Physiological, Biomechanical, and Maximal Performance Evaluation of Medium Rucksack Prototypes

Abstract : This report documents an evaluation of two prototypes of a medium-size rucksack. One prototype had a padded hip belt and a bag mounted on a frame. The other had an unpadded hip belt and a frameless bag. Eight Army enlisted men participated in the assessment of the relative effects of the prototype rucksacks on physiological, biomechanical, and maximal performance measures. The men also completed opinion surveys regarding the prototypes. The men were tested in a 17-kg fighting load alone and with the addition of each prototype. Both prototypes were loaded to a mass of 23 kg. Times to complete 30-m rushes and an obstacle course run did not differ between the prototypes, but were significantly slower than without a rucksack. Rate of oxygen uptake was recorded during treadmill walking at 0% and 9% grades and scaled to body mass. These data yielded higher energy consumption with than without a rucksack, but there was no difference between the prototypes. Spatio-temporal gait variables and ground reaction force variables were computed from kinematic and kinetic data recorded during walking and running. These data revealed differences between the fighting load alone and with the addition of a rucksack, but there were few differences between the two prototypes. The men s opinions favored the prototype with the padded hip belt and frame; six of seven men selected this prototype as the item they would prefer to use as their Army rucksack.

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