I once fought a blind black belt in a Judo tournament. I started off feeling sorry for him and not wanting to take advantage of him, but soon found that he could read my mind and anticipate my every move. Sometimes he would call out something like “That left foot sweep will not work!” He was not really reading my mind, but, since in Judo you move around while gripping the opponent’s gi, he was able to feel sight movements I made that told him where my center of balance was located, which foot I intended to move, and thus which technique I was thinking about using. Skeet shooters do not aim at the target. They compute target angle and velocity, wind speed and direction, weather conditions, etc. and then aim to where the target will be when the pellets reach it. Baseball outfielders do not always race to get to catch a ball before it hits the ground, many times they compute all the factors involved with the ball’s trajectory, and then position themselves to wait for the ball to land in their gloves.
My Taekwondo instructor is national sparring champion. When students asked me how to spar against him, I always told them to keep their guard up and not bother to block. If they kept their guard up, it might stop an attack, whereas, if they blocked a perceived attack, they would probably be wrong in their assessment, leave an opening, and then get hit by an unexpected attack. He was a master of deception. By using minute muscle movements, a twist of the head, a shift in his eyes, a slight shift in balance, etc., he could make you react to a perceived attack and then hit you with a totally unexpected attack. As a result, just as did the racquetball player, he did not have to expend much energy during a match.