Starting Strength

lats.

    Figure 4-18. The human hip, a Class 1 lever.

    This leverage system operates when you deadlift. But if you’re strong enough, the moment arm works the other way, too; the short side moving a short distance with enough force can make the long side accelerate its load over a long distance. This is what happens in a clean or snatch.
    The bar path in a heavy deadlift should theoretically be straight, because that is the shortest, most efficient way to move an object through space from one point to another, and vertically up, because that is opposite to the direction in which gravity is pulling the barbell. Work is defined as force (in the case of work against gravity, the force of gravity acting on the mass of the loaded barbell) multiplied by distance (the measured distance the barbell has to travel), and can therefore be expressed in foot-pounds. Since gravity operates straight down, the only work that can be done against gravity is straight up, and any other movement represents energy expended doing something else. Force can be applied to the bar horizontally – in a direction either forward or backward relative to the lifter – and cause the bar to move forward or backward on its way up, but this horizontal force cannot cause work to be done against gravity. In other words, you can walk around the room with the bar if you want to, but the deadlifting part consists of the work done to change the vertical distance between the bar on the floor and the bar in your hands at lockout. The shortest distance a deadlift can travel is a straight vertical line, and a longer bar path is therefore less efficient. Most sports-related movement – think of judo, downhill skiing, or football – is not as simple as a straight vertical line, but the movements involved in lifting barbells can be, so they should be.

    Figure 4-19. The work done against gravity is purely vertical displacement because the force of gravity acts vertically. Any other movement of the bar is horizontal motion that does not represent work done against gravity and is therefore effort spent inefficiently.

    The deadlift places the bar in front of the legs, creating a different situation than exists in the squat and, to a lesser extent, the press: the bar is not balanced on the shoulders and directly over the mid-foot, with a roughly equal amount of body mass on either side of the bar that can remain in balance during the lift. A deadlift must stay in balance with most of the body behind the bar. This requirement creates a situation in which the center of mass (COM) of the lifter/barbell system must be considered. During the deadlift, this COM will vary slightly, and cleans and snatches are more complicated than deadlifts due to their longer range of motion and increased musculoskeletal complexity. Light deadlifts actually balance differently than heavy deadlifts – the heavier the weight, the closer the loaded barbell approximates the COM of the body/barbell system, and the less important the body mass behind the bar becomes. A light deadlift can therefore leave the ground from a position more forward of the exact middle of the foot than a heavy deadlift can, and the same is true of a snatch or a clean.
    It should also be obvious that the closer the barbell is to the body’s own COM, the shorter the moment arm will be between them, and the less leverage there will be between the components of the lifter/barbell system. The closer you can get the bar to the body’s COM without getting behind the mid-foot, the less leverage between them you must overcome while lifting the load. Any distance between the bar and the balance point at the mid-foot constitutes a moment arm as well, one that has a profound effect on pulling efficiency, as we will see. And as mentioned earlier, the greater the distance between bar and hips, the longer the moment arm is against the hips. So, as is the case with all other barbell exercises that involve standing with the bar in the hands or on the back, leverage is optimal and the bar is in balance when it is right over the middle of the foot. And it should never deviate from this bar path where it is in balance: right over the middle of the foot in a straight vertical line. This bar path should be recognized as the ideal physical model we try to approach; a good deadlifter gets very close.
    The deadlift uses force generated by the extension of the knees and hips to drive the bar off the floor to lockout. The force is