The effect of footwear outsole material on slip resistance on dry and contaminated surfaces with geometrically controlled outsoles

Abstract

Previous studies have compared slip resistance of commercially available footwear, however, often lacking the ability to isolate factors such as material and surface properties, or/and geometry. The aim of this study was to compare slip resistance of geometrically identical shoes with varying outsole materials. Three left Ecco Xpedition III shoes were constructed out of three different outsole materials: polyurethane (PU), thermoplastic polyurethane (TPU) and vulcanised rubber (RU). The shoes were tested for dynamic coefficient of friction (DCOF) on a steel and a tile surface, without contamination and with glycerine and canola oil as contaminants. The shoes were significantly (p < 0.001) different from each other across all surface/contaminant conditions/combinations, with the PU having a significantly 61–125% (p < 0.001) higher DCOF on contaminated surfaces compared to the RU outsole.

Practitioner summary: Previous research has suggested the importance of studying individual parameters separately of footwear in relation to slip resistance. In this study, we managed to construct geometrically identical shoes and compare the slip resistance between three different outsole materials. We found that the polyurethane outsole was the least slippery choice of material for this specific footwear model on contaminated surfaces.

Keywords:

• Friction
• footwear
• traction
• slips trips and falls

Acknowledgments

ECCO Shoes A/S manufactured the shoes used in this study but had no role in the interpretation and presentation of the results. The authors want to thank Sophia Sachse from ECCO A/S for her extensive help and very fast execution.

Disclosure statement

The authors have no conflict of interest to declare.

Additional information

Funding

This study was funded by the Danish Working Environment Research Fund [grant number: 20195100816].