Association of high-speed exercise with racing injury in Thoroughbreds

Objective--To determine the association between high-speed exercise and ris k of injury while racing among Thoroughbreds in Kentucky. Design--Matched case-control study. Animals--206 Thoroughbreds that sustained a musculoskeletal injury while ra cing and 412 Thoroughbreds that were not injured during the same races. Procedure--Data regarding official timed workouts and,races and the Beyer's numbers for the 3 races before the race during which injury occurred were extracted from past performance charts and compared between injured horses and control horses. Results--For injured horses, cumulative distance of high-speed exercise dur ing the 1- and 2-month periods prior to the race in which injury occurred w as significantly less than that of control horses; for either period, a dif ference of 10 furlongs was associated with approximately 2-fold greater ris k of injury. Beyer's numbers were significantly higher for injured horses t han for control horses. These effects remained significant after adjusting for age and results of prerace physical inspection. Conclusions and Clinical Relevance--In Kentucky, injured horses had signifi cantly less cumulative high-speed exercise than did control horses during t he 1-and 2-month periods prior to the race in which injury occurred. These results differ from those observed in California. The association of injury with cumulative high-speed exercise appears to vary among regions in the U nited States.