Metabolic responses of South African soldiers during simulated marching with 16 combinations of speed and backpack load.
OBJECTIVE
This study assessed the metabolic responses of South African soldiers marching at different speeds and carrying varying loads. The main objective was to establish the physiological cost of a range of speed/load combinations to identify the energy requirements to meet a diversity of march objectives.


METHODS
Thirty male soldiers marched on a treadmill for 6 minutes with varying combinations of speed and load, established through numerous pilot studies and in consultation with military personnel. The four speeds were 3.5, 4.5, 5.5, and 6.5 km x (-1), combined with the four loads of 20, 35, 50, and 65 kg, totaling 16 combinations. Each participant completed eight of the 16 conditions, during which the participants wore standardized military gear and were attached to a portable ergospirometer (the Metamax, Cortex, Leipzig, Germany) for the duration of the march.


RESULTS
Based on the responses, five discrete categories of speed/load combinations were identified. These combinations were categorized as nominal (< 40% of maximal oxygen consumption [VO(2max)]), moderate (40-50% of VO(2max)), heavy (50-65% of VO(2max)), very heavy (65-80% of VO(2max)), and excessive (> 80% of VO(2max)), with each categorization incorporating diverse combinations of speed and load.


CONCLUSIONS
The findings demonstrate that the interplay between marching speed and backpack load plays a crucial role in ensuring that similar metabolic demands are maintained at a bearable level to meet specific military circumstances, thus reducing the likelihood of injuries and the early onset of fatigue and ensuring that the soldiers are combat ready on arrival at their destination.
Christie
Candice J
CJ
Department of Human Kinetics and Ergonomics, Rhodes University, Grahamstown 6140, South Africa.
Scott
Patricia A
PA
D000328:Adult; D004734:Energy Metabolism / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D008887:Military Medicine; D008889:Military Personnel; D013019:South Africa; D013997:Time Factors; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*