Problems in defining and measuring friction on natural and artificial playing surfaces

Classical models of friction assume non-resilient surfaces, and are contact area independent. Pedestrian traction requirements remain controversial, as does the methodology of measuring coefficient of friction in situ. Athletic events, with severe maneuvers, can result in high traction requirements in order for the participants to successfully complete the activity. Typical outdoor athletic fields can be divided into natural and artificial surfaces, each with its own peculiar traction behavior when in contact with different athletic shoe outsoles. Friction testing devices, for use with athletic shoes and playing surfaces have been developed. However, traction requirements and appropriate test protocols have not been standardized.