I get tremors too...usually when the pain reaches a level of 9/10 and whenever I do full weight bearing (which means the pain is that high I guess so same thing). They usually last as long as it takes for the pain level to go back down a bit. I've had them less often since I got the TENS unit because for 3-4 months before I got that I was at a 9-10 pain level all the time.