what is the idiom doblar los codos really stand for?

Question

one person said it mean study very hard another person said it means to relax

Answer 1

I had just answered this.

It is the same as

hincar los codos = Estudiar con ahínco

to study with eagerness, earnestness, ardour, effort

Answer 2

it means to study very hard , literally translated it would be to bend your elbows and it comes from a time where children took that position, their elbows bend, elbows on the table and hands holding their heads to concentrate on the book they had in front