Zitat von Starting Strength
Elbows
An understanding of elbow position is essential for lifting efficiency and, once again, safety. The elbow represents the distal end of the humerus, as it articulates with the radius and the ulna (distal is the end furthest from the center of the body, and proximal would be the closest to it). The pecs and delts attach to the anterior side of the humerus up by the shoulder, and the triceps attach to the olecranon process, the pointy part of the ulna that forms the outside of the elbow.
Essentially, all the force being generated by the muscles involved in the bench press moves the elbow. The action around the shoulder joint contributes to the movement of the elbow, but the shoulder doesn't, or at least shouldn't, change its position against the bench while the humerus is moving.
The position of the humerus while it moves the bar is crucial to the success of
the movement. This position is determined by the angle the humerus makes with the
torso, as seen from above. An angle of 90 degrees to the torso would have the arm at
right angles to the bench, parallel to the bar, a rather extreme position. The other
extreme would be allowing the elbows to come down to a position parallel with the
torso, with the arms sliding against the ribcage at the bottom. The preferred
position will be somewhere between these two extremes, but higher rather than lower.
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The bar follows the elbows: if the elbows rotate up away from the ribs, the bar goes up the chest toward the throat, and if the elbows slide down toward the ribcage, the bar moves down toward the belly.
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Elbows more in line with shoulders is important because the distance between the bar and the shoulder forms a lever arm against the
shoulder. The greater the distance between the bar and the joint that is driving the bar, the more torque against the joint with the same
weight.
