I'm attending a class at my gym and we are doing a range of motion project concentrating on hamstring flexibility. Lay on your back and raise one leg in the air keeping the other leg flat on the floor. Make sure your raised leg is straight as possible. After a few seconds of stretching, is your raised leg 90 degrees or more from the ground? If so, you're considered to have good range of motion. If not, then a stretching program is recommended. I'm interested to find out how many people can actually do this? I couldn't...I suck!!