Hip Flexion, Hip Flexion or Hip Flexion?

Jul 25, 2022

Weird title isn't it. Looking at rehab programs always gets me thinking. At MBSC we get to see the rehab protocols from some of the big shots in the world of surgery and I am often amazed how poorly designed they are. It goes back in many ways to the difficulty in language that we often encounter in strength and conditioning ( link to No Habla Strength and Conditioning) . One area that particularly perplexes me is the inter-relationship  of squatting and hip flexion. One prominent rehab concept for patients undergoing hip arthroscopy says that squatting musty must be limited to seventy degrees of knee flexion. However, when I asked a therapist why, he actually said the intent was to limit hip flexion by avoiding deep squats? So here is my question. Are we only trying to limit hip flexion in concert with knee flexion i.e squatting and , why? I don't claim to know the answer, only to have the question. I'm hoping we can get a forum thread discussion that will help all of us.

Here are three scenarios:


This video above shows hip flexion greater than ninety degrees with the leg unloaded.

This picture video is hip flexion of greater than ninety degrees with the leg loaded through the knee and hip. Obviously the forces are different but why?  


What occurs in video 2 that creates a precaution not needed in video 1 above?

Lastly, lets look at another video of hip flexion to ninety degrees. 


Why is ninety degrees of hip flexion with the leg straight okay but not with a bent knee.

One thing we know is that squatting causes FAI type pain but, that standing hip flexion and the hip flexion of the SLDL don't. Is what we are trying to avoid joint loading vs joint angles? Another thing we know is that bilateral squatting is often more painful than unilateral versions?

Hoping for some really good forum responses.