Originally Posted by Transcendental
I'm not a doc, but in terms of squatting usually a few things occur if structural abnormality is ruled out. No one can rule structural issues out except a doctor, complete with xrays, so don't let anyone on the internet tell you otherwise. You are right in that some people really are not meant to squat (shalllow pelvis, different shapes, etc.) This makes me cry inside, as I think everyone should have access to one of the greatest things on the planet.
Where do you have pain? Front hip, near/under groin, near the SC joint, on the outside of the hip (trochanteric hip, the bone that sticks out on the side of your hip)?
How much internal rotation do you have in the femur, during knee flexion. External? These things rule out many possibilities. Are you having muscular pain, or joint pain? If it's the latter, stop and reassess immediately.
Also very possible, but again can only be confirmed by xrays and MRI's, but doctors usually only order these if you are feeling pain from a labral tear, you might have to just specifically ask for a scan of some sort to rule it out. I had surgery 3 months ago for this issue, and had my left femur head shaved and my labrum repaired. I was squatting (in lbs) 420 and C+J 315, Snatch~265. I also have the condition in my right hip (nonsurgical) but to a bit of a lesser extent, so all this hip flexion and deep squatting was just not good. The research is not conclusive to whether or not this condition is purely genetic but it is quite likely influenced by my days playing offensive line, 50% of my day was in explosive hip flexion and extension.
People with FAI should honestly avoid ALL squatting movements, as disheartening as that sounds. It is quite common in Hockey players, and most of those trainers agree about avoiding bilateral movement. Single leg movements allow more pelvic movement in a healthy manner. Can you do deep lunges while feeling it in your glute max, and glute med (side of butt) without pain?
Again this is why I ask about your internal rotation and external rotation. Superman type activities are good for learning the good "feeling", but if those help that usually implies some lack of strength in glutes. If you lack IR, your glute med should be your first priority, as you cannot deep squat without adequate internal rotation. Without internal rotation (30+ degrees) it is likely that your hip if hitting an artificial end range, and that pain you are feeling is your bone placing friction on your cartilage. Not trying to scare anyone, but of course I don't want people to suffer like I did. Rehab process is long. Right now all I look forward to is the burn from banded side walks and 90degree leg presses.