@ninjadork
Don't want to get into your dispute, but as a martial artist myself, I can say that you're correct, at least from a practical point of view. Modern martial artists rarely break bricks, planks and stuff since nowadays with the spread of physiological knowledge everyone understands that this is definitely unhealthy. Even though, anyone who punches or kicks a sand bag regularly, can assure you that if the hit is successful, you won't get pushed back. And the more you train, the more force you can apply to a sand bag, but you'll notice that the recoil doesn't really increase that much. Proportions aren't direct at all. Obviously, it gets physically harder for your body, but you're not pushed back if enough force's been applied, like you stated.
Now if he was in space, that'd be a different story, but as has been noted, the only way for him to stay in air is to have velocity. The fact that the story is told using still images doesn't mean that objects in it are still too.