The Idea. These are basically jogging and cycling underwater. In the first case, you wear a flotation belt and have to move forwards with a running motion without touching the bottom of the pool with your feet. In the second, you ride a bicycle underwater, using the water resistance to intensify your workout.
The Benefits. The same benefits as jogging and cycling, but much gentler on your joints and muscles. Moreover, your body is massaged by the water and you eliminate toxins and improve your cellulite as you go.