The effects of military body armour on the lower back and knee mechanics during toe-touch and two-legged squat tasks

Abstract

While effective in the prevention of otherwise lethal injuries, military body armour (BA) has been suggested to reduce warfighter's performance and increase injury-related musculoskeletal conditions. Providing the significant role of joint biomechanics in both performance and risk of injury, the immediate and prolonged effects of wearing BA on biomechanics of the lower back and knee during toe-touch (TT) and two-legged squat (TLS) tasks were investigated. The immediate effects of BA were an increase of >40 ms (p ≤ 0.02) in flexion duration of the dominant joint and an ∼1 s (p ≤ 0.02) increase in overall task duration as well as an ∼18% (p = 0.03) decrease in the lumbopelvic rhythm ratio near the mid-range of trunk flexion. In general the prolonged duration of wearing BA (i.e. 45 min of walking) was not found to cause more changes in our measures than walking without BA.

Abstract

Practitioner Summary: The effects of wearing military BA on biomechanics of the lower back and knee during TT and TLS tasks were investigated. The immediate effects of BA were increased flexion duration, increased overall trial duration and decreased lumbopelvic rhythm near the mid-range of trunk flexion.

Keywords::

• military body armour
• prolonged walking
• performance
• risk of injury
• military ergonomics

Notes

^1. Email: [email protected]

^2. Email: [email protected]

^3. Biodex Medical Systems, I. BIODEX System 3 Advantage Software Operations Manual: 11–15.

Additional information

Funding

M.P. acknowledges support from VA Chapter 33. Statistical assistance was provided by University of Kentucky's CCTS [grant number UL1RR033173]; [grant number UL1TR000117].