There are dozens and dozens of websites devoted to performing arts health - in particular, on overuse injury, repetitive strain injury (RSI), and the like. Here are a few to get you started (but please note, none of these are endorsed in any way).
RSI and Overuse Injury Association of the ACT - The only Australian society devoted to RSI/overuse?
Dutch RSI Association
Musicians and injuries
RSI-Relief - Repetitive Strain support and recovery
Australian Society for Performing Arts Healthcare - A recently-established national organisation