Workload of horses on a water treadmill: effect of speed and water height on oxygen consumption and cardiorespiratory parameters

Abstract

BackgroundDespite the use of water treadmills (WT) in conditioning horses, the intensity of WT exercise has not been well documented. The workload on a WT is a function of water height and treadmill speed. Therefore, the purpose of this study was to determine the effects of these factors on workload during WT exercise.Fifteen client-owned Quarter Horses were used in a randomized, controlled study. Three belt speeds and three water heights (mid cannon, carpus and stifle), along with the control condition (dry treadmill, all three speeds), were tested. Measured outcomes were oxygen consumption (V̇O2), ventilation (respiratory frequency, tidal volume (VT)), heart rate (HR), and blood lactate. An ergospirometry system was used to measure V̇O2 and ventilation. Linear mixed effects models were used to examine the effects of presence or absence of water, water height and speed (as fixed effects) on measured outcomes.ResultsWater height and its interaction with speed had a significant effect on V̇O2, VT and HR, all peaking at the highest water level and speed (stifle at 1.39 m/s, median V̇O2 = 16.70 ml/(kg.min), VT = 6 L, HR = 69 bpm). Respiratory frequency peaked with water at the carpus at 1.39 m/s (median 49 breaths/min). For a given water height, the small increments in speed did not affect the measured outcomes. Post-exercise blood lactate concentration did not change.ConclusionsVarying water height and speed affects the workload associated with WT exercise. The conditions utilized in this study were associated with low intensity exercise. Water height had a greater impact on exercise intensity than speed.

Consensus for the General Use of Equine Water Treadmills for Healthy Horses

“…If faster speeds are selected, water depth should be decreased and the gait quality and posture of the horse re-assessed as water depth is incrementally increased. It has previously been shown that increasing water depth has a greater impact on the workload of water treadmill exercise than increasing walking speed [ 19 ]. The greatest workload (as measured by oxygen consumption and heart rate) was found to occur at 1.39 m/s in water at the depth of the stifle.…”

Microdamage in the equine superficial digital flexor tendon

“…However, the specific effects of different water-based exercise on SDFT stresses and strains are yet to be determined. Previous studies suggest that water treadmills and water walkers are classed as low-intensity exercise, 127,130 while swimming and ridden 'surge' training may be a form of relatively high-intensity exercise. 126,131 Therefore, water treadmills and water walkers may be suitable at an earlier stage of the fittening programme before ridden work commences.…”

The use of the water treadmill for the rehabilitation of musculoskeletal injuries in the sport horse

“…Greco-Otto et al . (10) documented that horses exercised on a WT at different depths work at exercise intensities of 27.7–32.7% of their maximal HR, reflecting its aerobic nature.…”