I took a trx class at the gym and liked it. I bought a trx for home to get workouts in more often. Im almost 50 and dont seem to have any core strength but I have high hopes that this will help. Some of the exercises are too hard for me, but it is something to work toward. The app has individual moves and series of moves in workout. My only suggestions would be t1) have beginning, intermediate and advanced levels 2) note how to have good form and what to watch for that may be bad form.
No core about Suspension Strap Gravity Training: Bodyweight Resistance Workout Videos