I take it no one read the Reg article about how Sex may be the culprit in Carpal Tunnel Syndrome, not typing?
Not quite RSI, but perhaps linked?
But seriously, to make a brief (well, sort of) mention of the brainjack idea. A halo that can interpret thought it nice and all, but a brainjack into the brainstem will allow total Nervous System interception. When you run in your VR world, you don't have to be physically running, so the BrainJack2000(tm) filters such actions from passing along your spinal cord. Of course, it would need to be positioned above the lower brain so breathing and such isn't affected (or better hope the ipchains/tables people got their filters correct!). There is the added benefit of the brainjack being capable of SENDING information back to the brain. Neurofeedback and the like. Kick a rock? Make you feel like you kicked it. Of course, more ipchains/tables to sort out to prevent rogue software from sending a "you're being burned alive" signal.... Perhaps have a sliding scale of pain and such you would like to be let through, like adjusting volume.