The full-range-of-m otion exercise known as the squat is the single most useful exercise in the weight room, and our most valuable tool for building strength, power, and size.
Mark RippetoeStrength is an excellent example of a physical characteristic that drives improvement in other athletic parameters. More strength means more power, more endurance, better coordination, and better everything else. This is why, all other things being equal, the stronger athlete is the better athlete.
Mark RippetoeYou do not need to do many different exercises to get strong - you need to get strong on a very few important exercises, movements that train the whole body as a system, not as a collection of separate body parts. The problem with the programs advocated by all the national exercise organizations is that they fail to recognize this basic principle: the body best adapts as a whole organism to stress applied to the whole organism. The more stress that can be applied to as much of the body at one time as possible, the more effective and productive the adaptation will be.
Mark RippetoeA squat cannot be performed on a Smith machine any more than it can be performed in a small closet with a hamster.
Mark Rippetoe