What the Deep Six Hip Muscles Do
The group of hip muscles called the deep six is a set of small muscles, deep inside the hip, that laterally rotate the leg in hip joint. What that means in practical terms is that they turn the leg outward. When, in Pilates or another fitness class, the instructor says "turn your leg out in the hip socket", they want you to engage the deep six. For dancers, these are important "turnout" muscles.
The deep six, in concert with other muscles, are also hip stabilizers and hip extensors. When you walk, for example, the deep six help stabilize and open the hip of the working leg (the one not freely moving forward. When the legs are fixed, meaning that they can't respond to the deep six muscles by turning out, activating the deep six move the tailbone, pubic bone and iliac spine (top, front of the hip bone) up. That is a lifting and decompressing action, very useful to all, especially people suffering from problems associated with hip compression such as bursitis and arthritis.
When you to engage an outward wrap of the thighs in a spiral that lifts up under your butt near your sit bones while keeping your legs in a fixed position, you are taking advantage of the hip opening, and pelvis and spine lifting, qualities of the deep six. Exercises like pelvic curl and shoulder bridge where the legs must stay parallel but the pelvis lifts, sit bones reach for the knees, and the spine lengthens out of it call for this kind of action. Another plus is that the inner thighs oppose the outward rotation of the deep six. Therefore, when you work your deep six, you work your inner thighs.
Where the Deep Six Hip Muscles Are
The deep six get their name because they are deep inside the hip, under more famous butt muscle, the gluteous maximus. They all attach to the inside of the inside of the greater trochanter which is the bulb at the top of your thigh bone that goes into the the hip socket. They fan out to different locations around the low pelvis. Please see the image above.
The deep six hip muscles are, from top of the fan to bottom
- gemellus superior
- obturatur internus
- gemellus inferior
- obturatur externus
- quadratus femoris
Because the deep six are under the gluteus maximus, typically one of the strongest muscles in your body, they are often overshadowed by it. Many people try to get the effect of the deep six muscle action by squeezing their glutes. This can lead to compression around the tailbone and sacrum, and inhibit freedom of movement at the hip. Also, over recruitment of the glutes means over development of the glutes (butt muscles). Learning to activate the deep six can help some people gain the physical awareness that can help them get over "clenching the butt". When you have the glutes and deep six working in balance you have a much better functioning, and probably better looking, hip and butt area.
It is also interesting to note that many lower body nerves thread through and around the deep six muscles. The sciatic nerve, in particular, moves behind the piriformis and an overactive piriformis muscle contributes to sciatic pain in some people.
The Deep Six in Action
I hope this introduction to the deep six hip muscles will help you recognize their action in your own body. Those who would like to know more about the individual actions of each muscles should consult a detailed anatomy book. We train our awareness of the deep six a lot in Pilates. Hip opening with the exercise ball is very good for that. Here are a few Pilates exercises where you might recognize the deep six in action, both turning the legs are turned out, and/or bringing the sacrum forward and decompressing the hip joint:
Anytime you use Pilates Stance or a wide turned out position. For example:
Exercises that use Frog Legs - see frog with exercise band
Footwork Exercises - see: footwork on the mat, standing, reformer and chair.