technical model

[Lax PV]

powerplant42 wrote:
It just shows you how badly American is plagued by the tuck and shoot... Is a 6.4 meter jump not enough to knock some level of sense into elite vault coaches? I think some people REALLY need to get out more.


when did someone jumped 6.4 meters? am i missing something

Please don't make it like it didn't happen... it was a 6.4 jump over a much lower bar, and you know it.

All I'm saying is that the Petrov model, when learned as well as Bubka did, will ALWAYS be dominant over an equally sized opponent that has mastered the tuck and shoot...

In all honesty... I kind of side with VTech here. While I agree that Petrov is right, Brian is right...

It doesn't matter how high you clear a bar, the fact is, it was at something (at best) 25cm lower. And that is to take nothing away from great jumps, it's just a part of competition.

Alas the convo has digressed. I tuck. I was taught to tuck when I was in high school, and for the most part, I still probably do out of habit. As the axis of rotation shortens, it will speed up rotation (conservation of momentum off all kinds...). HOWEVER, people forget that a human body doesn't like to exert more force than it has to. If you are going to pick up 5 pounds (and you know it's 5 pounds) you are not going to lift it like it were 50. That said, a shorter radius causes a smaller amount of torque on the shoulders, thus, the vaulter will not exert as much force on the pole. I think this is where the model falls, because it lowers the energy that can be added by a good, long swing.

Just my two cents on the swing.

[VTechVaulter]

look im not saying that swinging long to cover pole isn't the best way to pole vault. and im not saying we should try to tuck and shoot.

ill use myself as an example. when im jumping well i do swing long for most of the jump. however there are times when i inadvertantly tuck and shoot to save other jumps.

i don't think most people tuck and shoot intentionally. If you have every seen Jeff Hartwig jump from short run, he swings very well through the entire jump. Still just hasn't gotten from a long run.

its not all that easy to do, especially as you are taller. that is what made tarasov so amazing.

how many taller vaulters swing the entire way to cover the pole. Brad doesn't, jeff doesn't, brits didn't, galfione didn't.

and p.s. if we are gonna give people credit for hip height, brad walker jumped about 6.20 last week.

[achtungpv]

its not all that easy to do, especially as you are taller. that is what made tarasov so amazing.

I've been thinking about that a lot the past year or so. Everybody's has always thought that taller vaulters have an advantage because of the higher takeoff angle and ability to grip higher. That's true but those advantages don't seem to overcome the common technical flaws the 6'4"+ vaulters all have...break at the hips to speed the rotation and then tuck. Is there a point where the pendulum is too long? I don't know. Maybe a physics guru can chime in but there seems to be a reason why tall vaulters, even those that grow up with the Petrov Model (i.e. Chistyakov 6'7"), can't quite fully realize the technical model. But other than Tarasov (who wasn't quite perfect) few of the 6'4"+ guys has come remotely close to "jumping the model" (Actually, I can only think of Trandenkov as an example). I think to jump the model the sweet spot for height is probably 5'11" to 6'2".

[dj]

good morning

i actually didn't consider Tully a tuck vaulter.. and know he never intended to "tuck" but i do know he would "shorten the radius" to invert faster if the pole speed dictated it.. or move his grip a little closer..

maybe wide grips and/or trying to spend more time on the "down" phase or as i mentioned before the pole design or even size could play a role in what the vaulter does to "match up"..

dj

[KirkB]

its not all that easy to do, especially as you are taller. that is what made tarasov so amazing.

... Everybody's has always thought that taller vaulters have an advantage because of the higher takeoff angle and ability to grip higher. That's true but those advantages don't seem to overcome the common technical flaws the 6'4"+ vaulters all have...break at the hips to speed the rotation and then tuck. Is there a point where the pendulum is too long? I don't know. Maybe a physics guru can chime in but there seems to be a reason why tall vaulters, even those that grow up with the Petrov Model (i.e. Chistyakov 6'7"), can't quite fully realize the technical model. ... I think to jump the model the sweet spot for height is probably 5'11" to 6'2".

I like this theory (especially the part about "Is there a point where the pendulum is too long?"), becuz I've watched a lot of elite male gymnasts perform ring and high bar moves in competition.

I've also watched a lot of competitive trampoline; double-mini; and tumbling, and some competitive diving. For example, the taller you are, the harder it is to do a triple-somersault on the tramp. This is easily explained by the laws of physics. No matter how well tucked they are when they rotate, taller athletes stick out further from their CoG (aka CoM). Thus, each flip takes longer. To scale the entire trick, a taller athlete would have to jump proportionally higher prior to the trick (assuming he does the triple on his first trick). Tough to do. World class trampolinists do several triples in their 10-trick routine - one after the other. Not easy for the tall guys.

As a side-point, some trampolinists (and divers) "cowboy" their somersault to rotate faster. They lose technical points for this, because you're supposed to keep your knees together. I've seen lots of vids of elite vaulters that cowboy it - no penalty points there, as long as they clear the bar! Quiz: Can you name them?

Why are all gymnasts short? I think becuz there's a certain strength/weight/height ratio that defines an elite gymnast. I'm sure studies have been done on this, but I don't know of any offhand.

Just to confuse things a bit, you might have also noticed that high bar specialists are (on average) slightly taller and more slender than rings (or other event) specialists. I attribute that to the swinging motions on high bar (same as in pole vaulting) not needing as much strength. The purer strength-to-weight ratios needed in the other events require shorter gymnasts. That's good news for tall pole vaulters.

If anyone agrees with that gymnastics logic, can we take it and apply it to the PV?

Kirk

[VTechVaulter]

since we like to throw the word "physics" around id like to put something out and then ill relate it to proven equations

lets say your standing on a platform that can rotate. for now we will assume to friction for the sake of argument. now hold your arms out as far as they will reach and have someone spin you. as your spinngin pull your arms in, your rotation speeds up, as you let them spread out again, you will return to your original angular velocity.

so my belief is that as long as you begin the swing with a good long whipping actuion through the cord of the pole, curling your legs in a bit to keep your hips moving upward is not the worst thing you can do. from a "physics" standpoint, there is no energy loss.

classic examples of this include
Toby Stevenson
Guisseppe Gibilisco


the equations that govern this whole principle are based on the law of conservation of angular momentum, stating that in a closed system, the sum of all torque equals 0.

[dj]

good morning

good post vtech. i think the point that should be well taken is that it is the "action" that determines the out come.. much like the impluse at the takeoff.. not the frame by frame without considering the speed of movement.

dj

[decanuck]

Is there a point where the pendulum is too long? I don't know. Maybe a physics guru can chime in but there seems to be a reason why tall vaulters, even those that grow up with the Petrov Model (i.e. Chistyakov 6'7"), can't quite fully realize the technical model. But other than Tarasov (who wasn't quite perfect) few of the 6'4"+ guys has come remotely close to "jumping the model" (Actually, I can only think of Trandenkov as an example). I think to jump the model the sweet spot for height is probably 5'11" to 6'2".

Excellent food for thought. Recall Alan's distinction between technical model and style--model being the vision of perfection to which we aspire, style being the way in which we fall short of realizing that model due to our own individual physical characteristics. From a strict theoretical perspective, no one has realized the Petrov model--not even Bubka (though he was the closest). From a more pragmatic perspective, even tall vaulters can realize the model if their failings are attributable to style (i.e. physical limitations).

so my belief is that as long as you begin the swing with a good long whipping actuion through the cord of the pole, curling your legs in a bit to keep your hips moving upward is not the worst thing you can do. from a "physics" standpoint, there is no energy loss.

Indeed, your analysis is spot-on. There is no direct cost to tucking during inversion to speed rotation, but there is an opportunity cost. Let me explain...

Imagine you are doing a typical PV rope swing drill (swing, invert, extend up the rope) on a very flexible piece of bungee cord (you can actually watch this in the "Additional Drills" section of either the BTB or BTB2 DVD). Think about how your body position changes during this drill. When you start, your legs and centre of mass are underneath your hands. When you finish, they're above. This swing-invert-extend action has raised your centre of mass, and for every action there is an equal and opposite reaction. In this case, the reaction force is exerted on the rope. As you pull your centre of mass up, an equal force pulls down on the rope. You will notice that the bungee flexes according to this force and then recoils tight once the movement is complete.

A flexible pole works in the same fashion. The downward force of lifting your CoM in the inversion, extension, and pull/push phases has two effects: it increases the bend in the pole (storing more energy in it), and delays its unbending (giving you time to "cover" it, so that you can exploit the full force of it's recoil).

Remember that the swing has two sources of energy: the natural swing about the top hand (caused by your hands meeting resistance from the pole while your body's impulse carries you forward), and the kick-whip action of the pre-stretched muscles from the shoulders to the knee of the takeoff leg (i.e. the gymnastic tap swing effect). Once both these movements are complete, when you have kick-whipped your body into a straight position, like VTech said it doesn't matter what shape you take--the law of conservation of angular momentum will keep the energy from the swing the same. This is why even the tightest tuckers of the tuck-and-shoot vaulters will NEVER begin to tuck before they have swung straight.

The opportunity cost of tucking is that it cheats you out of energy you could be adding to the vaulter-pole system in the inversion and extension phases as you lift your centre of mass above your hands. Think back to the analogy of the swing-invert-extend drill on the bungee cord. Invert with a tight tuck, and the bungee stretches a little. Now invert with as straight a body as your strength allows, and the bungee stretches a LOT. Why? Because your bodyweight is cantilevered. Think of holding a pole straight up vs. straight out. The leverage weight of inverting a straight body is greater than that of a tucked body, so the resulting force on the bungee (pole) is greater, meaning more stretch (bend) and a harder recoil.

So then the challenge becomes, how do we perform all the prior parts of the vault in a way that both maximizes the energy of each earlier phase AND put ourselves in a position not to NEED a tuck, so that we can add more energy to the jump by inverting and extending with a straight(er) body?

[volteur]

Indeed, your analysis is spot-on. There is no direct cost to tucking during inversion to speed rotation, but there is an opportunity cost. Let me explain...

Imagine you are doing a typical PV rope swing drill (swing, invert, extend up the rope) on a very flexible piece of bungee cord (you can actually watch this in the "Additional Drills" section of either the BTB or BTB2 DVD). Think about how your body position changes during this drill. When you start, your legs and centre of mass are underneath your hands. When you finish, they're above. This swing-invert-extend action has raised your centre of mass, and for every action there is an equal and opposite reaction. In this case, the reaction force is exerted on the rope. As you pull your centre of mass up, an equal force pulls down on the rope. You will notice that the bungee flexes according to this force and then recoils tight once the movement is complete.

A flexible pole works in the same fashion. The downward force of lifting your CoM in the inversion, extension, and pull/push phases has two effects: it increases the bend in the pole (storing more energy in it), and delays its unbending (giving you time to "cover" it, so that you can exploit the full force of it's recoil).

Remember that the swing has two sources of energy: the natural swing about the top hand (caused by your hands meeting resistance from the pole while your body's impulse carries you forward), and the kick-whip action of the pre-stretched muscles from the shoulders to the knee of the takeoff leg (i.e. the gymnastic tap swing effect). Once both these movements are complete, when you have kick-whipped your body into a straight position, like VTech said it doesn't matter what shape you take--the law of conservation of angular momentum will keep the energy from the swing the same. This is why even the tightest tuckers of the tuck-and-shoot vaulters will NEVER begin to tuck before they have swung straight.

The opportunity cost of tucking is that it cheats you out of energy you could be adding to the vaulter-pole system in the inversion and extension phases as you lift your centre of mass above your hands. Think back to the analogy of the swing-invert-extend drill on the bungee cord. Invert with a tight tuck, and the bungee stretches a little. Now invert with as straight a body as your strength allows, and the bungee stretches a LOT. Why? Because your bodyweight is cantilevered. Think of holding a pole straight up vs. straight out. The leverage weight of inverting a straight body is greater than that of a tucked body, so the resulting force on the bungee (pole) is greater, meaning more stretch (bend) and a harder recoil.

So then the challenge becomes, how do we perform all the prior parts of the vault in a way that both maximizes the energy of each earlier phase AND put ourselves in a position not to NEED a tuck, so that we can add more energy to the jump by inverting and extending with a straight(er) body?

Very nice! I like!

so continuing with the momentum of the discussion i have these thoughts now

-considering cantilevering as the process which transfers the force from body into pole

-considering whether torso stability control is what allows for a greater transfer of this force (the ability to resist bending)

-considering the point where the swing is ideally at it's longest, which is suggested to be when the longitudinal axis of the body meets the cord length of the pole

-considering whether it is a timing issue which determines the necessity to add tucking into the inversion or not (ie free-takeoff leads to a free inversion?)

volteur

[volteur]

I've also watched a lot of competitive trampoline; double-mini; and tumbling, and some competitive diving. For example, the taller you are, the harder it is to do a triple-somersault on the tramp. This is easily explained by the laws of physics. No matter how well tucked they are when they rotate, taller athletes stick out further from their CoG (aka CoM). Thus, each flip takes longer. To scale the entire trick, a taller athlete would have to jump proportionally higher prior to the trick (assuming he does the triple on his first trick). Tough to do. World class trampolinists do several triples in their 10-trick routine - one after the other. Not easy for the tall guys.

As a side-point, some trampolinists (and divers) "cowboy" their somersault to rotate faster. They lose technical points for this, because you're supposed to keep your knees together. I've seen lots of vids of elite vaulters that cowboy it - no penalty points there, as long as they clear the bar! Quiz: Can you name them?

Why are all gymnasts short? I think becuz there's a certain strength/weight/height ratio that defines an elite gymnast. I'm sure studies have been done on this, but I don't know of any offhand.

Just to confuse things a bit, you might have also noticed that high bar specialists are (on average) slightly taller and more slender than rings (or other event) specialists. I attribute that to the swinging motions on high bar (same as in pole vaulting) not needing as much strength. The purer strength-to-weight ratios needed in the other events require shorter gymnasts. That's good news for tall pole vaulters.

If anyone agrees with that gymnastics logic, can we take it and apply it to the PV?

Kirk

Some interesting bits like the 'cowboying' idea. Is this where the knees are spread to shorten the rotation axis?

Also the taller high bar gymnasts. Possibly this is also due to the fact that a powerful swing is very important aspect in the high bar.

But i do have to disagree on one point but only because i can make a point off it that i think is important. It is to do with taller athletes not being able to spin as quickly. Sure it's true when we observe most athletes but to be idealistic and to point out that it doesn't bother a planet or a sun how long it's radius is, a tall athlete can rotate as quickly as a shorter one, it just requires the ability to stay long and not lose stability.

the stability stuff with the posture is what i'm looking at here i guess

[Tim McMichael]

its not all that easy to do, especially as you are taller. that is what made tarasov so amazing.

... Everybody's has always thought that taller vaulters have an advantage because of the higher takeoff angle and ability to grip higher. That's true but those advantages don't seem to overcome the common technical flaws the 6'4"+ vaulters all have...break at the hips to speed the rotation and then tuck. Is there a point where the pendulum is too long? I don't know. Maybe a physics guru can chime in but there seems to be a reason why tall vaulters, even those that grow up with the Petrov Model (i.e. Chistyakov 6'7"), can't quite fully realize the technical model. ... I think to jump the model the sweet spot for height is probably 5'11" to 6'2".

I like this theory (especially the part about "Is there a point where the pendulum is too long?"), becuz I've watched a lot of elite male gymnasts perform ring and high bar moves in competition.

I've also watched a lot of competitive trampoline; double-mini; and tumbling, and some competitive diving. For example, the taller you are, the harder it is to do a triple-somersault on the tramp. This is easily explained by the laws of physics. No matter how well tucked they are when they rotate, taller athletes stick out further from their CoG (aka CoM). Thus, each flip takes longer. To scale the entire trick, a taller athlete would have to jump proportionally higher prior to the trick (assuming he does the triple on his first trick). Tough to do. World class trampolinists do several triples in their 10-trick routine - one after the other. Not easy for the tall guys.

As a side-point, some trampolinists (and divers) "cowboy" their somersault to rotate faster. They lose technical points for this, because you're supposed to keep your knees together. I've seen lots of vids of elite vaulters that cowboy it - no penalty points there, as long as they clear the bar! Quiz: Can you name them?

Why are all gymnasts short? I think becuz there's a certain strength/weight/height ratio that defines an elite gymnast. I'm sure studies have been done on this, but I don't know of any offhand.

Just to confuse things a bit, you might have also noticed that high bar specialists are (on average) slightly taller and more slender than rings (or other event) specialists. I attribute that to the swinging motions on high bar (same as in pole vaulting) not needing as much strength. The purer strength-to-weight ratios needed in the other events require shorter gymnasts. That's good news for tall pole vaulters.

If anyone agrees with that gymnastics logic, can we take it and apply it to the PV?

Kirk

I cowboyed as much as I possibly could. Dean Dial taught me to do this because he knew that I would probably have less time to rotate than practically anyone in the world. He taught moving the pole by staying down and behind it with a long trail leg swing, and at my size I could stay behind for a very long time, but this left me with only a split second to finish the swing, so I kept my legs and feet as wide as I could. It looked really funny from behind because my right leg splayed out away from me and then snapped back into line as the pole finished.

With a good enough takeoff, however, you don't have to do this. Joe Dial never did, and Dean never told him to, because he had a much faster run and was a lot stronger than me. His pole hitting the back of the box sounded like a shotgun and mine sounded like a popgun. LOL.

[KirkB]

... Remember that the swing has two sources of energy: the natural swing about the top hand (caused by your hands meeting resistance from the pole while your body's impulse carries you forward), and the kick-whip action of the pre-stretched muscles from the shoulders to the knee of the takeoff leg (i.e. the gymnastic tap swing effect). Once both these movements are complete, when you have kick-whipped your body into a straight position, like VTech said it doesn't matter what shape you take--the law of conservation of angular momentum will keep the energy from the swing the same. This is why even the tightest tuckers of the tuck-and-shoot vaulters will NEVER begin to tuck before they have swung straight.

The opportunity cost of tucking is that it cheats you out of energy you could be adding to the vaulter-pole system in the inversion and extension phases as you lift your centre of mass above your hands. ...

So then the challenge becomes, how do we perform all the prior parts of the vault in a way that both maximizes the energy of each earlier phase AND put ourselves in a position not to NEED a tuck, so that we can add more energy to the jump by inverting and extending with a straight(er) body?

Decanuck, you said a lot of good things in your last post, but I'll only comment on the parts that I've quoted above.

I agree with your analysis. We're all trying to do essentially the same thing - swing long, then invert as fast as possible. This sets us up for an efficient extension, just as you describe.

But I get the feeling that most of you couldn't "get ahead of the pole" quickly enough. Instead, you were always playing catchup with the pole, thus the row/tuck/cowboy stuff. I never had that problem.

I've described this in my Bryde Bend thread. See Post #3, which in part says:

... there’s TWO distinct parts of the vault where you can gain more altitude – first adding potential energy into the pole during the swing – as I just described – and second whilst the pole is recoiling!

... and Post #14 Single Leg Swing and Post #15 "Shoot (Extension)".

In part, I said:

My extension actually started as soon as I passed the chord of the pole. There was no rockback! After snapping “past the pole”, the sensation that I had was one of my shoulders sinking whilst my hips were raising and an increase in pressure ( a “pull” from the pole, felt thru both hands) on the pole.

I said it one way. You said it a better way. We're both saying the same thing.

Everyone discovers their own way to invert, and the path I took just happened to be a little different than anyone else. I lifted my trail leg back, which gave me the power to snap/whip/pop into an inverted position without the need to tuck. I'm not trying to convince anyone that my way's better, but I certainly found it the easiest way for me to invert without losing power. In fact, just as you said, I GAINED power by extending efficiently in unison with the pole.

I've been listening carefully to all the ideas everyone's brought forward on this thread, and really, you don't have to tuck if you lift your trail leg back and up, then snap/whip it around to an inverted position. You won't get as much power if you don't lift the leg first.

Then after the snap/whip/pop, you can pull like mad (starting by extending your hips and trunk, then finally with the arms), and you won't stall. It's the most exhilarating part of the vault!!! In fact, you have so much forwards momentum that you need to shoot backwards a bit to keep from hitting the bar on the way up. Before I did the Jump to the Split technique, I didn't have the runway speed and takeoff speed to rotate the pole into the pit, so I stalled all the time. Ouch!

Try it, you'll like it!

Kirk