In reply to neuromancer:
> Cold therapy constructs the blood vessels, preventing blood from getting there. Hence why you use to it prevent bruising.
Yes, if you're sitting in an ice bath. No, if you're comfortably warm and place only your hand in ice water:
After a few minutes of constricting the blood vessels your body realises that only your hand is cold and it does not need to protect the core. After that painful time has passed, the blood vessels in your hand dilate to protect it from cold damage and your connective tissue gets a useful boost of blood flow. Then when you plunge your hand into hot water, further expansion occurs and infuses still more blood into the tissue. Repeat several times and you are effectively pumping blood (i.e nutrients for repair) into your connective tissue.