Effects of load carriage, load position, and walking speed on energy cost of walking

Abstract

Purpose: The purpose of this study was to examine the effects of load, load position, and walking speed on the energy cost of walking per unit distance ( C w: ml/kg/m). Methods: Eight young male subjects walked on a treadmill at various speeds with and without load in the hands, on the back, and on the legs. The C w values were determined from the ratio of 2-min steady-state oxygen consumption ( V O 2 ) above resting value ( net V O 2 ) to the walking speed ( v): C w = net V O 2 /v . Results: An energy-saving phenomenon was observed when the load was carried on the back at slower speeds. This phenomenon diminished at faster speeds, particularly when walking faster than 90 m/min. It was also observed when the load was carried in the hands at slower speeds. Conclusions: These findings partly supported our hypothesis that an energy-saving phenomenon would be observed due to an interaction between rotative torque around the center of body mass and excessive burden on the lower muscles as a function of speed.