That would be a separate thing then, no?
Anyway, while jumping, you can still check for the 'position' in order to detect collisions - top Y position of the shadow, for example. If it matches with the victim's shadow position (within range), the FALCON PUNCH would land into delicious meat. That's so you can't kick your opponent's head while you're on top side of the room and he's on bottom side, when their sprites overlap.
Yeah, you've gotta think of all situations like that and decide what is the best solution for you.