This report describes the movement characteristics of a three year old boy and girl as they performed a one-handed striking task over a one year period. Observations were made at 4 month intervals as part of a filmed, longitudinal study on the development of motor patterns. The one-handed striking pattern was elicited by asking the children to hit a suspended ball as hard as possible toward a wall. Over a year's time the girl's pattern changed from a) no weight shift to a shift of weight with a step toward the ball, and b) from initiation of the motion with horizontal adduction of the striking arm to initiation of the motion using simultaneous pelvic and spinal rotation. Two major changes observed in the boys pattern were a) progressively longer stride toward the ball and b) a progressively greater pelvic and spinal rotation. (Additional movement characteristics are observed and noted.) (Author/JB)