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

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 (Cw: 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 Cw values were determined from the ratio of 2-min steady-state oxygen consumption (Vo2) above resting value (net Vo2) to the walking speed (v): Cw = net Vo2/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.