title: Effects of heavy load carriage during constant-speed, simulated, road marching.
abstract: Load carriage is a key element in dismounted military operations. Load carriage requirements in the field regularly exceed 50% of lean body mass (LBM) and have only rarely been studied. Therefore, our purpose was to determine the metabolic and motivational effects of heavy loads (30-70% LBM) during constant-rate "road" marching on a treadmill. Ten healthy male Army officers carried loads of 30%, 50%, and 70% LBM in an all-purpose, lightweight, individual, carrying equipment pack for 30 minutes, at a speed of 6 km/h. Oxygen consumption (VO2), ventilation, heart rate (HR), respiratory exchange ratio, rating of perceived exertion (RPE), and Self-Motivation Inventory scores were recorded at each trial. Significant increases were observed for VO2, ventilation, and HR between the trials. RPE significantly increased for the 70% LBM trial, compared with the 30% and 50% trials. No significant differences were seen in respiratory exchange ratio or Self-Motivation Inventory scores. Increasingly heavy loads carried in a rucksack resulted in increased VO2, RPE, and HR; therefore, increasing the load that a soldier is required to carry may negatively affect road march performance.
authors.affiliation: Department of Physical Education, U.S. Military Academy, West Point, NY 10996, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Beekley
authors.forename: Jonathan
authors.initials: J
authors.lastname: Alt
authors.forename: Clyde M
authors.initials: CM
authors.lastname: Buckley
authors.forename: Michael
authors.initials: M
authors.lastname: Duffey
authors.forename: Todd A
authors.initials: TA
authors.lastname: Crowder
mesh_terms: D000328:Adult; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008887:Military Medicine; D008889:Military Personnel; D009042:Motivation; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D010865:Pilot Projects; D012420:Running / Q000502:physiology; D014481:United States; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*