Movement: From a standing position elevate one foot on a low block or box. Slowly incline forward at the hips, keeping the back neutral and without flexing the lumbar spine. Incline until you feel a good stretch and hold for prescribed time.
Repetitions: Hold for the full prescribed time on one side, then switch sides and repeat. This counts as one set.
Instructions and effects for the Standing Hamstring Stretch exercise 
Movement in Sagittal Plane