Does Muscle Development of Sport Horses Using Water Treadmill Exercise as Part of a Long-Term Training Programme Differ from That of Horses Not Using Water Treadmill Exercise?

Water treadmill (WT) exercise has become a popular tool for equine training and rehabilitation. However, few studies describe the long-term effects of WT exercise in low water on muscle development (MD). This study's objectives were to compare MD changes over a 40-week period in sport horses that regularly used WT in low water within training (Group WTH, n = 55) and a control group that did not (control, n = 28). Subjective MD assessments were undertaken using an adaptation of a previously published method at weeks 0, 20 and 40. For Group WTH, MD significantly increased in the neck, pelvis and hindlimb adductor and abductors between weeks 0 and 20. Neck, thoracic, thoracic trapezius, lumbar, pelvis, quadriceps, hindlimb adductor and abductor, and hamstring musculature increased between weeks 0 and 40. Thoracic musculature only increased between weeks 20 and 40 (p ≤ 0.001 for all). In the control horses, MD did not significantly change between weeks. Regular WT exercise appears to increase MD, particularly for musculature used to create movement patterns seen on the WT. WTs may be appropriate for use under veterinary guidance as part of a directed rehabilitation/training programme to increase core and hindlimb MD.