Hey Chris, it is very common to see hip internal rotation mobility deficits in this 90/90 position. A lack of hip internal rotation mobility will also limit squat depth.
In some people, this limitation is due to the structure of their hip socket and doesnāt change much with exercise or stretching.
To improve this mobility deficit, since it is related to the hip joint capsule and surrounding connective tissues, the key is to perform low-load long-duration holds in the restricted positions. This means taking the hip to the point of restriction and just before cramping and then to hold for 2-10 minutes. Joint tissues require long holds to slowly adapt and change. Does that make sense?
Here is a YouTube video where I cover these in more detail.
Replied on Help - Hip Assymetry and Unflexible/...
30 Apr 13:41
Nice! Iām glad the video was helpful.