Interesting that you ask :-) We use to discuss injuries all the time. The objective was to get as much on the ball as possible but not be so radical that our careers would be over by age 40.
First, everyone was throwing 16 pounds. Secondly, nobody had a really high back-swing. Just about everyone tucked their little finger. Our wrists were cocked and our hand was way under the ball with our thumb way right. At the point of release, it would all come unwound. A good analogy would be the motion used to start a lawnmower with a pull rope :-)
Most of my friend ended up wearing wrist braces and forearm straps to unload the stress later in their lives. I still get an injury I've never had diagnosed. My wrist gets really sore dead in the middle. I usually just wear an ace bandage or my bowling glove for a day or too and ice it 2 times a day for at least an hour.
Since going back to 15 pounds, I don't get that injury, but the extra weight can make all the arthritis in my right hand flare up when the weather changes.
At age 70, I can still get 325 RPM's on a good day with 15 pounds. However, it's all catching up with me. I usually only wear a glove when I'm injured. Going to start wearing one more often to prevent injury instead of after I've already injured myself.
This summer, against all logic, I plan to try and throw the ball 2 handed. Nobody my age is doing it. I have trouble bending because of back surgery and that may be something I need. But, my delivery has been so compact for so long, throwing with 2 hands won't be that different. I plan to use weak equipment so I get as much speed as possible. I'll shoot spares one handed. Speed will be the determining factor. If I can't throw fast enough to offset the increased RPM's, I'll discontinue the effort. Or if my back can't handle the load, that will end the effort also.