What is the meaning of "to throw out the chest"?
I've checked out lots of meanings with the phrasal "to throw out", but I can't find the meaning. I do not know if this is kind of an idiom.

Thank you in advance!

Question

What is the meaning of "to throw out the chest"?
I've checked out lots of meanings with the phrasal "to throw out", but I can't find the meaning. I do not know if this is kind of an idiom. 

Thank you in advance!

Answer

To put your shoulders back and your chest forward, to make your chest stand out more.

Some people do it when they stand at attention or are trying to call attention to themselves.