Starting Strength

forward imbalances are more naturally handled by our anatomy.) You settle into a position of balance when the greatest amount of force is needed to perturb the position, or when the least amount of force is needed to maintain the position. When you stand, this position is where your COM is over the mid-foot, and when you squat down and stand back up, your body’s COM is in balance when it travels in a vertical line directly over this point. Since you will do most barbell exercises (except the bench press) while standing on your feet, this mid-foot balance point becomes a critically important concept in the analysis of good exercise technique.
    Let’s assume that the bar in Figure 2-5 weighs 315 pounds. Were the bar forward of this balance point, it would still weigh 315 pounds, but the effort required to move it through its range of motion would be greater. The eccentric and concentric work done on the 315 pounds would be harder due to the bad leverage position generated by the distance the bar was out of balance. And the isometric stress of stabilizing the load in the bad leverage position adds quite significantly to the effort. Keeping the 315-pound bar directly over the mid-foot through the complete range of motion (ROM) constitutes the most efficient way the work should be done during the lift. When the bar is off-balance, the added energy you must expend due to the leverage of the off-balance load makes 315 much harder to lift.
    It doesn’t take much of an imbalance for the leverage to increase to the point where the rep is missed. Imagine the bar on your back in a position 12 inches in front of the mid-foot as you try to squat; this is an awkward position with even 30% of your 1RM (1 rep max), and the heavier the weight gets, the smaller the imbalance you can deal with. You can easily see that this continuum ends up with essentially zero amount of deviation tolerable at 1RM loads. This concept applies to every barbell exercise where the load must be balanced. So, “good technique” in barbell training is easily and understandably defined as the ability of the lifter to keep the bar vertically aligned with the balance point. The ability to maintain this balanced relationship between the bar and the ground is one of the many things trained with barbells that are not trained in other exercise methods. Since balance is an important characteristic of most human physical endeavors, this is one more reason to base your training on barbell exercises.
    Figure 2-5 also shows the angles we use to analyze the movement of the body under the bar during the squat. The hip angle is the angle formed by the femur and the plane of the torso. Even though the spine is curved when held in the correct position to bear weight under the bar, it is held rigid during the squat, so we can use the concept of “the plane of the torso” to describe the mechanical behavior of this segment under the bar. The knee angle is formed by the femur and the tibia, effectively illustrating the relationship between the thigh and the “shank” (as the lower leg segment is called). The back angle is formed by the plane of the torso and the floor, which is assumed to be horizontal (meaning level , perpendicular to the force of gravity).
    These angles describe the relationships of their constituent segments to each other under the load of the barbell. The back angle is said to be either more vertical or more horizontal , while the knee and hip angles are either more open or more closed . Control of the position of these angles depends on the muscles operating the bones that form the angles. We know that the lifter/barbell system will be in balance when the bar is directly over the middle of the foot, and the heavier the bar, the more precisely this position must be kept. Even if the weight is light enough to remain in a position of imbalance, the lifter will expend more energy than he would if the bar were in balance.

    Figure 2-7. Extra work that must be done on an out-of-balance bar.

    If the bar is on the front of the shoulders, as in the front squat, this bar position will require a very vertical back angle if the bar is to be kept over the mid-foot, as Figure 2-8 illustrates. Notice the knee angle made necessary by this position: it is very closed. And notice the hip angle: it is much more open than it would be with a more horizontal back angle. In this position, the hamstrings are shortened because their proximal attachments on the pelvis and