Physiological and Perceptual Responses to Prolonged Treadmill Load Carriage

The objectives of this study were to determine the physiological and perceptual responses to prolonged, level treadmill walking at speeds of 3.96, 4. 86, and 5.76 kilometers per hour, unloaded and with external loads load carriage equipment backpack of 31.5 and 49.4 kilograms determine the ability of subjects to perform high intensity, anaerobic exercise Wingate test immediately after load carriage and compare the energy cost and perceptual responses of carrying the standard external frame pack to that of the new internal frame system. Fifteen male subjects performed nine load carriage trials with an external frame pack All-Purpose Lightweight Individual Carrying Equipment ALICE and two trials with an internal frame pack Integrated Individual Fighting System IIFS in random order over a 7 week period. At the end of each trial blood samples were taken for the measurement of lactate and subjects performed either an upper or lower body anaerobic power test. Oxygen Uptake VO2, Minute Ventilation VE, heart rate, and differentiated ratings of perceived exertion Ratings of Perceived Exertion RPE were determined at the end of the first 10 min and every 20 min thereafter for the duration of the trial. A 10 min rest period was allowed each hour. No changes occurred in VO2 over time in the unloaded condition at any speed. jg