Objective—To determine the association between
high-speed exercise and risk of injury while racing
among Thoroughbreds in Kentucky.
Design—Matched case-control study.
Animals—206 Thoroughbreds that sustained a musculoskeletal
injury while racing and 412
Thoroughbreds that were not injured during the same
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 during the 1- and 2-month periods
prior to the race in which injury occurred was significantly
less than that of control horses; for either
period, a difference of 10 furlongs was associated
with approximately 2-fold greater risk of injury.
Beyer's numbers were significantly higher for injured
horses than 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 significantly less cumulative highspeed
exercise than did control horses during the 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 United States. (J Am Vet Med Assoc 2000;