I wonder what they do to stop muscle atrophy. I remember learning way back in elementary school that there's risks with joints and the ligaments and tendons that were considered mostly impossible to mitigate. As far as not responding well to returning to gravity after a prolonged period, I mean. I don't know what's the longest anyone spent in space back then, so I don't know if that was theory or empirical fact.
At any rate, I hope they're all physically able to resume normal life in short order with no long term consequences.