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Energy cost during locomotion across snow: a comparison of four types of snowshoes with snowshoe design considerations.

Snowshoes are a common method of locomotion across snow but no investigations has previously examined the energy cost of different snowshoe models or looked for desirable snowshoe design characteristics. To this end, four Marines were studied while walking at 4 km/h in four different types of snowshoes. They traversed a field with an average grade of 2.4%, walking once downhill and once uphill with each snowshoe. Expired respiratory gases (for energy cost measures) and heart rates were collected continuously during the walk. The Pride Assault and US Army Standard models had a lower energy cost than the Montana Light model and tended to have a lower cost than the British Assault model. Correlations between snowshoe mass/surface area ratios and energy cost were 0.81 and 0.72 on the uphill and downhill portions of the course, respectively. Examination of the physical attributes of the snowshoes suggested several design characteristics may be favorable from an energy cost perspective: 1) a hinge-and-binding system that allows the snowshoe to be dragged across the snow, 2) an upturned front that pushes snow away and allows a more horizontal (less vertical) displacement of the snowshoe during locomotion, 3) a narrow profile that avoids leg abduction, and 4) a lower mass to surface area ratio. Further research will be necessary to determine the importance of these factors because of the limited number of subjects and the single snow condition examined here.