What assessments are trainers using for special populations today?

I have been reading into different methods of evaluation and program design lately, and was interested in the different methods trainers and coaches are using today? A lot of this information is so "textbook" in my mind I want insight into the real-world application. More specifically I am interested in special populations like youth, seniors, pregnant women, and those with chronic conditions like arthritis, diabetes, high blood pressure, and others that you may have insight on. I have read a lot of literature on physiologic conditions, implications of exercise, and special considerations for different populations. I am really interested in the assessments chosen and how the results aided successful program design.