411 REFERENCE · Wikibooks
Bodybuilding and Weight Training/The Muscular System
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
The purpose of body building is mainly to reinforce the muscular system. When you work out, you tear or wear down your muscles. Your body then uses proteins to build the muscle back stronger so it is harder to tear the muscle again. This is why you must have a proper diet, with plenty of protein, in order to have enough material to build the muscle back stronger.