The classic push-up comes close to a perfect exercise, challenging multiple muscle groups in the arms, chest, back, and core to build overall functional strength. | Health.com

Original article and pictures take http://news.health.com/2015/10/07/this-50-push-up-challenge-will-transform-your-body-in-30-days/?crlt.pid=camp.zCu3z8YjlrZ0 site