Hi! It's usually a closed tall compartment, wich has a treadmill on the floor. You get your horse inside of it then you turn it on and adjust the speed, so it starts to roll and the horse starts walking in the same place, such as a person in a gym. Then, it slowly starts filling with water until somewhere near his shoulders, and your horse will be exercising walking inside the water.
A water treadmill is basically like a human treadmill and it fills with water while the horse is walking. It strengthens the muscles in your horses legs. A lot of racehorses use it
It fills up like a bathtub to give your horse water therapy and exercise.
It's a treadmill for horses