Does Training Defined By Speed Zones Accurately Reflect Racehorse Workload?

Despite recent advances in the technology available for use across equestrian disciplines, racehorse training remains largely based on anecdotal and traditional practices. A key premise of racehorse training is to produce horses which are fit and can perform to their best in competition (at the races). Training practices vary between yards but internal training is commonly used, with racehorse workload defined by the speed the horses are exercised at; for example: quarter speed (QS), half speed (HS), three quarter speed (TQS) and full speed (FS). Whether this approach is successful tends to be judged via observational assessment of workload by the trainer and the work rider. This approach could potentially risk overtraining and injuring the horses involved if the speed or workload of the horses differ to that which is perceived to be undertaken. This study evaluated if speed zones (SZ) and estimated workload varied across a 6 week period in the middle of the British National Hunt season, 2017/18. Nine ‘race-fit’ thoroughbred racehorses (age: 8.0±2.3 years) of variable experience (races: 14±11) and ability (official rating: 103±14) were recruited for the study. Fine Equinity™ heart rate (HR) monitoring systems collected HR and speed data for each horse during all interval training sessions during the study period. Gallop exercise sessions took place on a 4 furlong (805m) all-weather gallop (sand and carpet fibre mixture; 8cm depth). Workload levels were determined by the same experienced National Hunt trainer; a typical week’s training consisted of day 1: 2xQS gallops, day 2: 2xQS & 1xFS gallops, day 3: road-work, day 4: 3xQS gallops, day 5: road-work or 2xHS gallops, day 6: 2xTQS & 1 FS gallop, day 7: horse walker (30minutes). Horses were warmed up prior to gallop sessions (400m) and trotted halfway down the gallops (350m) and then walked to the end (350m), at the end of gallop exercise horses were walked (500m) to cool down. Workload (defined as age-adjusted mean percentage of HR maximum) and speed for each gallop run were recorded and SZ were noted from the trainer. Speed increased incrementally as the SZ progressed: QS:31.17km/h, HS:33.09km/h, TQS:36.55km/h, FS:41.59km/h. Racehorses’ actual speed varied as expected between furlongs within SZ (Kruskal Wallis(KW): P = 0.0001) with significant increases recorded between all SZ for F1, 2, 3 and 4(Mann Whitney U(MWU): P<0.01), except between QS-HS for all furlongs (P>0.05) and TQS-FS for F4 (P>0.05). Interestingly, racehorse workload only varied with SZ for F1 (KW: P=0.003) with increased workload found between HS-FS, TQS-FS AND QS-FS (MWU: P<0.02) but not for QS-HS, QS-TQS and HS-TQS (P>0.05). These results suggest workload was not consistent across SZs for F2-4 (P>0.05) and horses were therefore not working as the trainer intended. Accurately monitoring speed and workload during galloping could provide trainers with a more accurate approach to training than using allocated speed zones and judging performance through observation. Lay person message: Monitoring racehorses’ speed and heart rates during training can provide their trainers with an indication of how training is progressing. Racehorses’ average workload and speed was recorded and analysed against trainer allocated speed zones (SZ) to see if differences existed. Speed did increase between the speed zones but no difference was found between quarter and half speed work. Similarly, racehorse workload only varied during the first furlong of work, regardless of the SZ they were working at. Monitoring speed and workload could provide trainers with a more accurate approach to training than using allocated SZ and judging performance through observation.