Put the phrase "PT exercises" on my list of pet peeves. Calling an exercise a "PT exercise" implies that the principles behind the movements performed during a rehab session are any different than the principles behind any exercise typically found in a strength and conditioning program.
Training and rehab are the exact same thing. The only difference, depending on the individual's particular stage of rehab, is rehab programs are typically the most regressed forms of certain exercises. They are regressed because, when rehabbing an injury, the patient typically cannot tolerate similar loads on their affected joints as they could had they been exercising injury-free. (For example: 1/2 kneeling pallof press is a regressed form of a split squat)
This doesn't change the fact that training and rehab both share common long-term goals of maximizing movement options and building resiliency against daily stresses with graded exposure and progressive overloading.
There is a protective stage early in rehab programs that should eliminate aggravating activities and modify activity to allow affected tissues time to heal. However, during that time, it is important to continue to train in other ways that drive fitness and work capacity without sacrificing the protective stage.
Once the maximum protective stage is over, which for patients who did not undergo surgery can be as quick as a couple of days, rehab should be challenging the patient. In order to elicit change and force the body to adapt, we must inch very close to the threshold of "being hard enough without being too hard." From an evolutionary standpoint, we must put the body in a safe but threatening environment. The body will perceive the stress as being a threat to survival (relative) and will adapt to better tolerate the same stress during the next encounter to prevent death (relative). Too little stress and we do not force the body to adapt. Too much stress and we may experience a setback or unwanted secondary complications.
This is why I believe every Physical Therapist should be well versed in principles of strength and conditioning and capable of writing a general exercise program. Doing 6 weeks of straight leg raises progressing 1 lb ankle weights every week will at best do nothing. Progressing clamshells from a yellow theraband to a red theraband to a green theraband will not drive any desirable adaptation. Doing 10 minutes of reading a book while pedaling a recumbent bike at a snail's pace will do nothing to drive aerobic fitness. This is the image people have of physical therapy because this image exists. BUT THIS IS NOT PHYSICAL THERAPY. And those are not "PT exercises." Those are poorly prescribed exercises performed with minimal to no intent.
The only difference between rehab and strength and conditioning is the expectation of what the patient or client thinks they are signing up for. A patient comes to me with an injury or pain and looks to me for guidance on how to alleviate their symptoms and return to the activities they love. A client looks for a personal trainer or performance coach with fitness or sport-specific related performance-based goals. I look at the relationship of rehab and training like the passing of the baton in a relay race. We are running the exact same race, we are just starting at different points.
Let's stop putting things in buckets they don't need to be put in.