A cross sectional survey examining centre of pressure and training load in Thoroughbred racehorses in New Zealand
Summary
Musculoskeletal injury is the single largest reason for involuntary wastage from the racing industry. One-third of the Thoroughbred racehorses will be withdrawn from training due to musculoskeletal injury. Therefore, the development of sensitive techniques to monitor a horses response to training may help reduce the risk of injury. A pressure plate is able to quantify balance by calculating centre of pressure (COP) movement during quiet standing and differences in limb loading underneath the
hooves. The aim of this study was to investigate the pattern of the COP in a cohort of Thoroughbred racehorses exposed to different training regimes and stages of a race preparation programme. COP data was measured in 39 Thoroughbred racehorses for a period of one-minute. COP movement was defined as the Total path length (mm), Amplitude (mm) of the COP in mediolateral (ML) direction, the COP Velocity (mm/sec) in ML direction and the Frequency (Hz). The results showed a consistent right limb loading bias irrespective of training load (1408±240 vs 827±234 N, p<0.05). The mean COP Frequency was 0.3 ±0.08 Hz, Amplitude 16.9±12.3 mm and Velocity of COP 1.1±1 mm/s. There was a linear relationship between Amplitude (mm) and total COP path (mm), R2=0.58, p<0.05 and Amplitude and velocity (R2=0.59, p<0.05). The relationship between Amplitude and Frequency was moderate and curvilinear (R2=0.28, p<0.05). Furthermore, there were two distinct groups based on training load (0-10 gallops vs. >10 gallops). Horses with >10 training gallops had smaller COP Amplitude (10.5 (IQR 7.22-17.42) vs 21.7 (IQR 11.61-29.26) p<0.05)). There was less variation in velocity in the >10 gallops group, but no difference in mean velocity between the groups. The unloading of the left limb may be present irrespective of the training load. Furthermore, the reduced amplitude may be associated with greater muscular tone due to greater training load.