Combined Effects of Water Depth and Velocity on the Accelerometric Parameters Measured in Horses Exercised on a Water Treadmill

Abstract

Anecdotal comments of some trainers suggest that exercise on a water treadmill (WT), due to the greater difficulty of movement in water compared to air, increases muscularization and sports performance. Therefore, we studied accelerometric changes in six horses exercised for 40 min on a WT, comparing four situations: without water (DT) and with water at the depth of fetlock (FET), carpus (CAR), at 6 km/h and at the depth of the stifle (STF) at 5 km/h. Another five horses performed the same sessions, but all of them at 5 km/h. We observed that total power (TP) increased from depth DT to FET and CAR, without additional increases at STF depth when the velocity was the same at all depths. However, when the velocity was reduced to 5 km/h, TP decreased at the STF depth. Significant increases in dorsoventral power and dorsoventral displacement (movement of the center of gravity in up-down direction) increased with water depth and velocity. In conclusion, TP during an exercise session on a WT depends on both velocity and water depth, and this power is mainly directed towards the dorsoventral axis. These results should be taken into account when designing a training or rehabilitation plan.