Currently dealing with something that I assume is Tennis Elbow on my back arm. Never had that before so I have no clue if that's what it is. Bit painful from time to time and slowly getting worse, but hasnt hindered my playing ability... or lack there of... yet.
Back in the late 90s, I was hitting over 500 balls per day, and playing a lot of 9-ball. I developed ‘tennis elbow’ (tendonitis), which I blamed on the violent forces necessarily involved with an effective break. I ran into Dallas West about then, who was dealing with the exact same issue. His wife recommended regular ibuprofen, but it caused me gastric distress. I also tried cortisone injections, but any beneficial effect was only temporary. I stopped breaking 9-ball, but the ‘repetitive motion’ damage already done was so severe, even playing 14.1 was too painful, so I gave up the game.
My elbow healed over the years, and I recently started playing seriously again, only to discover that now (with failing eyesight), my ‘prime years’ have likely passed.
As a result, I believe the rules of pro billiards should likely change, in order to discourage those who must practice/apply so much force when breaking in order to be competitive, from repeating my negative experience (?).