Validation of a Laboratory Method for Evaluating Dynamic Properties of Racetrack Surfaces

Dynamic impact properties of racetrack surfaces can be evaluated on a small scale in a controlled laboratory setting. Authors’ address: Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, CA 95616; e-mail: [email protected].

1. Introduction

Race surface is a risk factor for musculoskeletal injuries, because surface dynamic impact properties affect forces transmitted to the hooves and limbs. Measurements of surface properties at racetracks are confounded by environmental variation and limited to existing racetrack surfaces. Our objective was to validate a system for measurement of the dynamic impact properties of race surfaces on a small scale in a controlled laboratory environment.

2. Materials and Methods

Measurements were made during simulated hoof impacts at dirt and synthetic racetracks. Harvested surface materials were reconstructed over a synthetic racetrack surface base in a laboratory box. Laboratory measurements were compared with racetrack measurements and dirt surface properties were compared with synthetic surface properties using t tests (p ≤ 0.05).

3. Results

Laboratory dirt and synthetic surface measurements were within 10% of racetrack dirt and synthetic averages. Laboratory racetrack differences were small (<14%) relative to the differences between racetrack dirt and synthetic surfaces for impact variables relevant to injuries, including vertical peak force, average load rate, and average stiffness.

4. Discussion

Measurements of dynamic impact properties of dirt and synthetic race surfaces reconstructed in the laboratory were representative of actual racetrack surface behavior and useful for comparison of different racetrack surfaces. Racetrack surfaces and the effects of different factors on surface behavior can be evaluated on a small scale in a controlled environment.

Acknowledgment

Supported by a University of California, Davis Dissertation Year Fellowship and grants from the Grayson-Jockey Club Research Foundation, the Southern California Equine Foundation, and the Center for Equine Health with funds provided by the State of California pari-mutuel fund and contributions by private donors. The authors thank Golden Gate Fields and Pleasonton racetracks and their employees for their assistance.