Lie on your back with your knees bent. Keep you feet flaat on the floor. Grasp your thigh the knee and slowly pull it to your chest. Keep your back flat against the floor. You will feel pulling in your buttocks and low back. Hold for a few minutes switch legs and repeat exercise. Another - lie on your back. Lift your leg.. Place your hands around your thigh, just above the knee. Then tighten your abdominal muscles. Pull your leg toward your chest until you feel pulling in the back of the leg. Gently straighten your leg as much as you can. Hold for a few seconds, switch legs and repeat exercise. Another - lie down and bend both knees. Press your low back into the floor and tighten your abdominal muscles. Hold for several seconds then relax. Repeat several times. There are more but I won't include them all. Let me know if you try them.