My journey as a long distance runner who started the sport later in life.
So far in physiotherapy (PT) I have regularly endured passive range of motion (PROM) exercises and each therapist has a slightly different technique. From what I have recently read (here), PROM is not a substitute for active range of motion (AROM) movements because PROM does not fire the muscles in your arm the way AROM does. Active muscle firing is necessary to restore balance to joint movements, if I understand correctly.
In any case, my PROMs have been measured weekly and progress has been slow. Even when there are gains in my PROMs I remain cognizant of the fact that my AROMs are much less or non-existent. I still cannot move the proximal and distal interphalangeal (PIP and DIP) joints of my ring and pinky fingers at all. These measurements have been taken on the metacarpal-phalangeal (MCP) joints and the PIP joints of the three affected fingers. No one has ever measured the PROMs of my DIP joints.