Why can’t I squat.

Client presents to you:
On the exam table they have plenty of ankle dorsiflexion range of motion (ROM), full knee flexion ROM, full hip flexion ROM.
You then ask them to perform all 3 together in the form of a squat. The result is that they cannot even squat past parallel thighs. They have used a mere portion of the ranges which they showed plentiful on the exam table. Why ?

Possibilities: The exam showed passive movements, not active loading. Perhaps lack of Skill (unfamiliarity of the skill), lack of coordination (lack of knowing how to put the pieces together), lack of balance and body mass space awareness (ie. where do i put my parts so i do not fall over), lack of hip, knee, pelvis-core stability, etc.

“Just because you have it, doesn’t mean you own it. Nor does it necessarily mean you know how to use it or have the right to push the limits if you have never been there before.”