There are few exercises capable of gently toning your whole body. To achieve this, sit on the floor, legs bent and pulled up against your chest, forehead leaning on your knees. Wrap your arms around your legs so that you can hold them firmly against you, and without raising your head, let yourself roll backwards. Roll on to your rounded back, then, taking advantage of the momentum of the roll, contract all your muscles to return to the original position, without ever raising your head or releasing your legs and arms. Repeat five or six times in succession, then, as you get more used to the exercise, repeat about ten times. You should start to feel the beneficial effects very soon.