Metabolic energy expenditure and terrain coefficients for walking on snow.

Abstract Ten male subjects each walked at two speeds, 0·67 and 1·12 m s−1 (1·5 and 2·5 mph) on a level treadmill, and on a variety of snow depths. Energy expenditure increased linearly with increasing depth of footprint depression and was expressed, considering clothed weight, by the regression equation: energy expenditure (W kg−1 hor km−1 h−1) = 1·18 + 0·089 depression (cm). At 45 cm footprint depression as compared to a 0 cm depression, energy expenditure increased by a ratio of approximately 5 : 1. Although subjects were considered above average in terms of fitness [average [Vdot]O2max =51·4 ml kg−1 min−1 (n = 6)], all terminated walking due to exhaustion at an average footprint depth of 35·0 cm at a walking speed of 1·12m s−1. Practical limits for prolonged snow walking not exceeding approximately 50% [Vdot]O2max were developed with 20 cm being the maximal depth at 0·67 m s−1, and 10 cm at 1·12 m s−1 without snow shoes. At increased footprint depths, limiting factors for snow walking were the increasi...