Relationship of Racetrack Surface to Lameness in the Thoroughbred Racehorse

SUMMARY The high rate of occurrence of lameness in Thoroughbred racehorses in California was cause to suspect that racetrack surfaces might be partially responsible. To test this conjecture, a simple impact-testing machine was developed, and the peak impact force (F) from a standardized impact, similar to that of a running horse, was compared with the rate of occurrence of lameness (reported by trainers) normalized to a 15-week season for 5 occasions. The correlation seems to be linear for data accumulated over the period 1968-1970. Results of laboratory testing indicated that moisture content, dry density, and depth of layers of track surfaces affected F and permitted evaluating the risk of lameness and optimally conditioning racetrack soils to minimize lameness from this cause.