Human – natural sports surface interaction

The playing surface has a great influence on the outcome of a sport. It has a significant effect on the ball behaviour and the technical performance of skills of the sports participants, but it also impacts on their safety. This research is focused on the interaction of humans with natural turf pitches (NTPs). The project research integrates human body, and soil, mechanics in a laboratory environment by means of new technology and methodology to provide new understanding of this interaction. In a biomechanical study carried out using a portable pitch system, stresses and movements for nine male players performing running and turning movements on sand-based and clay-based NTPs revealed significantly greater peak vertical rate-of-loadings (dFz max ) and peak pressure rate-of-loadings (dP max ) for the sand compared to the clay-based condition. A further soil mechanical study to determine how the dynamic inputs from players affected the behaviour of those surfaces concluded that soil mechanical parameters such as moisture content and dry bulk density have a significant effect on the dynamic stiffness of the surface and that sand-based pitches have a significantly greater intrinsic stiffness than clay-based pitches explaining the observed biomechanical loading rate results. The research provides a step forward in the attempt to understand how humans interact with sports surfaces and how the surfaces respond. It highlights the importance of the elastic-plastic stress-strain behaviour of soils (or the soil-turf matrix) in response to stresses applied by humans and the difference in mechanical behaviour between sand and clay-based pitches. The findings of this research will inform sports engineers about the advantages of integrating biomechanical and soil mechanical data and lead them to ensure that surfaces that are safe to play and do not hinder the quality of the game by providing reasonable wear resistance, stiffness and traction values.