The physiological demands of a military dismounted assault task

Aim

Characterise the physiological demands of a military dismounted assault task (DAT) simulation. Method: Fourteen men (mean ± SD: age 29 ± 9 years; body mass 79.9 ± 9.2 kg; $\dot{V}$O_2peak 51.9 ± 4.4 ml·kg⁻¹·min⁻¹; upright pull strength 177 ± 20 kg) performed a DAT (external load 24.3 kg) of 16 × 6 m bounds in 20 s cycles (5 s work, 15 s rest) followed by an 18 m leopard crawl. Performance and physiological demands (heart rate and indirect calorimetry via the Douglas bag technique) during the first and last 48 m of bounds and the leopard crawl were compared using a one-way repeated measures ANOVA. Performance was maintained across the first and last 48 m (bound speed 5.7 ± 0.9 and 5.8 ± 0.8 km·h⁻¹) despite substantial increases in oxygen consumption (first 48 m 25.4 ± 3.3 ml·kg⁻¹·min⁻¹; last 48 m 31.7 ± 3.5 ml·kg⁻¹·min⁻¹; leopard crawl 40.4 ± 6.4 ml·kg⁻¹·min⁻¹, p < 0.001, Ѡ2 = 0.64). Mean leopard crawl time was 26.1 ± 8.1 s at a speed of 2.7 ± 0.8 km·h⁻¹ and post-exercise blood lactate was 3.8 ± 1.4 mmol·L⁻¹. Increasing oxygen consumption with modest blood lactate responses suggests the demands of the DAT simulation are similar to intermittent high-intensity exercise and that aerobic fitness is an important determinant of performance.