A few years ago I dislocated my shoulder at work. Every now and then when I move my shoulder the wrong way (say throwing a baseball) it "sub luxes" or starts to slide out of joint. Luckily it hasn't dislocated again but it can still be painful depending what I do. My biggest worry about practicing aikido was my shoulder bumming out on me however tonight has been the first instance of it happening in two years (and it was slight at that) so I'm not that concerned over it, just bad luck
While I intend to ask someone in the medical field about it, I was wondering of anyone here had any input or advice on how I can strengthen my shoulder muscles to help avoid it slipping out of joint? I would imagine shoulder injuries are common enough in aikido?