Purpose: To quantify the metabolic demand of critical physically demanding tasks within the Royal Australian Navy (RAN). The metabolic demands of these tasks were then compared to criterion tasks performed by other occupational groups including Australian Army soldiers, NSW firefighters, and Royal Australian Air Force security.
Methods: Sixteen RAN personnel (14 males, 28.3 ± 10.6 years, 1.76 ± 0.1 m, 88.6 ± 18.2 kg) performed four criterion task scenarios: (1) performing storing (pass 114 items of 10–15 kg each); (2) responding to a toxic hazard by (2a) casualty search and fire-hose lift, or (2b) dragging a casualty, assisting a fire-hose lift, and performing a casualty lift and carry; and (3) walk 45 m in protective equipment and perform a fire suppression simulation. As per RAN protocol when moving about vessels, personnel were limited to walking. The duration to complete each scenario was recorded and oxygen consumption was measured continuously using a portable analyser (Meta-max 3B).
Results: Scenario 2b (casualty rescue) had a higher (p < 0.05) oxygen consumption (1.8 ± 0.2 L min−1) than Scenario 1 (storing: 0.9 ± 0.1 L min−1), Scenario 3 (fire-fighting: 1.5 ± 0.1 L min−1) and Scenario 2a (toxic hazard: 1.7 ± 0.2 L min−1). However, although storing had the lowest metabolic demand, it required a significantly longer duration to complete (830 ± 106 s) than Scenario's 2a, 2b and 3 respectively (418 ± 137 s, 485 ± 150 s, 769 ± 51 s, p < 0.05). The criterion task mean oxygen consumption and duration for the other trades are: Army combat arms soldiers performing a 10 km loaded march (2.0 L min−1, 110 min); firefighters performing a bushfire suppression simulation (1.7 L min−1, 52.3 min); and Air Force security tracking with a working canine (1.8 L min−1, ∼522 s).
Conclusions: The most metabolically demanding criterion task performed by RAN personnel elicited a lower demand than the criterion task performed by Australian Army soldiers. However the criterion tasks completed by NSW firefighters and Air Force security have a similar metabolic demand. The static nature of two of the RAN scenarios (1 and 3), the short duration of tasks performed within scenario 2, and a maximum walking pace contributed to a relatively low metabolic demand for RAN criterion tasks. Furthermore, the RAN criterion tasks predominantly require muscular strength or endurance.