The best way to prevent injuries is to strengthen the muscle groups around those place vulnerable to injuries.
For example, you mention an ankle injury. How much work are you doing to strengthen your calves and feet? An easy way to strengthen your feet is to walk around barefoot. A good way to strengthen your calves is to do regular calf raises. You can start with your toes pointed forward. Then do another set with your toes pointed inward. Then another set with your toes pointed outward. Do this every other day and you will soon be on the way to fortifying your ankles.
But you also have to remember, don't forget about your knees. and your quads and hamstrings. You must have strong legs to be an elite table tennis player. And almost everything in this sport depends on your core! Do not forget to strengthen and stabilize your core. Bird dogs, dead bugs, side planks and glute bridges are all excellent ways to strengthen and stabilize your core. Start off with 10-20 seconds of each, with about 5 sets on each side to begin. When that becomes easy, youtube how to do more difficult variations. I for one, am a huge fan of squats. This is 100% the best way to strengthen your legs (and your core). If you have never performed a squat, i recommend starting with just air squats. Google proper technique for squats, and then film yourself doing a squat. take note of the areas you need to fix to perfect your technique. practice in a mirror before ever considering adding weight). In an ideal world, you would have a more experienced trainer view and correct your technique.
As for your wrist, follow the same methodology- strengthening the hand, and then the forearms and also the shoulder. Thankfully, side planks and bird dogs also work on wrist/shoulder strength+ stability. You could also consider getting one of those devices that have tension and you have to squeeze. they will strengthen your grip, and fortify your wrists.
In summary, here are some exercises you should look on youtube/google and begin adding into your daily/weekly routine (remember the variations are what you do when the basic exercise becomes to easy):
-calf raises + calf raise variations
-bird dogs + variations
-dead bugs
-side planks + variations
-glute bridges
-air squats +weighted squats
--grip strengthening tool
Good luck!
