Abstract: A ball pitching machine utilizes a leaf spring coupled by linkage to a ball pitching arm. The flexion of the spring can be adjusted by varying the time of operation of a motor driven spring flexion assembly. Upon the selectable spring flexion being achieved, the user then energizes a ball pitching arm for rotation of the arm through a rest position, a ball pick up position and then to a ball release position. During arm rotation, the arm is first coupled to the spring by a linkage assembly such that further rotation of the arm causes the stored energy in the spring to be released to the arm at a position to effect the ball trajectory. The ball trajectory compensates for the various ball speeds so that the ball penetrates the batter's strike zone. This energy transfer accelerates rotation of the arm to a ball release position, the speed of the ball, as perceived by the batter, corresponding in part to the spring flexion and/or ball trajectory as selected by the user.