High-level competition exercise and related fatigue are associated with stride and jumping characteristics in eventing horses

Abstract

Background: Fatigue and related injuries to the musculoskeletal system are among the most frequent reasons for the withdrawal of high-level eventing horses from the sport. The safety of both horse and rider is very important, and early detection of fatigue is crucial. Objectives: To investigate elite eventing horses in competitive events focusing on biomechanical, cardiovascular and metabolic variables across the cross-country test and to identify their potential associations with fatigue. Study design: Prospective observational exploratory field study. Methods: Observations on 54 cross-country tests of 33 horses at five competitive, high-level events were evaluated using sternal accelerometric analysis of stride parameters between and at the jumps. Blood lactate concentration and heart rate were determined 10 min after finishing. The differences in kinematic parameters between the course start and end were analysed with mixed models for repeated measures. Associations between blood lactate and heart rate recovery with the kinematic variables were quantified with Pearson correlation coefficients. Results: We observed numerous stride characteristics between the jumps and the jumps changing over time during the courses. Blood lactate concentrations were positively correlated with the mean maximal strike power at the jumps in the last minute of the course (r = 0.41; p < 0.001), and the latter was negatively correlated with the mean stride height over the jumps (r = −0.41; p = 0.003). Main limitations: The sample contained horses of varying breeds, sexes and ages, and different horses participated in different events. Conclusions: We identified several kinematic changes during a cross-country test depending on event, speed and fatigue.