Why bother sitting up straight?

Why bother sitting and standing up straight? 

Well, when you slouch, the only thing holding up your head is the upper traps. The average human head weighs 8 pounds, and when your upper traps are forced to hold it up without help, they become overworked, tightening and shortening in response to the constant overload. It’s like the difference between ten women trying to lift up a car versus one. All that weight was never meant for a single body to hold.

Fortunately, the solution is pretty straight-forward—fix your posture! Proper posture ensures that all the right muscles are engaged, and the upper traps aren’t working alone to hold up your head.