Training practices, speed and distances undertaken by Thoroughbred racehorses in Victoria, Australia

Abstract

Background: Musculoskeletal injuries (MSI) in racehorses are commonly due to bone fatigue, a function of the number of cycles (strides) and the magnitude of load applied to the limb. These parameters can be estimated using speed and distance, with greater than 6000 m/month at a gallop (>14 m/s), in combination with canter distances greater than 44,000 m/month, reported to increase fracture risk. Despite their importance, there are limited data on the distances and speeds horses are exposed to during training.

Objectives: Estimate training volume at different speeds undertaken by Australian Thoroughbred racehorses.

Study design: Cross-sectional study.

Methods: Registered trainers (n = 66) in Victoria, Australia were surveyed. Questions were designed to assess the full training workload from initial pre-training to training performed to achieve and maintain race fitness, as well as information on rest periods. Descriptive analyses were stratified by trainer- and horse-level factors, with assessment of variance within and between groups. Cluster analyses were used to identify similar workload intensity groups.

Results: Horse-level factors (age, targeted race distance) were associated with workload (younger<older, sprinters<stayers). Trainer categorisation did not influence workload, but there was significant variation in volume of total gallop exercise between trainers (median gallop distance 8000 m/month [IQR 6400-12,000]). Cluster analyses identified four workload programmes (medians): low-intensity (4800 m/month), medium-volume (8000 m/month), medium-volume with a higher proportion of high-speed workouts (12,800 m/month) and high-volume programmes (19,200 m/month), with 23, 50, 17 and 9% of trainers predominately training racehorses under each of the respective programmes. Horses 3-years and older were rested twice yearly for 6.3 (95% CI 5.7, 6.8) weeks, with more experienced trainers resting horses for shorter periods (P = 0.03).

Main limitations: Possible selection bias, subjective reporting of workloads by trainers.

Conclusions: Australian Thoroughbred training programmes include high volumes of galloping with more than half exceeding previously reported risk levels for MSI.

Keywords: exercise; gallop; horse; rest period; workout.