The leg is lifted in front of the body and the heel is rested on a flat surface, with the leg out straight. Keeping the back straight, and the other leg bent, the hands slide slowly down the shin. The stretch is felt in the middle of the hamstring muscle.
The stretch is then repeated on the other side.
Note: Keep your pelvis square on to the surface you are stretching on and don't rotate to the side. Also, by bending the knee slightly, stretching of the upper part of the hamstring muscles is more effective.