Previous Exercise on a Water Treadmill at Different Depths Affects the Accelerometric Pattern Recorded on a Track in Horses

SIMPLE SUMMARY: We know a horse has accelerometric and locomotion changes when exercising on a water treadmill (WT) associated with a better performance in dressage and jump competitions. We do not know if these changes are being maintained during terrestrial locomotion on a training track. Therefore, to answer this question, we compared locomotion on a training track before and after WT exercises at different water levels. We have found that the locomotion changes that occur during WT exercise are being maintained during terrestrial locomotion. We have also found some accelerometric evidence indicating that horses with a low fitness level can fatigue after WT, if the water was at a stifle level. This information becomes particularly important when designing a training or rehabilitation program for horses with a low fitness level. ABSTRACT: During a water treadmill (WT) exercise, horses change their accelerometric patterns. We aimed to analyze if these changes persist during terrestrial locomotion. Six horses were randomly subjected to 40 min duration WT exercises, without water (WW), at the depth of fetlock (FET), carpus (CAR) and stifle (STF), with a day off between them. Before and after 30 min after WT, horses were evaluated at walk and at trot on a track with a triaxial accelerometer fixed on the pectoral (PECT) and sacrum (SML) regions. The percent of change from baseline (before WT and after each exercise session) were calculated. Total, dorsoventral, longitudinal and mediolateral accelerometric activities and dorsoventral displacement increased with the accelerometer in PECT but decreased after WT at STF. Velocity increased with the accelerometer in PECT but decreased with the accelerometer in SML, particularly after WT at STF. A reduction in stride frequency was found with the accelerometer in PECT. SL increased with the accelerometer in SML but decreased with WT at STF. Some accelerometric changes that happened on WT remained shortly in terrestrial locomotion. The reduction in some parameters after WT at STF depth seems to indicate fatigue. This should be considered in training or rehabilitation programs for unfit animals.