Can gripping too low decrease pole rotation??

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Can gripping too low decrease pole rotation??

Unread postby KYLE ELLIS » Sat Dec 12, 2009 9:52 pm

Can gripping below ones optimal grip for their spped and technique decrease pole speed? My feelings are yes, I am still juggling everything in my mind; I can see it in my own mind but it is difficult too explain.
For example Joe Schmoe normally grips 14'0 on a 14'6 190, Joe keeps brushing the bar on the way down and decides to drop his grip down to 13'10. Lets just say for arguement sake that he is fast enough and good enough to grip 14'2; what will happen when he drops his grip down two inches??
How do you know if your athlete is gripping too low??

My guess the top arm should reach a 90 degree angle as the hips are rising to be level or slightly above the head, if the pole unbends to early and the top arm is pulled past 90 degrees before the hips are even with the head this not only affects the inversion but also penetration.
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Re: Can gripping too low decrease pole rotation??

Unread postby KirkB » Sun Dec 13, 2009 1:46 am

I wouldn't think about the angle of the top arm. Instead, I would think about it in pure physics terms ...

Let's assume ... as you say ... that Joe's 14-0 grip rotates the pole to vertical. It does this becuz the bend in the pole gives an effective stiff-pole chord of x. We know that if he grips 14-2, he will bend the pole more than x, and a 13-10 grip will bend the pole less than x ... proportionally more and proportionally less than at 14-0 ... but not the full 2" ... but a certain % of x.

You question ... if I understand it correctly ... is whether the 13-10 grip might result in a chord that's MORE than the chord of the 14-0 grip ... which would make the pole rotate LESS. I think that's the only question ... nothing to do with arm angles.

The answer is that the chord of the pole will always be proportional to the grip ... but in the SAME DIRECTION ... so a lower grip will ALWAYS result in more pole rotation (given the same runway speed and takeoff oomph). I should clarify this a bit here and say that on a given pole, the % of the chord decreases proportionally as the grip is lowered ... and increases porportionally as the grip is raised.

The only exception that I can think of is if the lower grip is lower than the grip range recommended by the mfr. In that case, the shape of the sail piece might affect the bend in a non-proportional way.

I'm just using common sense here ... and a basic knowledge of physics ... so I stand corrected if there's something that I didn't realize. Keep in mind that I'm ignoring the angle of the top arm, becuz I'm assuming (correctly, I believe) that the chord length is predetermined once you leave the ground ... provided that you're not blocking with the bottom arm ... in which case all bets are off. Since you only referred to the top arm, I think my physics applies.

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Re: Can gripping too low decrease pole rotation??

Unread postby KYLE ELLIS » Sun Dec 13, 2009 2:55 am

Ok forget the whole arm angle thing as that pretains more to the inversion rather than pole rotation.

Pole vaulters are able to grip much higher on bending poles than non bending poles because the poles compress thus shortening the chord. So if your grip below your potential the pole will not compress as much and the chord will be greater. It seems as though on Bubkas best jumps & takeoffs the pole bends a little past 90 degrees, and he has no noticible passive phases. So what I am getting at is that if the pole doesn't reach a 90 degree bend the vaulter is not optimizing their grip and there will be problems with the inversion.... Also on the same hand if the pole bends past 90 degress then the vaulter will experience passive phases decreasing vertical velocity. I think I am answering my own question here, thanks for the inspiration.

What I mean by 90 degrees is that the handle of the pole is parallel to the runway. Blocking out will cause the pole to reach maximum bend early in the vault. Pulling down will unbend the pole early which is also bad for pole rotation. Taking off under will decrease the pole bend and taking off too far out will cause overbending.
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Re: Can gripping too low decrease pole rotation??

Unread postby KirkB » Sun Dec 13, 2009 4:53 am

KYLE ELLIS wrote: ... if the pole doesn't reach a 90 degree bend the vaulter is not optimizing their grip and there will be problems with the inversion.... Also on the same hand if the pole bends past 90 degress then the vaulter will experience passive phases decreasing vertical velocity. ...

I think you're on the right track here, but I think the passivity occurs at an angle less than 90 degrees ... which we call "crushing the pole". I know this, becuz that was a fault of mine in my career. It relates to "waiting for the pole to return" (passive), rather than maintaining a constant and continuous UPWARDS motion. Too much forwards, not enough upwards. Penetration is good, but too much penetration is passive ... bad. This occurs at something less than 90 degrees ... IMHO.

Re your mention of "problems with the inversion", I think the problem is not whether you hit 90 degrees or not (or whatever the optimal angle < 90 degrees is) ... but rather, whether you stay with the pole. If you get too far behind the pole (timewise), then you're going to have to muscle up (causing leakage). If you get too far ahead of the pole (timewise), then you're introducing passivity ... while you wait for the pole to catch up.

KYLE ELLIS wrote: ... Taking off under will decrease the pole bend ...

Actually, if you're under, then you're prying the pole into an early bend whilst your foot is still firmly planted on the ground. This causes leakage (energy loss) back into the ground thru this passive takeoff foot (that isn't moving while it's planted ... in the extreme case). So this won't DECREASE pole bend ... it will INCREASE it ... at the expense of drastically killing your swing (non-Petrovers can quite rightly argue this point).

KYLE ELLIS wrote: ... and taking off too far out will cause overbending.

No, that doesn't sound right. It will cause gravity to grab you and pull you down ... while you're in midair (between when you jump and when the pole hits) ... but that doesn't directly cause overbending. It will be a less efficient jump, but if you're on a pole that fits that technique, then it won't overbend.

My personal preference is to be a little out rather than a little in. There's 2 reasons for this.

First, you can't hit your optimal takeoff perfectly every time, so I'd rather err on the side of being a little out, which will prevent the leakage thru the firmly planted foot that I mentioned earlier.

Second, it takes more than a microsecond for the foot to leave the ground and your body weight to be tight on the pole. That's due to the fact that no matter how tight you try to make your body when the pole hits, it's never perfectly tight. So there's a certain number of microseconds (> 1 ... but I don't know exactly how many) where the system is in limbo ... as the body absorbs the shock of the pole hitting. For this reason, even a perfectly timed free takeoff isn't perfect.

Maybe what I'm trying to say is that even if your step is exactly "on", it will feel like you're out a bit ... due to the time it takes for your body to tighten the slack. By the same logic, I suppose that some vaulters might think they're "on" when in fact they're slightly under ... becuz their body becomes tight to the pole exactly when it hits. So I suppose you could argue that one both ways ... but due to the first issue I mentioned, my preference is still to be a bit out.

It's getting late ... perhaps I'm not making much sense. It might be clearer to me in the morning.

Kirk
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Re: Can gripping too low decrease pole rotation??

Unread postby KYLE ELLIS » Sun Dec 13, 2009 1:16 pm

I think you're on the right track here, but I think the passivity occurs at an angle less than 90 degrees ... which we call "crushing the pole". I know this, becuz that was a fault of mine in my career. It relates to "waiting for the pole to return" (passive), rather than maintaining a constant and continuous UPWARDS motion. Too much forwards, not enough upwards. Penetration is good, but too much penetration is passive ... bad. This occurs at something less than 90 degrees ... IMHO.


I completely agree, your less than 90 is what i was calling greater than 90. Why do you say less than 90?? If the degree of bend is increasing as the pole is bending more then wouldn't overbending the pole be bending the pole more than 90 degrees??

Re your mention of "problems with the inversion", I think the problem is not whether you hit 90 degrees or not (or whatever the optimal angle < 90 degrees is) ... but rather, whether you stay with the pole. If you get too far behind the pole (timewise), then you're going to have to muscle up (causing leakage). If you get too far ahead of the pole (timewise), then you're introducing passivity ... while you wait for the pole to catch up.


This is exactly what I was talking about, the timing of you with the pole. If the pole unbends early then you will be behind, and if it overbends you will be ahead (passive).

Actually, if you're under, then you're prying the pole into an early bend whilst your foot is still firmly planted on the ground. This causes leakage (energy loss) back into the ground thru this passive takeoff foot (that isn't moving while it's planted ... in the extreme case). So this won't DECREASE pole bend ... it will INCREASE it ... at the expense of drastically killing your swing (non-Petrovers can quite rightly argue this point).


Kirk you just said it yourself you will lose energy at takeoff, so how do you bend the pole more when you put less energy into it???????????

No, that doesn't sound right. It will cause gravity to grab you and pull you down ... while you're in midair (between when you jump and when the pole hits) ... but that doesn't directly cause overbending. It will be a less efficient jump, but if you're on a pole that fits that technique, then it won't overbend.


Lol, how does it not sound right? You just explained it. If you takeoff out you will sink and that sink comes from the pole bending alot!! The only way to adjust is to grip lower to stiffen up the pole, in that case you are decreasing your optimal grip. This is why you should see the pole just hitting the box as you move onto the tip of your toe.

My personal preference is to be a little out rather than a little in. There's 2 reasons for this.

First, you can't hit your optimal takeoff perfectly every time, so I'd rather err on the side of being a little out, which will prevent the leakage thru the firmly planted foot that I mentioned earlier.

Second, it takes more than a microsecond for the foot to leave the ground and your body weight to be tight on the pole. That's due to the fact that no matter how tight you try to make your body when the pole hits, it's never perfectly tight. So there's a certain number of microseconds (> 1 ... but I don't know exactly how many) where the system is in limbo ... as the body absorbs the shock of the pole hitting. For this reason, even a perfectly timed free takeoff isn't perfect.

Maybe what I'm trying to say is that even if your step is exactly "on", it will feel like you're out a bit ... due to the time it takes for your body to tighten the slack. By the same logic, I suppose that some vaulters might think they're "on" when in fact they're slightly under ... becuz their body becomes tight to the pole exactly when it hits. So I suppose you could argue that one both ways ... but due to the first issue I mentioned, my preference is still to be a bit out.

It's getting late ... perhaps I'm not making much sense. It might be clearer to me in the morning.

Kirk


Kirk why do you want your body to be tight?? I don't understand this. If you tighten your body at takeoff you will lose pole penetration.
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Re: Can gripping too low decrease pole rotation??

Unread postby KirkB » Sun Dec 13, 2009 4:24 pm

It's a little clearer to me this morning ... sorry for my vagueness or misunderstandings.
KYLE ELLIS wrote: ... your less than 90 is what i was calling greater than 90. Why do you say less than 90?? If the degree of bend is increasing as the pole is bending more then wouldn't overbending the pole be bending the pole more than 90 degrees??

I mean that the optimal bend is at (maybe) 80 degrees. I don't know the exact angle, but it's less than 90. So between 80-90, you're crushing the pole. This doesn't mean that the pole's characteristics change in this range, and you literally CRUSH the pole. Rather, it means that some of the time spent in bending it that last 10 degrees (or so) is better spent in moving your body UPWARDS ... before gravity pulls you back down too much (as it will at > ~80 degrees).

KYLE ELLIS wrote:
KirkB wrote: Actually, if you're under, then you're prying the pole into an early bend whilst your foot is still firmly planted on the ground. This causes leakage (energy loss) back into the ground thru this passive takeoff foot (that isn't moving while it's planted ... in the extreme case). So this won't DECREASE pole bend ... it will INCREASE it ... at the expense of drastically killing your swing (non-Petrovers can quite rightly argue this point).

Kirk you just said it yourself you will lose energy at takeoff, so how do you bend the pole more when you put less energy into it???????????

You're putting more POTENTIAL energy into the pole when you're under and prying on it, but there's less energy (left over from your run) that's put into the swing. The net amount of energy still in the system is LESS because of the leakage. This is a very common misunderstanding ... the trap that tuck/shooters too often fall into.

KYLE ELLIS wrote:
KirkB wrote: No, that doesn't sound right. It will cause gravity to grab you and pull you down ... while you're in midair (between when you jump and when the pole hits) ... but that doesn't directly cause overbending. It will be a less efficient jump, but if you're on a pole that fits that technique, then it won't overbend.

Lol, how does it not sound right? You just explained it. If you takeoff out you will sink and that sink comes from the pole bending alot!! The only way to adjust is to grip lower to stiffen up the pole, in that case you are decreasing your optimal grip. This is why you should see the pole just hitting the box as you move onto the tip of your toe.

What I was missing in my explanation last night was that there's a passive takeoff, and then there's an active takeoff. For instance, Isaksson is 5-8 but HJs 6-4. You better believe that his takeoff was ACTIVE! He's JUMPING on takeoff! But if you're "out" and you DON'T jump, then all bets are off ... you might sink as you say. That's not the takeoff style that I was referring to ... since I was a leaper myself (but paled in comparison to Isaksson ... I barely HJ'd my height ... 6-0). You see, there's a GAP (time-wise and distance-wise) on a free takeoff ... between when you leave the ground and when the pole hits. A leaper will close this gap by JUMPING, whereas if you just let the pole pick you off the ground, then you won't be quickly closing that gap ... and like you say ... gravity will pull you down and you'll "sink".

KYLE ELLIS wrote: Kirk why do you want your body to be tight?? I don't understand this. If you tighten your body at takeoff you will lose pole penetration.

There's 2 kinds of "tight". I was not referring to the tightness that you get from your elastic prestretch. That occurs a little later than the tightness that I was referring to. Call it semi-tight if you like ... to distinguish from the other kind of tight ... but what I mean is the tightness that you need just BEFORE your elastic prestretch ... as you "fill the gap". After all, when you penetrate your chest forwards and your trail leg backwards, your body can't be like a bowl of mush. It needs to have SOME tightness.

Conclusion: I still think that you're not going to overbend the pole if you're "out" a bit. Rather, your takeoff is STRONG, so you'll need to get on a heavier pole ... becuz you're JUMPING off the ground efficiently! I'm only referring to a couple inches "out". If you're out by a lot (say a foot) when attempting a decent bar, then even the best HJer in the world won't be able to jump hard enough to sustain a good takeoff. But in that case, the jump will be so bad (not smooth) that you should bail.

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Re: Can gripping too low decrease pole rotation??

Unread postby KYLE ELLIS » Sun Dec 13, 2009 4:35 pm

If you are out 4 inches (just as an example), and you don't sink on the pole then you should raise your grip an inch and a half or 2 inches so that you are now on. If not you are sacrificing grip height. Its not an excuse of how good of a leaper you are, if you are a good leaper it doesn't mean you should takeoff out it means you should raise your grip which will cause you to takeoff further out.
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Re: Can gripping too low decrease pole rotation??

Unread postby KirkB » Sun Dec 13, 2009 4:47 pm

KYLE ELLIS wrote:If you are out 4 inches (just as an example), and you don't sink on the pole then you should raise your grip an inch and a half or 2 inches so that you are now on. If not you are sacrificing grip height. Its not an excuse of how good of a leaper you are, if you are a good leaper it doesn't mean you should takeoff out it means you should raise your grip which will cause you to takeoff further out.

Kyle, I see what you're saying, but we're still not on the same wave length.

I think you're forgetting that raising your grip by 1.5-2.0 inches will slow your pole speed.

Think of it this way ... your step is never exactly "on". It can only be CLOSE to being "on" ... plus or minus a couple inches. Personally, I never liked to be under (directly under the top hand). I also liked the feel of leaning forwards a bit (or at least not leaning backwards). So I aimed at being a couple inches out. Then, on any given jump, I was hardly ever under (if I was, I bailed), and I was occasionally out by as much as 4".

If I had simply raised my grip ... effectively moving my takeoff out by 1.5-2.0 inches ... then I'd be UNDER more often ... and I'd have trouble rotating the pole to vertical.

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Re: Can gripping too low decrease pole rotation??

Unread postby KirkB » Mon Dec 14, 2009 2:48 am

Kyle, your thoughts about whether or not you're "wasting" the 1.5-2.0" by not moving your takeoff back are valid ... in that you always need to question whether you can "afford" the higher grip. Pole speed is the main consideration.

But I don't think you should always optimize pole speed to the extent that you're getting every last bit of grip out of the pole ... to the point of just barely making it to vertical. The reason I say this is becuz you need some momentum in reserve that you can use to put more oomph into your extension. If you've used it all up with a higher grip, then you can't pull thru your extension as vigorously. I always felt that a 2" lower grip with a harder and faster extension gained you much more than 2" off the top. So the main objective isn't to maximize your grip ... it's to optimize the sum of your grip plus your pushoff.

The reason for this is that if you have loads of momentum during your extension ... with your standards at 80 ... you can pull as hard and as fast as you want, without ANY fear of stalling out. In fact, you HAVE TO pull upwards (even a little back towards the runway) much harder just to keep from blowing thru. This is worth much more than the 2" you give up in grip.

And you can GOVERN (make faster or slower) your extension based on how much pole rotation you have. That's an adjustment that you make in real-time ... whilst on the pole. In comparison, you can't govern your grip (make higher or lower) if you find ... when you take off ... that you're under or out a bit ... there's no real-time control over that!

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Re: Can gripping too low decrease pole rotation??

Unread postby kcvault » Mon Dec 14, 2009 3:16 am

Often a two inch higher grip makes the pole softer and therefor roll easier. As a result although you are gripping higher you will not get as big of a push off. Each pole has it's own optimal grip relative to you height and weight (and other variables such as take off and speed). From my own personal experience I know the first time I jumped 17ft I went from 16'6 to 17ft with ease by just raising my grip 2 fingers. Thinking I was on to something I raised my grip another 4 fingers and and blew through and crushed the pole so much I would not have made the 16'6 bar. I have also had experience where I jumped much higher on a smaller pole because I lowered my grip a couple fingers.

Now When I practice I will continue to raise my grip on the smaller pole until my push off starts to suffer. once this happens I will either lower my grip to where my optimal push off was and jump on that pole for the rest of practice. Or if able to I will go to the next pole and raise my grip one finger.Not sure how others determine optimal grip height but this is how I think of it.

I think Bob Slover did a lot of work were he would calculate the weight of the pole compared to the weight of the vaulter as will as height and be able to figure out where the optimal grip height is. (might have been someone else who did this but I think it was bob slover) Of course my experience is with more of a drive style vault but I do not think this would be different for a petrov style jump.

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Re: Can gripping too low decrease pole rotation??

Unread postby Robert schmitt » Mon Dec 14, 2009 3:03 pm

KYLE ELLIS wrote:What I mean by 90 degrees is that the handle of the pole is parallel to the runway. Blocking out will cause the pole to reach maximum bend early in the vault. Pulling down will unbend the pole early which is also bad for pole rotation. Taking off under will decrease the pole bend and taking off too far out will cause overbending.



I understand what you are saying and it is a common que or point to look at the handle of the pole parallel to the run way as a que for a 90 pole bend but it's greater than 90 dgrees at this point because the back of the box is not plum vertixcal it is at and angle so while the handle is parallel with the runway the butt end of the pole is past vertical. You may already realize this but I just wanted to bring this point up.
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Re: Can gripping too low decrease pole rotation??

Unread postby KirkB » Mon Dec 14, 2009 3:50 pm

Robert schmitt wrote: ... it is a common que or point to look at the handle of the pole parallel to the run way as a que for a 90 pole bend but it's greater than 90 degrees at this point because the back of the box is not plum vertical it is at and angle so while the handle is parallel with the runway the butt end of the pole is past vertical. ...

The pole doesn't actually use the extra angle of the backstop (15 degrees from the bottom plane of the box) in strict side view. It only uses it towards the top CORNER of the box. This is becuz it's not at anywhere near full bend in strict side view.

Also realize that the old 90 degrees was measured from the bottom plane of the box too - not the horizontal plane. That old 90 degree angle became 105 degrees on the new boxes ... both measured from the bottom plane.

Remember that the max bend is approaching sideways to the box (not strict side view, but not strict front view either) ... it's not straight-forward to the box, so you can't take a strict side-view and compute the angle. As the pole is bending, it's heading for the top-left corner of the box for a right-handed vaulter. Max bend is reached prior to the pole rotating to vertical. What angle is the chord at then? I don't know ... but if the planted pole starts at a 30 degree angle (sounds about right) ... and then bends ... and then unbends to be exactly vertical on pushoff ... then I would guess that max bend is at about 60 degrees (in strict side-view) - half way between the plant and pushoff. At this point, the pole is approaching the top CORNER of the box.

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