[@MelonHead] He never wound up his arm. The palm strike wasn't ever intended to carry power: the emphasis would be only on speed, and winding up would only waste time. Though in the end, we're both stuck with the current chronology, so this discussion doesn't carry any relevance.

EDIT: though i guess there was the act of shifting his weight to the front foot, but this is an action hardly noticeable from a frontal point of view.