[coophitter]

The right triceps is active in Hitting and Swinging in humans. Kelley referenced purely mechanical models. The human difference occurs per Kelley's description of drive vs. drag loading. Those two terms describe phenomena that are not similar in nature. An example of the difference would be bashing a tetherball in the opposite direction that its coming at you (drive loading) or quickly pushing it in the direction that its already going (drag loading). There is no switting unless you are fast enough to give that tetherball a full bash in the same direction that it is already moving.