Abstract: A device for sensing and indicating movement of a golf player's head adapted to be worn upon the golfer's cap proximate the side of the head, the motion sensor adapted to sense motion of the golfer's head up and down and side to side, the motion sensor device outputting an electrical signal in accordance with movement acceleration sensed to a signal processing unit which generates a variable audio frequency electrical signal in accordance with electrical signal received from the motion sensor, and an audio output device receiving the electrical signals from the signal processing unit, the audio output device being such as an earphone worn in or near the golfer's ear to indicate to the golfer in real time motion made by his head at and during the time that he makes his golf swing.