The effects of military body armour on the lower back and knee mechanics during box drop and prone to standing tasks

Modern day body armour (BA) has been successful at increasing survivability from previously lethal explosives; however, it has been suggested to reduce warfighter’s performance and increase risk of injury. Joint biomechanics have a foremost impact on performance and risk of injury. The immediate and prolonged effects of wearing BA on biomechanics of the lower back and knee during box drop (BD) and prone to standing tasks were investigated. The immediate effects of BA on both tasks were an increase of ≥4% (p≤0.02) in temporal task durations and a decrease of ~1.66N/kg (p=0.03) in normalised peak ground reaction force for the BD test. The prolonged duration of walking with BA (i.e. 45min) was not found to cause more changes in our measures than walking without BA. Quantitative data related to the effects of BA are important for risk assessment and mission design such to reduce the risk of injury without compromising performance. Practitioner Summary: The effects of wearing military body armour (BA) on biomechanics of the lower back and knee were investigated. Though wearing BA was found to affect some biomechanical measures related to performance, the prolonged effects of exposure on our measures were the same whether or not the participants wore BA.