A bunch of unfit hockey players finds out if supplements produce better results than exercise; professional athlete Mark Richardson reveals the agony behind a positive drugs test and his relief at clearing his name; and John tries to improve his running time with a common supplement banned from the World Anti- Doping Agency's list until recently: caffeine. This programme features the very latest 3D graphics, with an animated character who reveals what's going on inside our bodies when we push them to the limit.