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By Root 596 0

of leverage, the total contribution of the lats, teres major, and triceps averages out to approximately the same as just the lats. When the shoulder is in front of the bar and the back angle is stable in a pull, the angle of attachment between the lat and the humerus is about 90 degrees, since this is the angle at which the least muscular force is required to produce a rotation force that is equal and opposite to the weight. It is the angle at which these muscles can exert their tension on the humerus most efficiently and thus provide the maximum force transfer and stability during a pull from the floor in which the bar needs to stay over the mid-foot and as close to the hips as this stable “hang” will allow (see Figure 4-25). And the back angle adjusts to produce the 90-degree lat angle in equilibrium between the shoulders and hips.

The fact that several muscles are contributing to this posterior pull makes the angle hard to calculate precisely, and some variation with anthropometry would be expected, but the lats appear to be the major factor in the system, and the angle of attachment in a stable configuration is probably very close to 90 degrees. What is absolutely clear is that through the bottom of the pull, there exists a back angle in which the shoulders are in front of the bar, the arms do not hang straight down, the hips are closer to the bar than they would be if the arms did hang straight down, and pulling the bar off the floor in this position results in a vertical bar path. With this path, the lifter can most efficiently maintain the balance point over the mid-foot and use the lats and related muscles to maintain a vertical bar path.

Stated more succinctly, the arms are not plumb in a deadlift because the lats do not attach to the arms at 90 degrees when the arms are plumb. The arms must slant back to achieve a position of stability as they hang from the shoulders. So the body must assume a position that allows the arms to be at 90 degrees to the lats and for the bar to be pulled in a straight vertical line off the floor. If the hips are too low, the lat attachment angle will be less than 90 degrees, and the hips will rise as the back angle adjusts to the stable position. If the hips are too high, the angle is greater than 90 degrees, and the lifter cannot as efficiently prevent the bar from continuing forward.

Figure 4-25. A proof of the theory that the lat stabilizes the humerus most efficiently at 90 degrees, from our friend Matt Lorig, Ph.D. This is the kind of analysis you get when you ask a physicist to think about barbell training.

Figure 4-26. The skeletal relationships in the pull off the floor with arm angles of 90 degrees (I), < 90 degrees (II), and > 90 degrees (III).

The reference angles used in analyzing the deadlift are the same as those used in analyzing the squat. The hip angle is formed between the femur and the plane of the torso. The knee angle is formed between the femur and the tibia. The back angle is formed between the plane of the torso and the floor, which is assumed to be horizontal. In a correct deadlift, the knees extend as the bar comes off the floor, indicating that the quadriceps extend the knees under load. The back angle should be constant until the bar approaches the knees; the hamstrings “anchor” the pelvis so that this angle can be maintained (more on this later).

Figure 4-27. The three reference angles: knee angle, hip angle, and back angle.

The hip angle opens up only slightly as the tibias get more vertical. As the bar approaches the bottom of the knees, the back angle – and consequently the hip angle – begins to change significantly (Figure 4-28). Some people start this transition at mid-shin, some higher, as there appears to be quite a bit of individual variability in the precise position of the beginning of this shift. Anthropometry is probably an important variable; arm length, for example, obviously influences this balance relationship. In most snatches and cleans, this back-angle shift appears to start a little higher up the tibias – very