What is your correct takeoff point?

[altius]

What you do not seem to have understood Kirk - and you would if you had really read BTB - is that the notion that a vaulter could accelerate into take off is not mine! It is that of Petrov and is supported -as I continually restate - by the data provided by Nikonov. On virtually all aspects of technique I turn first to Petrov and then to my attempts to translate his ideas into what works with my athletes. So if Roman believes what you are stating, he is not disagreeing with me but with the view of the other Russian coaches I refer to. As I recall this is the second time you have tried to point out differences between 'my' views and those of Roman -but by and large the same principle applies - 'my' views are essentially those of Petrov - so take up the discussion with him. But since I don't know how to pull up past posts then you will have to forgive me if I am mistaken - when you get old your memory starts to fade a bit -apparently frequent major surgery involving anaesthetics accelerates that process. It is perhaps also worth pointing out that I have neither the time nor the energy to undertake the research on PVP that you seem to enjoy.

However after all of that is said and no matter how much longer this discussion continues, I do happen to believe that working on a precise planting action will allow an athlete to continue to accelerate into take off while an inaccurate off balance planting action - characteristic of many vaulters - will cause them to slow down. I base my practical coaching on that philosophy and devote a great deal of time 'trying' to ensure perfection. Readers can make up their own minds on whether this is a sensible thing to do or not. I will certainly be doing that at the clinic I am conducting at Dana Point High School tomorrow.

Incidentally if Roman and I were to spend five minutes discussing this issue I would be very surprised if we did not quickly find either complete agreement or an acceptable middle ground. That is what good friends do.

[vaultman18]

I must say tho, that even between Agapit and Altius, there's disagreement in whether or not you can actually accelerate into the takeoff. I remember Agapit telling me that accelerating into takeoff was a pipe dream.

Kirk

Kirk
You misquoted what Roman said back in 2008 and when Alan said it wasn't true you get mad and demand an apology? I don't get it....

Agapit Said:
"Sorry to confirm this, but you ALWAYS loose speed AT the takeoff, unless you are doing standing jump or maybe one step run up."

Key word of that quote is "AT" and you said "INTO", that changes everything. As I see it Alan is correct and Roman is also correct. You took the opportunity to point out that Alan and Roman disagree when in fact they do not. Why? It seems to me you were/are looking to discredit someone or something, if not why try and make the point that Alan and Roman disagree about something? Again I don't get it.....

[KirkB]

Altius, I accept your most recent reply to this as a "well-written, well-reasoned" reply. Thank you! That's all I was looking for!

Key word of that quote is "AT" and you said "INTO", that changes everything. As I see it Alan is correct and Roman is also correct. You took the opportunity to point out that Alan and Roman disagree when in fact they do not. Why? It seems to me you were/are looking to discredit someone or something, if not why try and make the point that Alan and Roman disagree about something? Again I don't get it.....

The difference between "AT" and "INTO" is subtle, and I could very well have missed that subtlety. And if I missed that, then I'm sure many other readers missed that too. Thus, it was a reasonable question that I asked.

There was absolutely no ill-will intended in my asking for clarification between what I perceived what Agapit said and what Altius said. To infer that I had some devious intent is just plain wrong and pure speculation on your part. And actually kind of an insult - you should know me better than that. I simply wanted to get clarification re acceleration/deceleration at (or near) takeoff. GolfDane ended up being the person that clarified this, after all these rants by Altius (and my rant back to him).

That's it. Be careful not to read more into a simple clarifying question than simply what it states.

Let's strive to keep PVP civil and oriented towards REAL technical issues! Not bashing, false accusations, etc, etc!

Kirk

[vaultman18]

No ill will here Kirk... I have spent a lot of time with Alan and Roman apart and together over the years. I can assure you they do not disagree about much other than politics LOL. I believe a lot gets lost in text and that is the inherent problem with a message board. Although I must say without PVP my coaching career would be much different and I appreciate its value greatly. But at the same time much is lost in translation so to speak. Cheers!

[KirkB]

In Bussabarger's "ideal technique in the fiberglass vault" thread, I posed this question yesterday, but PVStudent (correctly) pointed out that it was the wrong thread for it. Since my question is entirely related to the "correct takeoff point" (and is not a GENERAL question related to Bussabarger's point re "ideal technique", I think this is a better thread for it. Sorry for any confusion.

... the issue of the ‘pre jump’ that I raised with him and is discussed in BTB where he clearly knew what he was attempting to do – he clearly knew how difficult it was to execute and that he had only managed it a few times in his career. ...

At the risk of being accused of trying to cause another riff between what Altius says (quoting Bubka) and what Agapit says (quoting physics), I have to ask (so please don't throw any grenades or stink bombs in my direction) ...

If a free takeoff is a mere millimeter (or thereabouts) off the ground and a pre-jump is something much more substantive than that (e.g. Fefanova's technique), why does Agapit say that anything more than a mere millimeter is inefficient? Or why does Bubka (via Altius) say that a pre-jump would be even better than a free takeoff?

Here's the deal ...

I believe that I had a pre-jump in my day. I was a fairly good vertical JUMPER, and I used this to what I considered my competitive advantage, by jumping vigorously off the ground (and into an exaggerated C or stretch position).

I felt that my best jumps were the ones where my takeoff foot was clearly off the ground when the pole hit (although I will be the first to admit that I may have been a tad under on occasion - but my best jumps felt "out"). So my position (based on what I thought was "good" science) was that a pre-jump was optimal, given my natural jumping ability.

And I felt this way up until recently, when Agapit pointed out that anything more than a free takeoff (I don't have his exact quote, but I suppose I could find it if pressed - here we go again) was sub-optimal, because now you're fighting gravity, and that would be a passive phase that must be eliminated. I THINK I actually agree with Agapit on this point NOW (altho I hadn't thought of that until Agapit pointed it out), but now that seems to contradict what Bubka (via Altius) is saying, doesn't it?

Again, I'm not trying to stir the pot here at all, I'm merely trying to get to the truth of the matter. And by the truth I don't mean what Bubka THOUGHT (I have no doubt whatsoever that Altius is quoting Bubka correctly) - I mean the true physics that the takeoff should be based upon.

A related point is that Agapit was debating with a few of us on PVP a month or so ago about whether or not 100% of the runup went into the vaulter-pole system on takeoff. He said it did, and I replied that there was ALWAYS energy loss on takeoff (caused by shoulder jarring and the transition of horizontal momentum to vertical momentum). He never did answer this. So now I'm wondering if maybe he's making his points (re energy loss and re the pre-jump) based on each specific vault part (or physics principle) in isolation of each other vault part? Could it be that the answer to my questions is that Agapit isn't looking at the PV "system" holistically? Or if that's not it, then what's the correct explanation?

I suppose my question is pointed more towards Agapit, but I expect that Altius will be the one to answer, since he appears to be more vocal on PVP than his friend of late.

And sometimes his spokesperson.

Kirk

[KirkB]

Apologies for the mixup but I have neither the time nor the energy to fix it.

I think you would have been better off to just let PVStudent to reply to my (above) post, as he said he would in the "ideal technique" thread. I expect a much more well-reasoned, well-written reply from him - answering from a "scientific reason" perspective (as he always does).

But instead, you have ONCE AGAIN jumped the gun, flown off the handle, disregarded my specific questions, and managed to insult me in the process. It seems almost like you're trolling PVP, looking for fights to pick. [sigh]

Since you are unwilling or unable to format your reply so that it's at least readable (I don't think it's that you don't have the time nor the energy - you just don't know how), I'm doing this for you ...

If a free takeoff is a mere millimeter (or thereabouts) off the ground and a pre-jump is something much more substantive than that (e.g. Fefanova's technique), why does Agapit say that anything more than a mere millimeter is inefficient? Or why does Bubka (via Altius) say that a pre-jump would be even better than a free takeoff?

Again, I'm not trying to stir the pot here at all, I'm merely trying to get to the truth of the matter.

BULLDUST!

Kirk - I am becoming more and more convinced that you re in fact what we in OZ call a ----stirrer. For some strange reason trying to cause a rift between Roman and my self -or worse still trying to dent one or other of our credibility. Carry on. You won't achieve the former and I doubt too many people will take much notice of your attempts at the latter. Take heed of vaultman18's comments.

I suppose my question is pointed more towards Agapit, but I expect that Altius will be the one to answer, since he appears to be more vocal on PVP - than his friend of late.

If you want to call Roman I can give you his number - I can tell you he is sick of amateur theorists and is not interested in contributing to PVP because of it.

Yes I will answer because I have stated very clearly my interpretation of the free take off and the pre jump - a term I coined after meeting Petrov in 1986 after listening to his description of a free take off = in BTB2. However the fact is that - AGAIN - you have clearly not read the chapter on the take off in BTB -or for that matter any of the posts in which I described/defended the notion on PVP years ago. For you would never have found "One millimetre" mentioned. For me the real characteristic of a free take off - is that the pole is not loaded at the instant the vaulter leaves the ground -this means that the athlete CAN still be in contact with the ground at that instant. The pre jump occurs when the athlete IS in the air BEFORE the athlete leaves the ground - that is what Sergey was referring to in Jamaica - when he indicated he managed it a few times - He was always trying for that but usually had to settle for a free take off.

And sometimes his spokesperson.

Again attempting to stir the pot. Never HIS spokesperson - always a friend with whom I discuss a whole range of issues - but always happy to be Vitali's spokesperson. A role he publicly thanked me for undertaking on the state of Reno Hilton a few years ago.

Please try reading the book - you might learn what I really think, on all of the issues you continue to pursue with some level of ignorance.

[KirkB]

Altius, I think I'll just wait until PVStudent replies to my questions, since I can't seem to get a straight answer from you. You seem steadfastly determined to continue your vendetta against me - for whatever reason, I don't know. I have always supported you and your book on PVP. Why be so grumpy about all this?

Here's a reminder of what I said earlier on this thread re your grumpiness:

Let's strive to keep PVP civil and oriented towards REAL technical issues! Not bashing, false accusations, etc, etc!

I WAS keeping this civil, and this WAS a REAL technical issue that I wanted to get a scientific answer to! You, on the other hand, continue to bash me and falsely accuse me of things that I did not say or infer. AND you continue to avoid the technical questions that I ask. I thought you were an expert on this subject matter, so why not share your expertise, instead of just bashing me?

I said this:

... Agapit pointed out that anything more than a free takeoff (I don't have his exact quote, but I suppose I could find it if pressed - here we go again) was sub-optimal, because now you're fighting gravity, and that would be a passive phase that must be eliminated.

... and you twisted what I said to this:

... you have clearly not read the chapter on the take off in BTB -or for that matter any of the posts in which I described/defended the notion on PVP years ago. For you would never have found "One millimetre" mentioned.

Did I not say that I didn't have his exact quote?

I fully understand that ...

... the real characteristic of a free take off - is that the pole is not loaded at the instant the vaulter leaves the ground -this means that the athlete CAN still be in contact with the ground at that instant.

I agree with that - that is NOT the issue! I cannot believe how much you criticize people re mundane details, yet you do this yourself. I could have just as easily said (and in hindsight, perhaps I should have said) "the instant the vaulter leaves the ground, plus or minus one millimetre". I thought I was distilling it down to less words that were just as clear, but apparently that one millimeter is a lot more important to you than it is to me. Do you realize how much one millimetre is? It's not much more than the thickness of a fingernail! It's not anything that's distinguishable at all!

And I wasn't even referring to anything that YOU said - I was referring to something that Agapit had said.

The pre jump occurs when the athlete IS in the air BEFORE the athlete leaves the ground

OH REALLY?

Come on, Altius, think about what you're saying before you say it! How the hell can he be in the air BEFORE he leaves the ground? LOL!

Please try reading the book - you might learn what I really think, on all of the issues you continue to pursue with some level of ignorance.

Another put-down. Another attempt to discredit me. [sigh]

What you don't seem to realize Altius (though I have told you this, and complimented you on it many times), is that I HAVE read your book, and for the most part, it's good, but I have also found many, many errors and omissions (which I have NOT told you) - it's not as perfect of a book as you think it is. Why haven't I told you that? Because you would instantly take the defensive and ask me for specific quotes that were incorrect - page by page.

So when I ask a question about something, don't assume it's because I HAVEN'T read your book. Rather, it's because I HAVE read it, and I'm looking for clarification of something that's not there, or that appears to be in contradiction with some other expert.

Are you not willing for your writings to stand up to public scrutiny? That is what you're asking of David Bussabarger, so I don't see why you oppose the scrutiny of your own writings - or Agapit's.

Has it ever occurred to you that I consider you and Agapit to be experts, thus I'm leaning to both of you to clarify your statements much DEEPER than what you may have originally stated - in your book or on PVP?

What do you want to be known for? An expert on PV technique or a PVP bully?

Kirk

[altius]

Enough - I am done. Cant waste any more of my time on this. You carry on as much as you like. The book and the dvds' have been out there many years for all and sundry to critique. If you write a book taking on the myths and mythology that surround this event then you expect it - fortunately with 4500 copies sold of both books - along with thousands of dvds, where I was brave enough to show my own kids jumping - the positives more than outweigh the negatives. So you carry on with your games - and "your search for the truth" - which is nothing more than you attempting to stroke your ego.

I get mine stroked every time I do a clinic!

[PVstudent]

Backround to the Issue: The Correct Point for the Take-Off in modern pole vault technique.

The first official use (sanctioned international competition) of the forerunners of the modern flexible pole (composite material poles as opposed to the flex possible with Bamboo poles) was in 1952 by Bob Mathias and then George Roubanis in the 1956 Olympic Games, Melbourne.
From the hall mark year1960 until the present I define as, the era in which pole technology and manufacturing of flexible vaulting poles played a significant part in enabling vaulters year by year to steadily raise the World Record.
Starting with the records of George Davis in1961 and John Uelses in1962 progression came to an abrupt halt at the high plateau achieved by Sergei Bubka’s World Outdoor Record of 6.14m of 1994 and World Indoor Record of 6.15m set in1993.

http://youtu.be/ObkN0gU5Jck

As the fortunes of USA, Soviet, Polish and French vaulters have waxed and waned the take-off techniques these vaulters used continues to be controversial.

The current thread is yet again debating the varying interpretations of free versus pre-jump versus under take-off concepts of the take –off technique as a key to unlocking the capacity of current elite male and female pole vaulters to surpass the current officially ratified World Records.

The question posed to me on this thread started by Kirk is:
“PVStudent, if you would be so kind, I would appreciate your reply to this - as you promised. You did clarify the free takeoff quite thoroughly in this thread, but you have yet to answer my question re the pre-jump confusion that I have (which is actually in this "What is your correct takeoff point?" thread: there, I have posed a serious, technical question that deserves a serious, technical answer. Thanks in advance."

The Specific Question Kirk asked?

“If a free takeoff is a mere millimeter (or thereabouts) off the ground and a pre-jump is something much more substantive than that (e.g. Fefanova's technique), why does Agapit say that anything more than a mere millimeter is inefficient? Or why does Bubka (via Altius) say that a pre-jump would be even better than a free takeoff?”

http://youtu.be/y9Q4rL0PC-s

Classic Free and Possibly a Pre-Jump Take-Off!

Bubka Free Take-Off.jpg (109.47 KiB) Viewed 40849 times

Before I can seriously give my technical response there is a lot misunderstanding of the vaulting facts that are as researchers P. Vaslin and M, Cid in, Les facteurs de la performance en saut ā la perche dans la litérature scientifique call “les facteurs indiscutables ” that I have to disentangle.

I answer the question posed first by clarification of my preconceptions of the pole vaulting process and then will focus the lens of that perspective specifically on the take-off.

“On ne reçoit pas la sagesse, il faut la découvrir soi-même après un trajet que personne ne peut faire pour nous, ne peut nous épargner.”
“We are not provided with wisdom, we must discover it for ourselves, after a journey through the wilderness which no one else can take for us, an effort which no one can spare us.” MARCEL PROUST.

The quotation above and videos cited below provide an embarkation point for a voyage from the distant past of 1920 and finishes at the end of the 1980’s. Along the route there are signposts for those with eyes to seek them out and furthermore to recognise the milestones along the evolutionary road of flexible pole vaulting take-off technique.

The videos provide an objective empirical data base of recorded images of many (selected and therefore acknowledged as biased) of the World’s greatest exponents of the “Art of Pole Vaulting” performing at the pinnacle of their prowess in the era leading to the concept of the Free Take-Off as revealed in 1985 by Vitali Petrov and the Pre-Jump by Alan Launder in 1989.

http://youtu.be/w3UTcP5YUCA
http://youtu.be/HyHHN-XvtvI
http://youtu.be/QR5bauUM1ik
http://www.youtube.com/watch?v=elTvktlimMc
http://youtu.be/9_hzB33V8wE
http://youtu.be/SS1mctHgeXE
http://youtu.be/CHnIUaLUdBo
http://youtu.be/sach2OkFw4I
http://youtu.be/oenHR-GAq3Y
http://youtu.be/-DSL06OyY94

Having viewed the videos of the pole vault technique time capsule,it is evident that many coaches and athletes of the pre Bubka era, especially in Eastern Europe (Poland, The Soviet Union and East Germany), had, by 1983, abandoned the notion of pole vault take-offs with wide grips and the associated deliberate bending of the pole during the propulsive thrust whilst in ground contact during the take-off.

However, anecdotal evidence and more recent video recordings would suggest the majority of elite vaulters, particularly in the USA and France, (an assertion on my part) continue to “actively bend the pole” at some stage in the take-off foot ground contact time.

http://youtu.be/_Agh6AaJlwI
http://www.youtube.com/watch?v=XHfI6OT7ap8
http://youtu.be/9dpzGOAu6bs

(Elite pole vaulters I define as those who in any single year, between the year 2000 and 2012, were ranked by the IAAF to be in the World Top 20 male and female exponents of this athletic discipline.)

In the 1960’s to the early 1970’s it was widely advocated that in the propulsion phase of the take-off the vaulter should deliberately initiate some pole bend whilst in firm ground contact during the take-off.

The classic source of wisdom of the 1960’epoch is in R.V. Ganslen (1963) Mechanics of the Pole Vault. (5th and 6th editions) confirm that this notion was widely accepted and strongly believed, based on reports of vaulter’s opinions and their interpretations of their empirical experience as recorded in this highly influential and broadly disseminated vaulter’s Bible!

Today, we must not forget the changing state of the art of fibre –glass pole manufacture at that time was such that the poles could be unreliable, inconsistent in recoil, had high stiffness along with the heavy weight of the poles influenced the empirical experience of the vaulters and coaches.

The empirical experience of vaulters of that period strongly confirmed their “belief” in deliberate bending of the pole during the ground contact of the take-off. They also believed the pole weight was best managed by a wide grip, a low angled, almost horizontal pole carry throughout the approach run.

What then was the state of belief / understanding concerning the take-off amongst some coaches in the USA circa the late 1970’ and early 1980’s? During this period the fibre –glass poles were becoming more reliable, more flexible and more widely accessible in Western and Eastern Europe.

Guy Kochel in the USA, coach of Earl Bell, has this to say on the take-off in 1981 in Practical Coaching Techniques for the Pole Vault. Publisher, Championships Books, Ames, Iowa. (Pages 13-14) and I quote verbatim...

(pp: 13-14)... “The take-Off

There are many variations of the take-off because there are many differences in style, grips, speed and physique. The take-off should not require conscious thought, but should become an automatic action through the repetition of drills (which develop confidence).
During the take-off the vaulter should feel that he is too far out from the box. Although take-off may depend on some individual differences, there are certain basics required for a good take-off:

1. The top hand should be directly above the take-off foot.
2. The lead knee (right for right handed vaulter) should have a quick hard drive in leaving the ground. The drive is forward and upward.
3. The right arm should be as high as possible.
4. The left arm keeps the pole away from the body, but will collapse at a point to a right angle. This left arm is then the control point of the vaulter.
5. The left (take-off foot) should keep as much split as possible as the right knee drives upward. The left leg should stay as straight as possible. This slows the vaulter’s swing, but accelerates the speed of the pole.
Most good vaulters actually sprint off the ground and drive upwards with the arms. This enables the vaulter to get a higher plant and increase the angle between the pole and the box which helps the vaulter’s momentum.”
(Indication in bold has been added by me and did not occur in the original)

I have outlined, by reference to a visual database record and an extract from a very successful USA Coaching Manual on Pole Vault, a précis of the state of empirical knowledge of pole vault technique of the late 1970’s to early 1980’s in the USA.

Critical qualitative analysis of the video recording evidence in regard to the take-off component of the performance I referred to, will allow readers to judge for themselves what they consider the state of play to have been.

The samples, though not representative of the total population of vaulters of that time, do give some visual indication of the performances of USA, French and Soviet vaulters as to how they managed pole vaulting with the aid of a flexible pole.

This evidence I have provided as background to flexible pole vault take-off technique in this post I hope establishes a sufficiently factual basis to allow me to identify some indisputable facts that I will use to underpin my answer to Kirk with specific reference to the Pre-Jump in my forthcoming series of posts.

My stance on the Background to the Correct Take-Off Issue will follow in my next post where firstly I identify what the primary flexible pole vaulting objectives are from a coach and athlete perspective.

Secondly, I propose an analogy I hope will help to eliminate argument about style from clouding the technical proficiency aspect of the correct take-off issue being discussed.

[PVstudent]

State of the Art Just prior to the emergence of Sergei Bubka.

The illustrations below depict performance technique Models current in 1970's Soviet Model of Pole Vault.

Model pre Petrov-Bubka 1970's (Jagodin).jpg (55.05 KiB) Viewed 40821 times

The Model for the USA vaulter Dave Roberts shows the technique advance of the technique around the end of the 1970's.

model USA Dave Roberts 1979.jpg (55.92 KiB) Viewed 40821 times

Another USA vaulter, Mike Tully was demonstrating a take-off emphasizing the jump upward in the take-off and immediate very forceful swing on take-off.

http://www.youtube.com/watch?v=ALs9EDHKP_0

http://www.youtube.com/watch?v=QR5bauUM1ik

At this point I think it is appropriate that I introduce an analogy between pole vault and an Elite Musicians Soloist competition to point out more clearly that the take-off in pole vault is not a matter of personal style, nor does the performer have any choice on how best to overcome the challenge this task places on the total success of the pole vault outcome.

Pole Vault Performance Invariant Elements.jpg (101.01 KiB) Viewed 40821 times

The diagram shows the invariant sequence of elements (the test piece score of the musicians competition) that all pole vaulters must perform.

Maestro (Coach) and the Artist Performer (Vaulter), attempt to achieve the highest level of performance technical proficiency in the Art of Pole Vaulting. Unlike the artist’s performance there is an objective indisputable measure to judge the success of the work of the pole vaulter.
The best performance and winner of the contest clears the highest bar compared to the other artists attempting to play the same score (a number of repetitions being required) on that day, at the same performance venue and in the time order of starting that is pre allocated by lot. Maestro and the Performing Artist retain control of when to start in the competition and also make choices on the number of repetitions of the score to play.

(If you think my analogy is off the mark, consider the highly “cut-throat” intensity of the international competitions for musicians vying to become recognised as solo performers and the teaching and practice required to reach the proficiency to enter them! These musicians are passionate, practice as much as 6-7 hours a day, start their musical journey at a very early age, and are continuously testing their musical prowess before audiences and judges over many years.)

In pole vaulting the test “the equivalent of a musical score” is always the same for all the artists performing on the day of their competition. There will be many “stylistic” variations on display depending on the unique physical, mental qualities and technical proficiency of the pole vaulters (performers).

In the Pole Vault the score to be performed is indisputably fixed for all artists from day 1 until the performing artist ceases competition and is always the same invariant score. That this is so is dictated by universal accepted rules under which the performance attempts will be made. The contestant must attempt to perform the complete score in its entirety. That this point has been reached is indicated by an official observer raising a flag coloured white if the bar is negotiated correctly or a red one if the attempt is a failure. Equipment failure during a performance of the score entitles the performer a re-attempt to perform the vault (the score).

Throughout the performance of the fixed (invariant) elements of the score the vaulter is free to improvise and make choices in the performance movement technical qualities in combination with those of the vaulting pole chosen for a particular rendition of the score.

In making these decisions the vaulter seeks to achieve the most harmonious match between themselves and the pole that will optimise completion of the compulsory elements of the score.

The winner of the competition is the one who manages these decisions the best by clearing the highest bar in the competition.

The two instruments involved in any pole vault performance are vaulter and pole.

The choice and performance of the type of pole is chosen by the performer and can be changed in the repetition of performances of the pole vaulting invariant score.

As with all musical instruments, vaulting poles vary in quality of performance according to make and design characteristics as well as manufacturing fidelity.

The Pole Vaulter artist has to learn and practice daily, over an extensive period of time (2-3 hours practice daily for some 10 -15 years), how to integrate their body and the implement (the instruments used to play the score) in order to become able to reliably and consistently play the score as perfectly as is possible under the circumstances.

The Maestro should not only know the score (every minute detail of the event, what is required of artist in both body and mind, understand how the vaulting implement must be played to extract from it what the performer requires) but be adept at observing, analysing, instructing and guiding an artist to achieve a performance objectively measured as being of the highest quality (max height jumped within the rules, no style points in pole vaulting!).

Perfect rendition of the Score is recognised as the World Record in Pole Vault.

Whilst my contribution will be based primarily on Biomechanics of Pole Vault specifically focused on the take-off readers should not lose sight of the fact that the discussion is intended to assist coach (Maestro) and vaulter (Apprentice Artistsan).

This is a challenge in this forum because many of the discussants use the argot of the pole vault fraternity (Slang, Jargon and as such can be taken by those of us not privy to the arcane knowledge?/ignorance? it covers makes it unintelligible) in a manner akin to the statements of fortune tellers.

Such conformational bias is extraordinarily difficult to dispel when it is so entrenched (there you are, I am exposing my prejudiced judgement from the outset!).

Having set the background and established a contextual reference frame for the journey I will start with the first step being clarification of why working with a flexible pole facilitates longer grips lengths by vaulters of different statures, body morphology, and physical abilities.

My next post will identify some of the established facts ie., those matters about which there can be no dispute in regard to pole vaulting take-offs!

[grandevaulter]

Excellent historical footage. Thank you for sharing this !

[PVstudent]

Pathway of the vaulter centre of mass the key to flexible pole vault techniques

Energy exchange on the pole 9.jpg (121.39 KiB) Viewed 40769 times

The diagram above shows the fundamental facts of the post take-off advantages of the pole being able to flex (bend) due to the loading impressed upon it by the weight (-mg) and the forces due to muscular effort of the vaulter.

Key Facts (points generally accepted to be beyond dispute) in regard to advantages of a flexible pole to modern vaulters:

• The curvilinear displacement path of the vaulters centre of mass enables the vaulter to do more mechanical work over a greater distance than is feasible on a “stiff” pole whilst gripping the implement (instrument / tool) at greater grip distances along the pole from the pivot axis of the pole connected to the planting box.

• The flex of the pole occurs in 3 dimensions which allows the vaulter to continue the total system linear translation in the fore-aft (sagittal) plane as the pole initially bends between the pole tip transverse axis located in the box and the vaulter’s transverse axis through the wrists at the grip end.

• The lateral deflection of the pole about it’s vertical axis, shortly after the vaulter takes-off , makes possible even further linear displacement forward of the vaulter towards the plane of the bar.

• Bending and lateral deflection phase, because the pole tip pivots in contact against the rear wall and bottom surfaces of the planting box, provides a further opportunity for the vaulter to do more work by generating a very powerful swing from the hands gripping the pole over a greater amplitude. The increased amplitude, in conjunction with increased centripetal force of the swing, contributes additional strain and compression induced elastic potential energy in the pole.

• Power output by the vaulter (rate of doing work = force x velocity and torque x angular velocity: also can be considered as the amount of energy (work) expended per unit time) determines the amounts of pole bend and hence potential energy storage due to the compression and tensile forces acting on the pole as in bends and simultaneously deflects about a perpendicular axis though the pole tip in the time period from take-off to maximum pole bend.

• There is more time, as well as amplitude for a more dynamic whole body swing about the pole grip wrist axes when a flexible pole is being used, for the vaulter to do more muscular work in the time between take-off and maximum pole bend to raise their centre of mass closer to the hand grip locations on the pole.

• During the time between take-off and maximum pole bend the chord of the pole rotates through the same angular displacement as it would for a stiff pole at the same grip distance from the pole tip pivot point.

• Due to the chord length shortening to its minimum at the elapsed point in time of maximum pole bend the rotational inertia about the pole tip axes in the box of the total system (vaulter + pole) in flexible pole vaulting is LESS than on an equivalently gripped stiff pole.

Flexible pole enables the vaulter to have the time and movement amplitude to do more powerful muscular work on the pole

Model of energy input throughout the vault.jpg (83.44 KiB) Viewed 40760 times

http://youtu.be/YP2pvX_cMiQ

The advantage this provides the flexible pole vaulter is three-fold.

(1) The total system, for the same vaulter applied rotation producing forces, rotates faster about the pole tip axis due to the relatively smaller moment of inertia of the total system.

(2) A portion of the energy this reduced moment of inertia saved in “the forces required to drive the total system” to achieve the same chord angular displacement in the time between take-off and maximum pole bend, is available to the vaulter to generate greater swing speed (angular velocity)about the grip axes on the pole.

(3)The bending pole, because it keeps the moment of inertia of the total system smaller, about the pole tip axis for a longer time than would be the case with the equivalent grip on a stiff pole, the vaulter gains the advantage of being able by means of the propulsive swing to;

(A) Drive the total system more efficiently (more linear and angular displacement from the same equivalent input of force and torques to the total system).

(B) Better orient the vaulter’s body towards a greater amount of inverted body location on the pole with respect to the action line of “thrust” delivered via the hand grips at the commencement of the pole recoil.

(C) Maintain a larger moment of inertia about the grip axes of rotation such that the tangential velocities at the vaulters centre of mass and trail leg foot (take-off leg) propel the total system forwards and upwards with the forward effect being greater than the upward until the pole chord has rotated through a 45 degree displacement. After this 45 degrees of chord rotation the vertical effect of the swing dynamic effort becomes pre-dominant.

Model of flexible pole vault post take-off

Model Petrov-Bubka PV student 3.jpg (107.08 KiB) Viewed 40769 times

Coach and vaulter therefore need to consider how the take-off technique they adopt, will develop and train the vaulter’s ability and capacity to increase the probability of achieving all these advantages (and more ) in using this amazing instrument the flexible pole vault pole.

Understanding the technology and the properties of composite materials in modern pole vaulting poles is vital in deciding how the take-off can “ideally” / best be “tuned” to meet the needs of the individual vaulter.

See for example: Hoepffner J., June 14th 2012. Models for an alternative pole vault.

(The paper is available on the net, but readers are advised it requires a sound knowledge of mechanics, mathematics and some basic understanding of sytems control theory. It is of interest I believe to those with an engineering background and interest in the oscillation behaviour of pendular spring mass systems.)

The journey has led from the past to get a quick glimpse at the dramatic transformation of the performance advantages that the modern flexible pole offers. The next leg of the journey will take us to see the vaulter and the pole at work. Be warned, whilst we shall see some harmony in action notes of discord will be ever present!

In my next post I will consider some of the facts of the pole vault take-off and provide some guidelines to clarify what happens to both the pole and vaulter and introduce the observer visual recognition problem in identifying advantages / disadvantages between free and pre-jump take-off techniques.

Readers please bear with me!

It is taking a huge amount of time and effort to prepare the material I am presenting. To communicate about it, because of gulfs in experience, fundamental knowledge base as well as getting past our pole vault sub cultural biases as revealed on PVP, is difficult for me.

Bull dozing my way through would only stir up more confusing “.... Dust.”

This is why I am ploughing the field thoroughly before I can sow the seeds that will reveal my answer to Kirk’s question in regard to the pre-jump.

I want those seeds to be planted in properly prepared grounds of mutual understandings based on empirical knowledge assisted by specifically appropriate and accessible scientific input.

I apologise for the slowness.

I hope I am keeping on topic and keeping my response evidence based, as much as can reasonably be expected, and will get down to the “nitty gritty” once the tilling phase is completed.