Starting Strength

2: The Squat
     
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    The squat has been the most important, yet most poorly understood, exercise in the training arsenal for a very long time. The full-range-of-motion 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.
    The squat is literally the only exercise in the entire repertoire of weighted human movement that allows the direct training of the complex movement pattern known as hip drive – the active recruitment of the muscles of the posterior chain. The term posterior chain refers to the muscles that produce hip extension – the straightening out of the hip joint from its flexed (or bent) position in the bottom of the squat. These muscle groups – also referred to as the hip extensors – are the hamstrings, the glutes, and the adductors (groin muscles). Because these important muscles contribute to jumping, pulling, pushing, and anything else involving the lower body, we want them strong. The best way to get them strong is to squat, and if you are to squat correctly, you must use hip drive, which is best thought of as a shoving-up of the sacral area of the lower back, the area right above your butt. Every time you use this motion to propel yourself out of the bottom of the squat, you train the muscles in the posterior chain.
     

    Figure 2-1. Three views of the squat. Profile view , Depth landmarks for the full squat. The top of the patella (A) and the hip joint, as identified by the apex in the crease of the shorts (B). The B side of the plane formed by these two points must drop below parallel with the ground.

    All styles of squatting tend to make the quads sore, more so than any of the other muscles in the movement. This soreness occurs because the quads are the only knee extensor group, while the hip extensors consist of three muscle groups (hamstrings, glutes, adductors). They comprise more potential muscle mass to spread the work across – if they are trained correctly. Given this anatomical situation, we want to squat in a way that maximizes the use of all the muscle that can potentially be brought into the exercise and thus be strengthened by it. So we need a way to squat that involves the posterior muscle mass, making it operate up to its potential for contributing to strength and power. The low-bar back squat is that way.
    Done correctly, the squat is the only exercise in the weight room that trains the recruitment of the entire posterior chain in a way that is progressively improvable. These are the things that make the squat the best exercise you can do with barbells and, by extension, the best strength exercise there is. The squat trains the posterior chain muscles more effectively than any other movement that uses them because none of the other movements involve enough range of motion to use them all at the same time, and none of the other movements train this long range of motion by preceding their concentric , or shortening, contraction with an eccentric , or lengthening, contraction, which produces a stretch-shortening cycle, or stretch reflex .
    The squat’s stretch-shortening cycle is important for three reasons:
     
The stretch reflex stores energy in the viscoelastic components of the muscles and fascia, and this energy gets used at the turnaround out of the bottom.
The stretch tells the neuromuscular system that a contraction is about to follow. This signal results in more contractile units firing more efficiently, enabling you to generate more force than would be possible without the stretch reflex.
Because this particular loaded stretch is provided by the lowering phase of the squat (which uses all of the muscles of the posterior chain over their full range of motion), the subsequent contraction recruits many more motor units than would be recruited in a different exercise.
    The conventional deadlift, for example, uses the hamstrings and glutes, but it leaves out much of the adductors’ function, and starts with a concentric contraction in which the hips start out well above the level of a deep squat. No bounce, shorter range of motion, but very hard anyway – harder, in fact, than squatting, due to the comparatively inefficient nature of the dead-stop start – yet not as useful to overall strength development. Plyometric jumps can be deep enough and might employ the requisite stretch reflex provided by the drop, but they are not incrementally increasable the way a loaded