system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do pull-up bars not break the doorframe?

I'm guessing it has something to do with leverage, but wouldn't enough weight just crack the doorjamb off?
gpt
Enough weight would, yes.

Doorframes are typically made strong enough to handle this for reasons not related to pull-up bars.

Security is the most obvious - but it is at some point hard to construct a house that is fragile enough for it to be a problem without it actually costing more.

Commonly used construction practices mean most doorframes can handle the load, without being specifically designed for it.