Effect of Equipment Weight on Energy Cost and Efficiency during Simulated Uphill Ski Touring

Purpose The purpose of this study was to quantify changes in energy cost (EC) associated with increased ski touring equipment weight during simulated uphill ski touring at a constant speed and grade and to identify potential factors affecting energy cost other than equipment weight. Methods 8 subjects skinned on a treadmill at a constant speed and grade using three different ski touring setups (6.1, 7.9 and 10.4kg in total mass) in a randomized order. Heart rate, respiratory exchange ratio, blood lactate concentration and energy expenditure were measured while subjects maintained a steady state workload. Results A statistically significant positive correlation was found between total weight (setup mass + participant mass) and energy cost (r = 0.501, n = 24, p < 0.05). Non-linear increases were found in EC (13.8, 14.7, 16.3 J kg-1m-1), heart rate (164, 167, 177 bpm) and oxygen consumption (41.8, 44.3, 49.1 mL kg-1min-1) with 6.1, 7.9 and 10.4kg setups respectively. Conclusions A significant relationship exists between equipment weight and measured energy cost of uphill skinning, but a greater increase in workload was observed between the 7.9kg and 10.4kg setups compared to the changes found between the 6.1kg and 7.9kg setups. This may be due to the binding design on the heaviest setup, which was different from the bindings on the two lighter setups. When choosing an equipment setup, recreational ski mountaineers should consider the type of binding used and its potentially greater effect on energy cost compared to equipment weight alone.