Eli5 Why are some muscles, like a bicep, easier to flex than other muscles, like a deltoid (shoulder), when the deltoid can lift much more?

Question

Eli5 Why are some muscles, like a bicep, easier to flex than other muscles, like a deltoid (shoulder), when the deltoid can lift much more?

In: Biology

Answer 1

This. My lifting partner and I were trying to figure out how to “flex” our delts (which we were not successful at doing).

Please science, help.