The Linearity of the Release Behavior of Artificial Turf Surfaces

This study quantified the release traction behavior of four artificial turf surfaces and two American football cleat surrogates. Four different loading conditions representing various play-relevant maneuvers were applied with a 6 DOF robotic test system. In all test conditions, a strong linear relationship was found to exist between normal force applied to the surface and peak shear force or moment resisted by the surface before release across varying normal force inputs. This linear relationship represents a release traction relationship that is the upper limit of the ratio of shear force to normal force that a player can generate without slipping. Changes in turf surface design parameters were shown to change the slope of the release traction relationship. The release traction relationship was shown to be insensitive to changes in loading condition or loading rate. Evaluations of the release traction behavior of surfaces can greatly improve future surface designs for player injury and performance.