An underwater treadmill is a specialized rehabilitation and training device that consists of a treadmill base submerged in a tank of temperature-controlled water. Unlike a standard treadmill, its primary function is to utilize the unique properties of water—namely buoyancy and hydrostatic pressure—to create a low-impact, highly controlled exercise environment. The user walks or runs on the submerged belt while the water level can be adjusted to precisely control the amount of body weight supported; the deeper the water, the greater the buoyancy and the less weight-bearing stress placed on the joints, bones, and soft tissues. This makes it an invaluable tool for early-stage rehabilitation, allowing individuals to exercise and gait-train long before they could tolerate the full impact of exercising on land.