One of the best rehabilitation coaches I’ve ever met is someone who also has no formal education in physical therapy or rehabilitation. In fact, he is a project manager for a security system company in Australia. If I were injured, I’d seek his services before I ever sought the services of a PT, outside of maybe a handful who are associated with the Starting Strength community.
The key to adult learning is repetition. Not having a formal education has advantages and disadvantages. The advantage is you don’t have to relearn and reprogram the ridiculous stuff you learn in a formal education, but the disadvantage is that you are pulling from a deficit in terms of background knowledge. Being a mindful coach who pays attention to their clients, keeps data, is willing to use each client as a learning opportunity, and, most importantly, knowing how to connect with the human aspect of dealing with injured clients (fear, anxiety, withdrawal, etc) will go a long way to make you successful.
If your intention is to learn an encyclopedia full of diagnoses and the “protocol” for rehabbing them, I’m afraid I may have to disappoint you. Rehab coaching is not paint by numbers, nor is it algorithmic. It’s taken me over a decade of doing this as my profession to even get to a point where I have any confidence in myself, at all, to develop a plan for rehabbing an injured trainee.
In cars, there is no replacement for displacement, and in rehabbing trainees, there is no replacement for repetition, so long as it is conscientious assessment and reassessment in the repetitions.