The Movement of the Bar During The Pull and the Jerk


The Movement of the Bar During The Pull and the Jerk

The Trajectory of the Bar During The Pull

Perception of the pattern of bar movement during a snatch or clean is affected by your position in relation to the bar and lifter. If you are watching a lift from the front, the bar will be perceived as moving vertically and evenly, i.e., the bar will be parallel to the ground during the pull. However, if the lifter is viewed from the side, the observer can see that the bar travels backward and forward during the lift, as well as upward.

At first glance, this pattern of bar movement may seem odd. After all, science tells us that the shortest distance between two points is a straight line and that a strictly vertical trajectory will give a projectile its greatest height. It also tells us that once horizontal motion is imparted to an object, the object will continue to travel horizontally until it meets a force that interrupts that motion. These principles clearly suggest that the straighter the pull, the better. However, considerations other than the three mentioned above influence the most effective pattern of bar movement. For example, the lifter's line of gravity travels forward from the heels to the toes during the third and fourth phases of the pull. This generates a tendency to apply a forward force to the bar during the amortization and final explosion phases of the pull. More important, the lifter typically makes contact with the bar at the middle to top of the thighs during the pull. The combination of these factors (which are more pronounced in the snatch) drives the bar forward.

Much work has been done in Eastern Europe and the United States to analyze the pattern of the bar's travel during the pull. (In the United States most of this work has been done by Dr. John Garhammer, who has been active as an athlete. coach and sports science advisor in the USAW for many years.) The evidence provided by this research is quite conclusive in certain respects. It is clear that for most accomplished lifters the pattern of bar movement very roughly approximates the shape of a somewhat flattened S. The bar first moves in a backward curve toward the lifter in the second and third stages of the pull; then and in the final explosion phase, it moves in a curve away from the lifter. Finally, during the unsupported phase, the bar loops backward and down toward the lifter again. The curves traveled by the bar tend to be flatter in the clean than in the snatch. The shape of the trajectory in the pull tends to be much more consistent among lifters during the third through fifth stages of the pull than during the second stage of the pull. During the third stage of the pull, virtually all lifters pull the bar toward the body, during the fourth stage there is almost always some movement of the bar away from the body, and at the end of the pull for a successful lift, the bar nearly always travels in a downward loop backward toward the lifter. In contrast, during the second phase of the pull, many lifters pull the bar toward the body while some pull the bar in an almost perfectly vertical pattern; some actually cause the bar to move away from the body during the first phase of the pull (although this pattern can hardly be considered good technique).

Although the pattern of the bar's movement generally describes the shape of a flattened S, the S can be slanted from the vertical, and its shape can deviate rather dramatically from the curves of the letter S (see Figs. 5 a-c). Figure 5(a) represents the fairly conventional kind of bar pattern, with the overall S-curve being positioned vertically and the curves within the S being rather significant. Figure 5(b) depicts an S-curve in the same general shape, but it is essentially tilted somewhat backward. This type of pattern indicates that the lifter is pulling with his or her bodyweight, and/ or the bar itself, too far back toward the heels at the start of the pull, or soon after the start, and that the lifter is exploding upward and rearward instead of primarily upward during the final explosion phase of the pull. Figure 5(c) shows the bar pattern of a lifter who has the hips very high during the early phases of the pull and who begins with the bar forward of the juncture of the toes and the foot. Such a lifter may produce a curve that tilts somewhat forward and may actually finish with the bar forward of its initial position on the floor.

While studying the pattern of bar movement during a lift can be very useful to both lifter and the coach, it should be remembered that bar movement is more appropriately viewed as an effect rather than a cause. It is true that if the bar moves significantly forward or back of its initial point during the course of the pull, it can cause the lifter to lose control of the bar while trying to fix it in the low position of the squat or split. Therefore, in a sense, it is this pattern that causes the lifter to miss. However, the faulty movement pattern of the bar is only a symptom of improper positioning of the joints of the body and/or the bar and body in relation to one another during one or more preceding phases of the pull. It can also result from improper timing of force application during the pull. These faults must be corrected if the pattern of the bar's movement is to be corrected. This is not to say that it is not possible for the athlete and coach to use the bar trajectory as a means for correction in the pulling style. For example, the lifter could be given feedback on the curve at the top of his or her pull, learn to associate certain feelings with the desired curve and thereby correct the pull. Nevertheless, it is the correction of the positions and force patterns of the body that correct the curve, not the reverse.

It is important to understand that each of the three styles depicted in the illustrations of bar trajectory have been used with success by some very accomplished athletes. The real problems develop when the lifter does one of two things. The first happens when the bar does not travel backward towards the lifter during the initial stages of the pull. Such a bar pattern is indicative of the lifter who begins with the bar too far behind the juncture of the foot and toes, with the combined weight of the bar and body toward the rear of the foot, and who keeps the back too upright or attempts to straighten it too early in the pull. Occasionally, forward movement of the bar during the second stage of the pull is seen in the lifter who begins with the correct balance but shifts the body weight toward the toes and/or uses the arms to direct the bar forward during that stage of the pull.

The lifter who holds his or her torso too upright or tries to straighten it prematurely will tend to have shins that are abraded (although abrasion can occur with lifters who are pulling more of less correctly as well) and will tend to exhibit a lack of both consistency and smooth movement during the second stage of the pull. There will also be a tendency for the bar either to move away from the lifter or to have too little horizontal movement toward the lifter during the second half of the S. This is because the bar is too far forward of the lifter's point of balance during the final explosion for the lifter to direct it back over his or her body by the end of that explosion. Typically the bar will end up over its original position on the platform, the lifter will either jump back or remain in place, and the bar will be left forward of the lifter.

A second major fault occurs when the combined weight of the lifter and bar is shifted toward the rear of the foot to a greater degree or for a longer period than is appropriate during the pull. The result is that the lifter's balance is in the middle or even toward the rear of the foot as the final explosion of the pull commences. In addition, the athlete's shoulders will travel to a position behind the bar earlier than is appropriate. This will cause the athlete to apply a rearward as well as an upward force to the bar during much of the pull. This kind of bar pattern results in a rearward displacement of the bar from the starting point and hence a need to jump back during the squat under in order to be in a position to control and ultimately fix the bar. If this fault is pronounced, it can lead to less consistency in lifting performance and greater stress on the joints and muscles as the lifter attempts to bring the bar under control.
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