title: Metabolic responses of South African soldiers during simulated marching with 16 combinations of speed and backpack load.
abstract: 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.
authors.affiliation: Department of Human Kinetics and Ergonomics, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Candice J
authors.initials: CJ
authors.lastname: Christie
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Scott
mesh_terms: 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*