You might assume that the entire unit needs to be submerged in order to reap the highest benefits, but that simply isn’t the case. Typically, you will only need about 3-5 feet of water, and you might be able to get away with even less if you adjust the height setting on your device to the lowest setting. What you are looking for is to ensure that the lower half of your body is completely submerged in water. Many devices use long and exaggerated handlebars that stick up and out of the water to keep your grip firm.