Workload of horses on a water treadmill: effect of speed and water height on oxygen consumption and cardiorespiratory parameters.
Authors: Greco-Otto Persephone, Bond Stephanie, Sides Raymond, Kwong Grace P S, Bayly Warwick, Léguillette Renaud
Journal: BMC veterinary research
Summary
# Editorial Summary Water treadmill conditioning has become commonplace in equine rehabilitation and training, yet the physiological demands of this exercise modality have remained poorly characterised until now. Greco-Otto and colleagues investigated how two key variables—water depth and belt speed—influence the metabolic and cardiorespiratory workload in fifteen Quarter Horses, measuring oxygen consumption, ventilation parameters, heart rate and blood lactate across three water heights (mid-cannon, carpus and stifle) and speeds, plus a dry treadmill control. Water depth emerged as the dominant factor in determining exercise intensity, with the highest demands recorded at stifle height combined with maximum speed (1.39 m/s), producing median oxygen consumption of 16.70 ml/(kg·min), tidal volumes of 6 litres and heart rates of 69 bpm—notably, modest speed increments within a given water depth produced negligible physiological changes. The absence of elevated post-exercise blood lactate across all conditions indicates that the tested parameters generated only light-intensity work, challenging assumptions that water treadmill exercise inherently provides high-intensity conditioning. For practitioners, this research suggests that water depth is the primary lever for modulating workload intensity on these machines, and achieving meaningful conditioning stimulus may require depths beyond stifle height or alternative protocols, whilst matching water treadmill prescription to individual rehabilitation or training goals requires careful consideration of the modest intensity these systems typically deliver.
Read the full abstract on PubMed
Practical Takeaways
- •Adjust water height to mid-stifle level when seeking to increase exercise intensity on water treadmills; this parameter matters more than speed adjustments
- •Water treadmill work at these common parameters constitutes low-intensity conditioning; consider this when designing rehabilitation or fitness programmes that require moderate to higher workloads
- •Small speed increases on a water treadmill (within the tested range) produce minimal changes in physiological demand, so focus on water depth manipulation for progressive conditioning
Key Findings
- •Water height had a greater effect on workload than treadmill speed, with oxygen consumption peaking at stifle height (16.70 ml/kg·min) and highest speed (1.39 m/s)
- •Heart rate and tidal volume both increased significantly with water height and speed interaction, peaking at stifle level
- •Respiratory frequency peaked at carpus water level with the highest speed (49 breaths/min)
- •All tested water treadmill conditions produced low-intensity exercise, with no post-exercise blood lactate elevation