Sports giants Reebok recently brought out a range of trainers designed to improve toning in the legs and bum. They called the range ‘easytone’, which spanned from the concept of the shoe. The trainers are designed with a convex sole which creates instability; it forces the foot to balance on a smaller surface area than usual. This means the leg is constantly trying to find a balance point and keeps the muscles working on a small scale, even while walking.