The development and validation of a performance infill tracking system to investigate rotational traction mechanisms on artificial turf surfaces

The scientific principles governing the generation of rotational traction forces on artificial turf remain poorly understood; as such, a photogrammetry technique has been developed to understand the interactions occurring at the boot-surface interface. Videos were recorded through a transparent test foot during rotational traction testing on an artificial turf surface "seeded" with distinguishable performance infill particles. A novel particle tracking software then measured the movement of seeded particles. To determine the uncertainty in the methodology, a gold-standard measurement system determined the distances between 28 fiducial markers. The same marker-to-marker distances were measured using the particle tracking software. For ten static and ten rotating trials, the random bias in the particle tracking software distances was ± 0.89 mm to ± 1.07 mm, respectively. A pilot study on a third-generation artificial turf surface assessed the software's ability to track infill particles during rotational traction testing. Trials were conducted at two normal loads; particle positions and angular displacements were successfully measured over 40° of rotation and synchronised with torque, angle, and vertical displacement data. A greater number of infill particles were lost during tracking at lower normal loads. This novel methodology represents a useful development in understanding the generation of traction forces, helping to inform future generations of artificial turf and studded footwear.