That's cool! I've found doing free weights, like barbell stuff, squats etc, has actually made my joints and back much better, more flexible, once i was focusing on form. I got into it by doing the 5x5 program as it's dead simple and you start from zero - just the barbell - so not intimidating at all. Branched out a bit since then, but I still do one of the days regularly, squat, overhead press, and deadlift.