Correlation of competition performance with heart rate and blood lactate response during interval training sessions in eventing horses

Abstract

Objective performance monitoring in eventing horses is rare as the implementation of standardised exercise tests is commonly perceived to interfere with the daily training routine. The validity of performance parameters derived from GPS data, heart rate (HR) and post exercise blood lactate concentration (LAC) measured during usual training sessions should therefore be evaluated. Velocity (V), HR and post exercise LAC recorded during 172 interval training sessions in 30 horses were retrospectively analysed. Linear regression of HR, averaged over retrospectively defined speed ranges, was used to calculate the V at HRs of 150 (V150) and 200 (V200) beats/min. A single exponential regression model, fitted to LAC in relation to HR values from the whole group of horses, was used to predict LAC for each horse’s individual HR value and to calculate the difference between measured and predicted LAC (LACdiff). Recovery HRs were derived from bi-exponential regression of HR decrease after exercise. Results were compared between different stages of training in the same horses and between horses categorised as superior (SP) and average performer (AP) according to their competition performance. V150 and V200 significantly increased with progressing training. SP had higher V150 and V200 values, lower LACdiff values and lower HRs after 1 min of recovery (HRR60s) than AP. Competition performance was positively correlated to V150 and V200 but negatively correlated to LACdiff and HRR60s. Regular monitoring of HR and LAC in response to interval training provided valuable indicators of performance. The results of this study may contribute to an increased applicability of routine performance monitoring in eventing horses.