@coco8 Wow, I'm sorry your son in law needed this surgery, but circulation is important. My circulation is affected by TOS and my hands used to turn blue or purple and get cold to the touch. Just turning my head cuts off circulation. That is better now, but I can see where that type of situation would be made worse by the extra muscle development of being a gymnast. How is you son in law now? How long has it been since his surgery? Did the surgery help, and did it affect his normal functioning? I presume that he had to give up gymnastics by loosing part of a collar bone and the function supporting strength of it.