If you look at flying animals, they usually have small tails. For instance, giant pterosaurs. Now dragons tend to be portrayed with more devloped tails. For my dragons, their tails, and the bony spade at the end of it, is their primary melee weapon.
They usually either try to hit people with the spade (very lethal), or knock them off-balance (non-lethal).
I wanted my dragons to look something like this. Here's the sauce:
Now, dragons can't have much muscle in their tails for several reasons, but I still wanted to give them usable combat moves.
So, how should a dragon's controlled tail swipe be actually powerful without having much muscle?