Since I was a kid, I’ve had outward-turned feet – duck feet. Years of Aikido and dance have helped me to improve my posture, but it’s never gone away. I’ve been experimenting this week with a method that I developed.
When going to bed, get a web-belt, place feet shoulder-width apart, and secure the belt just above the knees. Sleep on your back with feet pointed up. Normally, the feet would be relaxed and splayed out, but with the feet unable to splay out this way, other parts of the body have to accommodate. Outward rotation of the legs is controlled by contraction of the Sartorius muscle, and the inability to relax it completely can cause duck feet.
Improper alignment of the legs will cause tension in other parts of the body, because you are no longer balanced on your skeletal structure, but having to use muscle to stand and move. I noticed tension in my shoulders, upper and lower back. The idea is to relax these during sleep and allow them to stretch.
I have also noticed when I sleep with the web belt affixed this way that I have a tendency to flex my getanden (下丹田) when I shift during the night.
The getanden is the muscle between the navel and the pubic bone. Flexing this muscle is important when doing certain martial arts movements, as it promotes a relaxed upper body, good breathing, and good posture.
So, I conclude that if the Sartorius cannot be fully relaxed, the legs will turn outward. Simply turning them in will pull on the Sartorius and cause anterior pelvic tilt, meaning that your butt will stick out, resulting in more curvature of the lower back (lumbar lordosis ) as you try to compensate. Everything is above continues to build on top of that, so there will be tension in the shoulders and neck.
Gently constraining the legs with the web belt puts the lower body in the right alignment. The Sartorius will be gently stretched as everything else tries to find alignment. Flexing the getanden will then use the extra stretch in the Sartorius to bring the pelvis into vertical alignment, correcting excessive lower-back curvature. This brings the spine into alignment, and the shoulder muscles can relax. I can feel my Trapezius relaxed – I must have been pulling my shoulders up and forward.