Starting Strength

principles of force transmission and see how they apply to the power clean.
    It has been mentioned several times, to the extent that you’re probably sick of hearing it, that the elbows must stay straight until the jump occurs. The earlier advice to internally rotate the arms as a reminder to keep them straight was given for this reason. You should know not to bend the arms early, since you have learned this in the deadlift, and the lower part of the power clean is a deadlift. So another reminder: the function of the arms is to transmit the pulling power generated by the hips and legs to the bar. Power is transmitted most efficiently down a non-elastic medium, like a chain, as opposed to a medium that stretches, like a spring. A chain transmits all the power from one end to the other, while a spring absorbs some of the force as it stretches.

    Figure 6-27. Bent elbows just absolutely suck. They are one of the most persistent, hardest to correct, and most detrimental of bad habits that a lifter can acquire. Make it a priority to learn and keep perfectly straight elbows.

When the bar is pulled from the floor with bent arms, the bent elbow is essentially a deformable component, a thing that can straighten out, thus creating the potential for some of the pulling force to be diverted from the bar. Little variances in the degree of elbow bend result in a slightly variable amount of force transfer to the bar and in an unpredictable bar path. The best clean is a highly reproducible clean – exactly the same each time, with each rep a perfect example of lifting efficiency. If the bar path varies with each clean, bent elbows are often the problem. And once elbows are bent, they cannot be straightened out during the pull; that would require the forearm, biceps, and brachialis to relax, which they will be reluctant to do even if there were time for you to think about it and do it.
    Your elbows might bend because you are trying to curl or upright-row the bar with your arms. Your elbows can rotate very fast – blindingly fast, in fact – if the muscles of your arms are relaxed and provide no resistance to the rotation. The very second you tighten the forearms, biceps, and triceps as you attempt to use these muscles to move the bar, you slow the movement down. After you rack the bar, this tightness causes the elbows to stop at the point where these muscles reach the end of their range of motion in contraction, which leaves the elbows pointing down and the bar sitting on your sternum. (This is another good reason to use the hook grip. The hook makes for a secure grip without the need to squeeze the bar with the fingers, thus contracting the forearm muscles.)
    The same force transmission analysis can be applied to the low back. The back is the transmission attached to the hips/legs engine, and force generated against the ground travels up the back, across the scapulas, and down the arms to the bar. If the low back is not locked in hard, absolute extension, it is not as tight as it could be. A round back is a deformable component in the same way that bent elbows are, and it will result in the same unpredictable bar path that is the inevitable consequence of unpredictable force transfer. If form problems are occurring without any set pattern, this might indicate that your low back is not as tight as it could be. Both straight elbows and a solid back position are the basic mechanical requirements of a technically perfect clean.

    Figure 6-28. The spine during the pull should be in absolute thoracic and lumbar extension. Any softness in the chest-up position or lower-back arch reduces the effectiveness of the back as the transmitter of force from the hips and legs to the shoulder blades and on down to the bar.

    As the bar approaches the jumping position, the most important part of the movement occurs. If you are correctly pulling the bar, it is accelerating as it moves up the shins, sliding up your skin or your sweats. As it gets to the middle of the thighs, the trigger trips as the bar touches the jumping position, and you try to jump off the ground with the bar. The reaction with the ground during this explosion produces the impulse that imparts momentum to the bar. The knees, hips, and ankles extend simultaneously, with the knees and hips being the primary contributors to force production. But it is important to understand that the acceleration of the load starts BEFORE the jump actually occurs, and this acceleration results in