Why is it important to keep your back and neck straight while performing a hamstring stretch? a. you can't touch your toes with your neck and back bent. b. arching the neck and back puts stress on the spine. c. bending the back turns this into a spine stretch. d. the hamstring is only stretched when the back is straight.

It important to keep your back and neck straight while performing a hamstring stretch because Arching the neck and back puts stress on the spine   (option B)

Explanation;  

The hamstrings are a group of muscles that are located at the back of the thigh. It runs from the pelvis to the shin bones. It also includes semitendinosus and semimembranosus and biceps femoris, they can effect tilt of pelvis as well as hip joint and knee joint.