Tight quadriceps can limit your stride when running and cause subsequent lower back pain. Tight quadriceps are also linked to knee pain. A general method to assess normal quadriceps length is to pull your heel of one leg up to your buttock while standing. If your heel touches your buttocks and you experience no pain, just a mild stretch, normal has been achieved. If this range cannot be achieved, the musculature is too tight and needs more attention. Practical Benefits: This stretch improves stride length and reduces lower back stress. Areas of Caution: Avoid this stretch if you experience lower back pain during or after the exercise. Keep the back in a neutral or straight position to prevent lower back strain.