Runners are notorious for tight hamstrings that can cause lower back problems and lead to pulled muscles. Tight hamstrings also limit your range of motion, which can affect running stride, form and speed. To improve hamstring flexibility, try this lying hamstring stretch, which keeps the spine neutral whereas basic toe touches (forward bends) do not, thereby reducing risk of low back pain.
Lie on your back with your legs extended and your back straight. Keep your hips level and your lower back down on the floor. Bend your right knee towards your chest, keeping your left leg extended on the floor.Slowly straighten your right knee, grabbing the back of your leg with both hands. Pull your leg towards your gently while keeping both hips on the floor. Breathe deeply and hold for 10-30 seconds. Repeat on opposite side. To reduce the intensity of this stretch, bend the knee of the stretching leg.