On-screen combat

Many TV series and movies feature characters that are regularly engaged in combat.
Without any hesitation, people leap into action, delivering powerful, effective, accurate blows.
There is often no real sign of injury afterwards.

Size, strength, physics and even choice of target plays little part in on-screen combat.
Apparently, you can be scrawny, small, weak, possess no combat experience or training and yet still prove victorious every time.