To perform a hamstring stretch, start in a seated position with the left leg extended straight forward, toes pointing up. Bend your right leg and place the sole of your right foot along the knee or inner thigh of the left leg. Reach forward toward the toes of the left foot until you feel the hamstring stretch (your hamstring muscle is on the back of your thigh). Hold for 10 to 30 seconds without bouncing.
Switch legs and repeat. This stretch is sometimes called a hurdler's stretch since it mimics the position of a runner's legs as she jumps over a hurdle.