Poor posture is rounding of the head and shoulders placing them forward to their proper alignment. This can contribute to back and neck pain, shoulder pain and headaches.  Sometimes it can have an effect on breathing, heartburn and limit movement of your neck, back and arms. Of course slouching does not truly make us shorter, but long term, it can. If these habits continue throughout your life they can alter the mechanics of how you walk and put strain on your entire body. Elderly adults are often seen hunched over when walking or standing.  This happens from a combination of many degenerative changes and one of them is likely poor posture. So what is normal posture? Normal posture consists of your head being directly above your shoulders and your hips below your shoulders. Your weight should be in the balls of your feet with knees slightly bent.  For more information on posture, check out the link here: http://www.mayfieldclinic.com/pe-posture.htm