In the case of deliveries to the head with maximum speed there was evidence of more association in the recruitment of upper thigh and upper body muscles in the initiation of the action within the group of boxers (see figure 4). Again the peak activity of the triceps brachii and flexor carpi radialis were closely coupled in the final phase of the punch delivery. When punch delivery was optimized for maximum speed the muscular recruitment was more variable within the group of boxers, as indicated by the distance from the linear line.The increased mean force of delivery when a punch to the head was delivered with maximal force relative to maximal speed was 1587N equivalent to an additional 38% force delivery. This was associated with an increased level of activity in the rectus femoris muscle of 27% as shown in table 2.