In preparation of my 50th (48 now), I've already
switched racquets to a lighter, more powerful racquet, from a K90 to a few different 95+ to SV98+ for now.
Compared to my 30s, the strokes are now more spin, mechanics still the same. Only the serve has changed a little bit from the deep hip lean into the court, to the more upright 'trophy' stance. Serve is now about placement and setup, rather than aces.
Warming up is longer with bands and dynamic stretching, warm downs including a bit of strength training and a lot of stretching.
Off court, I wake up to a 15 minute yoga stretching routine every day. For workouts, I do HIIT 3 times a week (1 heavy and 2 light) and aerobic/cardio of 30+ mins on road/stationary bike or stair climber or running on grass about 4 times a week, on top of hitting 4 times a week for about 2+ hours. I have 1 rest day a week, which is random to how I feel. but no more than 4 every 28 days. Sleep about 7.5 hrs a day, seems I'm need less sleep in one go so having a nap after lunch and before dinner is important.
I'm competitive at UTR12.2, and I find it's easier to do seasonal vs year round training, with build up about 1.5 months before the actual season, then change to light work outs with more court time.
I play for fun and enjoyment, as well as hitting something HARD to offload tension sometimes. I enjoy the artistry of playing now more vs the win only mentality. I don't do meds or supplements of any kind, watch my G.I. intake and eat healthy about 85% of the time.