A new article about pulling mechanics

[shanuea]

Nice article Steve/Mark. It will take me a second read to digest it completely.

[Tamara Reynolds]

And about modern technique... right in the level 1 text it says that at the start the shoulders should be in front of the bar. It is widespread, so universally believed as to be almost beyond discussion, that the knees move back out of the way of the bar as the bar is pulled up...

And about modern technique... right in the level 1 text it says that at the start the shoulders should be in front of the bar. It is widespread, so universally believed as to be almost beyond discussion, that the knees move back out of the way of the bar as the bar is pulled up...

And finally... I think the continued insisting that the "acceleration" or second pull, or jump, or whatever you call it, starts at or near the knees, or anywhere much lower than the hip is crazy given the very easily verified case that the bar stops accelerating, and even often slows, as it comes up the thigh and the second knee bend occurs... setting the lifter up to "explode" from the hip.

First of all, I think that it should be noted that Rip is a weightlifting coach and has been for quite a long time.

Second of all, are you actually quoting the USAW Level 1 text as gospel? Because that is hilarious. What SHOULD happen and what actually DOES happen aren't always the same thing. That is the point of this article, whether or not people agree about what should happen. Should the knees move out of the way on the first pull? Sure. Because it is fucking inefficient to go around your knees and because it fucking hurts to slam the bar into your knees. But, there have been some good lifters who go around their knees. True story. Just like there are good lifters who start with their shoulders even with the bar and good lifters who cut their second pull short and good lifters who do all sorts of fucked up shit and still make the lift just because they are strong as all hell.

Finally, if you are going to quote the Level 1 text, then where on earth are you getting the idea that the bar slows or even stops accelerating before the second pull? No. It doesn't. If it does, then you are doing it wrong. Fast-faster-fastest. That's the tempo.

[Steve Hill]

Here is the thing. Unless I have badly mis-read the article, you and Rip are saying that the early shrug is to make the lever of the back longer... longer so as to more effeciently accellerate the bar from the knees up. In talking directly to Dimas (through another Greek who spoke better english) and to his old coach iovonko (sp?) both of them believe that although no one taught him to do this, the advantage that it gives is to get the bar higher and further back towards him and thus make his second pull or explosive phase (which starts at the hip) stronger and more explosive.

I'm going to summarize: You are stating that belief trumps scientific analysis if the person who believes is an "expert."

Herein lies the problem with every single athletic federation that I've ever been involved with.

Beliefs are OK. Dimas and Ivanko can believe whatever works for them. I've got no problem with that. I'm just explaining, from a scientific perspective, why and how something works.

That being said, your statement that I insist "that the "acceleration" or second pull, or jump, or whatever you call it, starts at or near the knees, or anywhere much lower than the hip is crazy," is flatly erroneous. I did state that "(t)his is especially important at the point the weight clears the knees and the athlete “jumps.” The knee bend is an artifice of jumping - you cannot jump without the knee bend. It therefore follows that the statement is perfectly correct - the bar accelerates AFTER it clears the knees. You are constructing, perhaps unwittingly, a straw-man argument and then knocking it down.

But this is par for the course on teh intarwebs.

[Beau Bryant]

Thanks for the article Rip and Steve. How about this, can someone please explain to me the reasoning to start the bar in front of mid foot with the hips low? Then if you could back that explanation up with sound physics I would appreciate it. Thanks

I tried to get this explanation at my Club Cert but got everything but an actual answer.

[Bazarov]

Thanks for posting a thought provoking article guys. Along the same lines, Bob Hoffman wrote quite a few articles in the 50s in which he argues against the S curve. (Which, given Bill Starr's connection to Hoffman, and Rip's connection to Starr, that makes sense). On the other hand, Tommy Kono has argued for years in favor of an S curve. Generally, I've found Kono's line of reasoning more convincing.

The argument against an S curve seems to come down to two points: balance around the center of mass and wasted energy. I think it's worth noting that proponents of an S curve aren't pushing some dramatic sweep of the bar. It seems to me that the area (not point) of the mid foot over which the bar must stay for everything to remain in balance is large enough to accommodate the very flat S curve these guys have in mind -- it's quite obvious when this S curve becomes too dramatic that things go wrong (I don't think anyone would argue otherwise). Furthermore, I'm not sure the area of balance remains static: it's often been noted that during the first pull, balance is shifted from the balls of the feet to the heels, followed by a shift back on to the toes after the second pull. So an S curve doesn't necessarily imply things are going to get out of balance -- perhaps it keeps things in balance.

Further along that vein, I would also note that if a lifter is going to "move the body around the bar" (which is definitely what he should be doing, I think) he will do so by moving the knees back out of the way of the bar as it comes off the ground. It seems to me that if the knees are moving back so must the hips, and if the back angle is maintained (or even partially maintained) with the shoulders over the bar, the bar, too, must move back as it comes off the ground. That is, the initial inward movement of the S curve is, in fact, an attempt to keep the bar close the body (i.e., directly over the center of gravity) as the lifter moves his knees back out of the way of the bar. That makes sense to me, anyways -- if I'm way off here, please correct me.

If horizontal movement off the floor doesn't move the bar outside the center of gravity, the argument against such movement comes down to wasted energy: any energy spent on horizontal movement can't contribute to vertical movement, the main objective of weightlifting. Two things: moving the bar horizontally, so long as that movement doesn't throw the whole system out of balance (which is, obviously, absolutely key), shouldn't require much energy: the bar isn't being moved against gravity. Furthermore, we can't consider the mechanical efficiency of a vertical path in a vacuum: the human body is stronger in certain positions, and thus better suited to imparting vertical force from certain positions, and that simply might not accommodate a vertical bar path (to a greater or lesser degree, given individual anthropometry). That would mean human beings (prepare to be shocked) aren't designed to move loaded barbells from the floor to overhead in the most mechanically efficient manner (i.e., a straight line ). Thus the human body might have to waste some energy by moving the bar horizontally in order to get the bar, and the body in relation to the bar, to a position from which it can apply the most vertical force. Such movement might not be 100% mechanically efficient, but it might be the most efficient way for a human body to move a loaded barbell (the two aren’t necessarily the same).

[mlentzner]

Been thinking about this.

Wouldn't it be more correct to say that the centroid of the lifter/barbell system is what needs to be moving perpendicular to the ground? The lifter isn't just moving the barbell, they also has to move their own mass which is a non-trivial component in the whole system.

Since the barbell is moving in relation to the lifter throughout the movement it would suggest that the barbell wouldn't necessarily move in a straight line since it has to adjust for being in a changing relationship to the lifter's COM such that the lifter/barbell system as a whole maintains it's perpendicular acceleration.

I would concede that as the barbell gets heavier it follows that the ideal bar path will become straighter since more mass is distributed in the barbell there and it's motion is more dominant.

[Mark Rippetoe]

I tried to get this explanation at my Club Cert but got everything but an actual answer.

But thebigdog says this is NOT the dogma.

Thanks for posting a thought provoking article guys. Along the same lines, Bob Hoffman wrote quite a few articles in the 50s in which he argues against the S curve. (Which, given Bill Starr's connection to Hoffman, and Rip's connection to Starr, that makes sense). On the other hand, Tommy Kono has argued for years in favor of an S curve.

Bill has never spoken to me about the bar path off the floor, ever.

The argument against an S curve seems to come down to two points: balance around the center of mass and wasted energy. I think it's worth noting that proponents of an S curve aren't pushing some dramatic sweep of the bar. It seems to me that the area (not point) of the mid foot over which the bar must stay for everything to remain in balance is large enough to accommodate the very flat S curve these guys have in mind -- it's quite obvious when this S curve becomes too dramatic that things go wrong (I don't think anyone would argue otherwise). Furthermore, I'm not sure the area of balance remains static: it's often been noted that during the first pull, balance is shifted from the balls of the feet to the heels, followed by a shift back on to the toes after the second pull. So an S curve doesn't necessarily imply things are going to get out of balance -- perhaps it keeps things in balance.

Further along that vein, I would also note that if a lifter is going to "move the body around the bar" (which is definitely what he should be doing, I think) he will do so by moving the knees back out of the way of the bar as it comes off the ground. It seems to me that if the knees are moving back so must the hips, and if the back angle is maintained (or even partially maintained) with the shoulders over the bar, the bar, too, must move back as it comes off the ground. That is, the initial inward movement of the S curve is, in fact, an attempt to keep the bar close the body (i.e., directly over the center of gravity) as the lifter moves his knees back out of the way of the bar. That makes sense to me, anyways -- if I'm way off here, please correct me.

If horizontal movement off the floor doesn't move the bar outside the center of gravity, the argument against such movement comes down to wasted energy: any energy spent on horizontal movement can't contribute to vertical movement, the main objective of weightlifting. Two things: moving the bar horizontally, so long as that movement doesn't throw the whole system out of balance (which is, obviously, absolutely key), shouldn't require much energy: the bar isn't being moved against gravity. Furthermore, we can't consider the mechanical efficiency of a vertical path in a vacuum: the human body is stronger in certain positions, and thus better suited to imparting vertical force from certain positions, and that simply might not accommodate a vertical bar path (to a greater or lesser degree, given individual anthropometry). That would mean human beings (prepare to be shocked) aren't designed to move loaded barbells from the floor to overhead in the most mechanically efficient manner (i.e., a straight line ). Thus the human body might have to waste some energy by moving the bar horizontally in order to get the bar, and the body in relation to the bar, to a position from which it can apply the most vertical force. Such movement might not be 100% mechanically efficient, but it might be the most efficient way for a human body to move a loaded barbell (the two aren’t necessarily the same).

So, here is your opportunity to make your argument FOR a curved bar path, instead of just saying that it MAY be better, or that some very good lifters do it. Tell us how, specifically, a horizontal component to the bar path improves the vertical efficiency of the pull. We can coach a vertical bar path quite easily, and we have been doing so for a long time. Why should we NOT do so, specifically please?

[Steve Hill]

But thebigdog says this is NOT the dogma.

I think that thebigdog thinks that we think that USAW is the keeper of the dogma, when in fact, they are vastly outnumbered by the crossfitters.

[Steve Hill]

Wouldn't it be more correct to say that the centroid of the lifter/barbell system is what needs to be moving perpendicular to the ground? The lifter isn't just moving the barbell, they also has to move their own mass which is a non-trivial component in the whole system.

It would if they were rigidly coupled, but they are not. The only exception to this is the clean, when the weight and the lifter ARE rigidly coupled when the weight is on the deltoids. And with large weights bouncing around, even then....

This is evident if you watch a snatch that is caught poorly.

Since the barbell is moving in relation to the lifter throughout the movement it would suggest that the barbell wouldn't necessarily move in a straight line since it has to adjust for being in a changing relationship to the lifter's COM such that the lifter/barbell system as a whole maintains it's perpendicular acceleration.

I would concede that as the barbell gets heavier it follows that the ideal bar path will become straighter since more mass is distributed in the barbell there and it's motion is more dominant.

The other point that you need to remember is that we already do this automatically - we keep our centroid over our "balance point" without conscious thought. That includes when we have heavy stuff in our hands. Since our body is not rigidly coupled to the bar, we can play around with this a bit, but that induces an opposing horizontal motion in the bar. Which we contend is not optimal.

[mlentzner]

It would if they were rigidly coupled, but they are not. The only exception to this is the clean, when the weight and the lifter ARE rigidly coupled when the weight is on the deltoids. And with large weights bouncing around, even then....

Hm. I would think that they *are* rigidly coupled during the first and second pull. Of course, once the bar begins decelerating during the third pull there is a detachment and then the two objects are moving independently.

If you had a crane hoisting a weight the balance point of the system would be the combined COM of the crane and the weight. As long as force is being transmitted through the cable then it is 'rigid'. (Of course we are ignoring any deformation of the components).

Another example would be thrown bolas (two weights attached by a rope). That system rotates around the COM even though the attachment is flexible (but effectively rigid when enough force is applied).