system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does pedaling up hill feels harder than walking up the same hill?
gpt
The thing nobody is mentioning is power

You walk slower than you pedal. 

Even if the bike was weightless, pedaling makes you go faster than waking. And that translates in more power being delivered. That feels hard

With the proper gears, you could pedal at waking velocity and it should be as hard as waking. 

Other than that, there is a matter of geometry of the pedaling vs walking. Different muscle groups and such.