I'm wagering that movement of the femur in the hip socket is due to muscle firing down the line toward the big toe joint.
Correlation is not causation!
Why am I picking on this point?
Because I think you can teach it better, to a wider array of skier students, by getting them to focus on parts of the body they are able to consciously manipulate. I return to my original challenge point -- I seriously doubt you can find a skier who will be able to rotate her femur in her pelvic basin's hip joint by firing one or more of the muscles in the image Liquid Feet provided, or by otherwise consciously trying to make her femur rotate in the hip joint. I'm very skeptical about this, obviously. And I am so because I think you can cause a student to injure herself by telling her to do something like this when the ski/boot weight at the end of the leg has so much leverage over the hip joint.
Isn't that how it's supposed to work? It's a ball and socket joint. We have muscles that start in our back and keep connection until they reach our ankles that manipulate the leg and therefore the hip. I thought the muscles in the hip were to keep the ball in the socket? In LF's picture, it doesn't look like there are any muscles that could lift my leg. Tighten or loosen the ball and socket? Yes. You need something like the Psoa's and Quads to move the leg around. I've always thought of the muscles to work like suspension lines; this pulls against that and something is closer. That relaxes and something else tightens and it is further away.
We talk about the thing we see moving the most - i.e. put you finger on your nose. Now how many muscles in your finger dig you use to do that? Probably only a couple and that was to point your finger and NOT to get it to your nose. One of the things that is a pet peeve of mine is when people say "bend the knees" or something of the sort when referring to lateral movements. I had my knees bend laterally . Fist one way then the other. You do NOT want to tell people to do that! The femur rotates inboard or outboard and it is most noticeable in the movement of the knee, so people say point the knee or roll the knee or whatever because that is what they see moving. it is hard to see the femur rotating. If you said rotate your left femur to the right, most would look down at their leg trying to see if something was happening and would be as surprised as the kid dressed as Darth Vader in the VW commercial if it worked.
The knee is a location as is the hip. Things happen there, but since everything is based on levers, the work might be happening somewhere else.