A training device for throwing a baseball includes a plate assembly that is pivotally connected to a support member. The plate assembly includes a flat, rectangular balance plate and a sleeve disposed transversely across the bottom surface of the balance plate. The support member includes an elongated support arm on which the sleeve is adapted to teeter and a generally T-shaped strike plate connected to the support arm. In use, the training device can be used in the following manner to train a pitcher to exert maximum rear leg drive while throwing a baseball. Specifically, the training device is disposed on a flat, level flooring surface such that the plate assembly teeters on the support member. The pitcher then centers his rear foot on the balance plate and lifts his front knee. At this time, the pitcher drives his rear knee forward until the balance plate pivots forward and contacts the strike plate which in turn generates an audible signal. With the majority of the body weight of the pitcher displaced behind his rear knee, the pitcher begins his delivery. Because the pitcher is able to use the majority of his body weight to power his delivery, the pitcher is able to throw the baseball with greater velocity and with less strain exerted on his pitching arm.