Kinematic Responses to Water Treadmill Exercise When Used Regularly within a Sport Horse Training Programme: A Longitudinal, Observational Study.

Simple Summary: Water treadmill (WT) exercise is popular for cross-training of sport horses. The nature of the horse's adaptation to WT exercise could be influenced by the type of session used and how often it is conducted. The study's aim was to compare the gait characteristics of 48 sport horses during a standardised WT exercise test (WT_SET) at the start, i.e., 'week 0', and after 20 and 40 weeks of WT exercise incorporated within their normal training programme. Horses were recruited from the existing client populations of two commercial water treadmill venues for the purpose of this longitudinal, observational study. Measurements of limb, back, poll, wither, and pelvic movement were taken during the WT_SET at weeks 0, 20, and 40. Compared to week 0, the results showed changes in gait characteristics during the WT_SET at weeks 20 and 40 that reflected adaptation to walking in water, including increased protraction and decreased retraction of the fore and hind limbs. Kinematic responses were primarily dependent upon water depth, but previous experience of the horses with WT exercise, the number of WT exercise sessions carried out per month, and the type of the WT exercise session used during training with respect to speed and depth used were also influential. The WT session design and frequency of use can influence the nature of the kinematic responses to water walking seen over time, suggesting that WT exercise sessions within a normal sport horse training programme could be designed in accordance with specific training goals. Repeated exposure to water treadmill (WT) exercise could elicit kinematic responses reflecting adaptation to WT exercise. The study's aim was to compare the responses of a group of sport horses to a standardised WT exercise test (WT_SET) carried out at three time points, week 0 (n = 48), week 20 (n = 38), and week 40 (n = 29), throughout a normal training programme incorporating WT exercise. Horses were recruited from the existing client populations of two commercial water treadmill venues for the purpose of this longitudinal, observational study. Limb, back, poll, wither, and pelvic kinematics were measured during the WT_SET using videography, optical motion capture, and inertial motion sensors. Forelimb and hindlimb protraction increased (p < 0.001 for both), and forelimb and hindlimb retraction decreased (p < 0.001 for both) at week 40 compared to week 0. Caudal thoracic flexion–extension and lateral bend ranges of movement were greater at week 40 compared to week 0 (p < 0.001 and p = 0.009, respectively). Increased training speed was associated with increased craniocaudal poll movement (p = 0.021), decreased forelimb protraction (p = 0.008), and increased forelimb retraction (p = 0.021). In addition to characteristic changes in kinematics due to increasing water depth, regular WT exercise resulted in kinematic adaptation to movement in water. Factors such as the frequency of WT sessions and the type of session used with respect to depth and speed were seen to influence the nature of the adaptation. The results suggest that WT exercise sessions could be designed in accordance with specific training goals when used within a normal sport horse training programme. [ABSTRACT FROM AUTHOR]