Assessing the performance of winter footwear using a new maximum achievable incline method

• We assess footwear slip resistance on ice by the maximum slope angles subjects could stand and walk.
• The maximum slope angles were objective and ecologically valid measures of slip resistance.
• We tested footwear performance while standing and walking uphill, downhill, and on cross-slopes.
• This human-centred measure of slip resistance did not require controlling of individuals' gait characteristics.
• One outsole design significantly outperformed the others on the smooth, wet ice.

More informative tests of winter footwear performance are required in order to identify footwear that will prevent injurious slips and falls on icy conditions. In this study, eight participants tested four styles of winter boots on smooth wet ice. The surface was progressively tilted to create increasing longitudinal and cross-slopes until participants could no longer continue standing or walking. Maximum achievable incline angles provided consistent measures of footwear slip resistance and demonstrated better resolution than mechanical tests. One footwear outsole material and tread combination outperformed the others on wet ice allowing participants to successfully walk on steep longitudinal slopes of 17.5° ± 1.9° (mean ± SD). By further exploiting the methodology to include additional surfaces and contaminants, such tests could be used to optimize tread designs and materials that are ideal for reducing the risk of slips and falls.