An Initial Investigation of Human-Natural Turf Interaction in the Laboratory

Abstract

It is essential to provide high quality, safe and affordable sports surfaces in order to attain the health and social benefits from sports participation. Investment, construction and research into artificial sports surfaces have increased to meet this provision (Kolitzus, 1984; Nigg & Yeadon, 1987). Full provision cannot be met without natural turf surfaces, which also have an important role as greenspaces in the built environment. For improved access to sports facilities, there needs to be a significant improvement in the durability of natural turf surfaces and thus greater understanding of the human-natural sports surface interaction. Research into human interaction with natural surfaces is complicated by integrating natural soil media and sustaining turf growth in the laboratory environment. This study describes and provides data on methodology incorporating the biomechanical assessment of natural turf in the laboratory. Practicalities of using natural turf in the laboratory were overcome by using 10 portable plastic trays (0.57 m×0.38 m×0.08 m), turfed with ryegrass in a sand rootzone. Trays were positioned lengthways in the laboratory on non-slip matting (6 mm thick) to form a continuous runway and cover the force plate (AMTI, 960Hz). Ground reaction force (GRF) data were collected from two subjects wearing football boots (artificial turf/hard pitch design) for running, turning, and acceleration from rest. Mean GRF values compared well with the range of magnitudes presented in the literature for similar movements (Stucke, Baudzus & Baumann, 1984; Munro, Miller and Fuglevand, 1987; Miller, 1990) demonstrating Baumann, 1984; Munro, Miller and Fuglevand, 1987; Miller, 1990) demonstrating that the incorporation of natural turf in the laboratory environment has been achieved successfully. Compared to running (subject 1, −0.41±0.06 BW; subject 2, −0.34-±0.04 BW), peak horizontal force increased for turning (subject 1, −0.50±0.06 BW; subject 2, −0.90±0.01 BW) and accelerating from rest (subject 1, −0.52±0.05 BW; subject 2, −0.44±0.09 BW), reflecting greater braking and propulsive requirements for the respective movements for both subjects. Peak vertical impact forces were 1.89 BW (±0.24) and 2.01 BW (±0.26) for subjects 1 and 2 respectively during running and 1.40 BW (±0.02) and 2.57 BW (±0.37) respectively during turning. To improve human-natural turf interaction, future studies will assess multiple subjects, movements, footwear and a range of natural turf condition using the methodology developed here.