“Always stretch the hamstrings,” Hock says, “Even if it’s just ankle pumping.” This will help regain flexibility, she adds. This is a passive exercise that is also beneficial to people with back pain. Lay on your back; your spine should be in neutral position. Bend one or both knees. Lift one leg up with the heel toward the ceiling and stretch until you feel it in the back of your thigh. Hold for 15 seconds.