AROM NO – PROM NO
The second scenario we encountered was that neither AROM nor PROM are possible. Chances are that this is not an agonist problem now.
To find out what is happening, the therapist has to check for the endfeel of the movement.
To distinguish between intra-articular and extra-articular blockage, check the quality and feel of the blockage within the joint. If the blockage has a rubbery feel and gives slightly under pressure, it is likely to be an extra-articular (soft tissue) blockage. If the blockage seems inflexible and range of motion ends abruptly, there is probably an intra-articular (bony) blockage.
The Short Formula
If the client cannot perform Active Range Of Motion (=AROM NO) but you can perform Passive Range Of Motion (=PROM YES) then you are likely to look at an agonist problem.
In Short
AROM NO and PROM YES ==> Agonist muscle
AROM NO and PROM NO ==> Antagonist muscle / fascia or Joint
Shorter still
NO YES = Agonist
NO NO = Antagonist or Joint