Soldier-relevant body borne load impacts minimum foot clearance during obstacle negotiation

Soldiers often trip and fall on duty, resulting in injury. This study examined ten male soldiers' ability to negotiate an obstacle. Participants had lead and trail foot minimum foot clearance (MFC) parameters quantified while crossing a low (305 mm) and high (457 mm) obstacle with (19.4 kg) and without (6 kg) body borne load. To minimize tripping risk, participants increased lead foot MFC (p = 0.028) and reduced lead (p = 0.044) and trail (p = 0.035) foot variability when negotiating an obstacle with body borne load. While obstacle height had no effect on MFC (p = 0.273 and p = 0.126), placing the trail foot closer to the high obstacle when crossing with body borne load, resulted in greater lead (R = 0.640, b = 0.241, p = 0.046) and trail (R = 0.636, b = 0.287, p = 0.048) MFC. Soldiers, when carrying typical military loads, may be able to minimize their risk of tripping over an obstacle by creating a safety margin via greater foot clearance with reduced variability.