Question- Goniometry

Hey guys! im physio student but need some help...
i have a question re goniometry i was asked in an exam that i was'nt able to answer,and Id really like to know the answer. So with active and passive goniometry..when done passively by physio the patient reached says 120 degrees hip flexion but actively reaches only 112 degrees..why is this so? what is stopping patient reaching full range themselves? What does it say about patients condition?

Thanks :)

If passive range is greater than active range it would suggest that there is no physical barrier to movement from the joint itself. Thus a reduction in active range would perhaps be due to muscular weakness. That could be due to disuse, attrophy, nerve conduction problems etc. It's really Physio 101 in terms of the basic assessment to help dissociate between joint vs musculoskeletal issues. Then based on that information you would begin to look at manual muscle testing to see if in fact the muscle associated with that joint range of movement is testing on the weak side.

Hope that helps your understanding.