-weighted tibial impulse per kilometer ([Formula: see text]). In trainers, tibial loading increased progressively across all loads (0 kg < 15 kg < 30 kg, all [Formula: see text]). In military boots, loading increased from 0 to 15 kg ([Formula: see text]) but not between 15 and 30 kg. Weight carriage increased tibial loading, but footwear modified this relationship. Military boots showed no significant change between 15 and 30 kg. These findings suggest implications for tibial stress injury, though further research is needed.

Keywords: Bending moment; Cumulative loading; Load carriage; Military boots; Tibial stress injury; Walking.

Fig. 1

Mean time-series data of resultant bending moment (A), JRF component of bending moment (B), and muscular force component of bending moment (C) during the stance phase of walking under different weight conditions (0 kg, 15 kg, and 30 kg) and footwear conditions (barefoot, trainers, and military boots).

Fig. 2

Mean peak tibial bending moment (A) and cumulative-weighted tibial impulse per kilometer (B) at the distal third of the tibia during the stance phase of walking under three weight conditions (0 kg, 15 kg, and 30 kg) and three footwear conditions (barefoot, trainers, and military boots). Error bars represent the standard deviation.

Fig. 3

Ankle joint peak negative power (A), peak positive power (B), total negative work (C), and total positive work (D) across three weight conditions (0 kg, 15 kg, and 30 kg) and three footwear conditions (barefoot, trainers, and military boots). Error bars represent standard deviation. * indicates significant differences identified through post-hoc pairwise comparisons following a significant interaction effect, and ** indicates significant differences identified through post-hoc pairwise comparisons following a significant main effect, both at .

Fig. 4

Examples of unloaded (0 kg) and loaded (15 and 30 kg) conditions during walking. (A) barefoot-unloaded; (B) trainers-unloaded; (C) military boots-unloaded; (D) barefoot-loaded; (E) trainers-loaded; (F) military boots-loaded.