A lot of people might be familiar with an achy pain through their glutes that is widely recognised and known as Sciatica. Stretching your hip rotator muscles can relieve this pain in a lot of cases. If you feel this pain, and stretching your hip rotator muscles does not relieve it, it may be because the muscular tension has been there so long that you may need to have a deep remedial massage to the region to release the muscles enough that you can stretch them more effectively for yourself.
This stretch focusses mainly on the Hip Rotator Group of muscles (commonly known as the Glutes, but actually consisting of 9 muscles in 2 layers), but also has effect on the lower Latissimus Dorsi (Lats) and the lower postural muscles of the back (Erector Spinae). There are a few different stretches for the hip rotators, but this stretch combines with the lower back to give a more thorough regional stretch for the hase of your trunk (abdomen ... torso ... whatever you like to call it).
Sit on the floor with your legs extended directly in front of your body. Lift 1 leg, bending the knee, and place that foot on the other side of the leg that remains on the floor. You should now have the foot of the bent leg on the outside of the knee of the leg on the floor. At the same time, twist the lower trunk so you can position the outside of the opposite elbow against the outside of the bent knee. Use your free arm to support your body by placing that hand on the floor slightly behind your hips. This poosition should be comfortable and you should feel relaxed. If you feel a stretch anywhere in your low back or through your glutes, just hold this position as your stretch - following the rules for safe stretching - and build up over time to the next step.
When you are comfortably in the starting position you can start the stretch remembering to feel for the stretch in 2 places - the low back and the glutes. You should feel it almost evenly in both places, but you will probably notice the rotational stretch in the low back first.
Take a deep breath in, then as you exhale gently push your elbow into your knee, remembering to stay as relaxed and supple through your back and hips to allow a deeper stretch. Pushing your elbow against your knee should act as a lever for both regions, giving you further twist for the low back and also adeeper stretch through your glutes.
Hold this position for 15-20 seconds (don't hold your breath), then gently release and repeat on the other side.
Try your very best not to arch or bend your back. The spine should be in neutral for the stretch to be at it's safest and most effective for you. What is a neutral spine? A neutral spine is straight not bent, just as if you were standing. If you hunch your spine,it will change the position of the muscles you are trying to stretch and therefore reduce the effectiveness of the stretch. It may also lead to injury so be mindfull of having a straight spine.
Always remember to relax into your stretches - don't fight against the stretch (it may cause more harm than good), and always do each stretch 3 times, at least twice each day.
Taken from "Stretching Anatomy" by A.G.Nelson and J.Kokkonen - pp 78-79