It is very hard to be a good fighter if you aren't loose because moves don't flow if there is tension. I don't like the term "relax" because of the connotation, but you can be very focused and still be loose. That said, Jorge Paez was very loose in the ring.
Alexis Arguello was like Hannibal Lecter when he bit out a nurse’s tongue and his heart rate never raised above 85 beats per minute.