Free Take-off???

[dj]

good morning

dj how are you

i've been thinking about the MID thingy and have come to the conclusion that i like it. It is an extension of finding the correct position at takeoff.

As you clearly know one person can reach the correct takeoff point in a better position and with a better tempo than another so simply using the takeoff on it's own does not provide enough information.

I lived in perth for a few years and trained under Steve Rippon alongside Jimmy Miller and Paul Burgess. I got to see Budgy develop from soon after he stepped off the gymnastics mat and i listened to Jim snore nightly one meter from me in Finland for a month. Budgie was in the next room with Rippo who apparently didn't snore quite as much. Wrong combo for me and Budge.

The point of this is that whilst in Perth there was a lot of biomechanical analysis done. Also Nick Linthorne was training in the squad and his interest in biomechnics as many know is very high. The upshot of this is that the scientists needed to also measure take off velocity as well as velocity at ten meters out from takeoff. I'm assuming this information went along with take off position and was used to determine if the parameters were correct or not.

Possibly this MID system disables the need for such testing? If a MID is known to be relative for an individuals grip height and takeoff position then there is immediate feedback for the coach as to whether over or understriding has occurred. Of course this requires that something like the difference in grip heights between Chistiakov and Huffman are relative to the difference in their take off and MID positions. Can you check that information out?

Still having said all of that i believe a coach should have developed the 'eye' for coaching sufficiently to be able to visually know whether the athlet is over or under striding, whether the athlete can be quicker or whether the athlete should drop the intensity slightly because strain is becoming evident. These are only the broadest factors to be considered as well.

So i guess if a coach does not have this 'eye' also developed then reliance on a systematic approach appears to be the next safest bet. How would you describe your own coaching in this way dj?

volteur

unless i missed something you just described it all.. for this and the "MID" MARK post...

the chart simply puts an athlete very near where they should be at 6 strides to run correctly and grenerate the "force" to use that grip effectively.

thank you

dj

[volteur]

Posted for PVstudent by master:

I believe we are getting somewhere closer to understanding the concept of the "Free Takeoff" so that we can have clearer possibilities for unbiased discussions about the Petrovian concept. The question remains of the pole vaulter's intention so that a perfectly Free Takeoff can be achieved. Intention always preceedes action. Hence I repose the question with respect to the evidence revealed in the pictures 1-4 (including some reference points to help viewers more carefully analyze what is taking place since the camera motion and parallex error must be allowed for). Why do you consider the takeoff not to be a Free Take Off with a Pre Jump?

The pole I believe has made contact with the apron (sloping surface) of the box in picture 1. Also I perceive Bubka to be springing upwards as the Bubka-pole system is being translated horizontally forwards until the pole has impacted the back of the box, which has clearly occurred by picture frame 4. I do not perceive Bubka's foot to be on the ground in picture 3 (Why can the sole of his shoe be completely visible?). I also see a straight pole in picture 3.

I hope the indicators I have added in compliance with Volteur's request will serve to focus more exact analysis of this Bubka Take-Off. Agapit's suggestion that the Free Takeoff and Prejump (when properly executed) can appear to be the same thing is I believe reinforced in this example. Unfortunately we do not have the forces being measured under the pole tip that could put the pre-jump issue to rest.

Certainly a Free Takeoff. Is there a pre-jump before the pole tip impacts with the rear of the box?

I also feel that we are getting closer to an understanding of the free takeoff. This discussion and the use of these still photos is really allowing us to hone in on what it actually contains. I agree and disagree with your post PVstudent, however, I really like the phrase 'intention always precedes action as i believe this to be true.

I agree that in photo 1 the pole is on the apron of the box. The point of the partial bend in photo 3 has been made and needs to be analysed further and the the fact whether his toe is still on the ground in photo 3 also needs to be analysed. The pole is definitely in the back of the box by photo 4 the question just remains if this has occurred by an earlier photo.

The partial bend is not fully explained for me by the weight of the pole being levered slightly against Sergei's left arm pressure. I feel that the partial bend is mostly related to the pole being in the back of the box. So i see the pole tip as being fixed by photo 3.

The fact that it is in the back of the box means the pole tip is no longer moving forward at this point. Also of importance is that his left toe never moves forward throughout the entire 4 photos even those every other part of Sergei does move forward. So his left toe and the pole tip are fixed from very early on in the takeoff, yet the takeoff continues and the relationship between the vaulter and the pole continues to change even though some elements are now fixed.

I believe that Bubka is attempting to keep the pole tip from compressing itself fully into the back of the box whilst he completes full takeoff position.

The rest is pretty academic after this assertion. The sole showing of his shoe in photo 3 is more of a function of hip rotation affecting some left leg rotation. The right hip is being actively driven ahead of the left through the takeoff leading to this more extreme hip rotation. By photo 4 this hip rotation has corrected, as the left foot finally unloads from the ground the left hip is 'squared up' again with the right.

Photo 3 does show some loading to me through the toe section of the foot. The curvature of that section indicates to me there is still some weight being loaded through the foot. The fact that his left toe has not moved forward from photo 3 to 4 indicates that not enough time has passed sicne it left the ground to move forward. Any distance created vertically there would also show some forward movement due to the high forward velocity. It doesn't show this so my only conclusion is that the toe is so close the the ground in photo 4 it has barely left it.

finally i found it interesting through golfdane's closeups to see that from 3 to 4 his elbows continue to move forward at the same rate they previously were. The most dramatic change from 3 to 4 is in the relationship of the hands to the rest of the body.The clearest way to see this is to compare elbow and hand positions. Could someone add reference points for these?

cheers

Volteur

[PVstudent]

Following my previous post on the topic of the Free - Takeoff I want to share with PVP my summary in regard to responses from Golfdane and Volteur and my additional information on both the Free Takeoff and Prejump. The full version with all its photos is too large for a single post so it is made available for downloading as a pdf file. Get the pdf file here.

I also provide Pole Vault Power with what may be a World first! Namely force platform recordings of a prejump.

However the first prejump officially recorded, using high speed cine - film, was by Lesov of Bulgaria at the inaugural IAAF World Junior Championship held in 1986.

What the force records show is that once the pole contacts the box and is sliding in it, there is some vertical reaction force upwards during the slide and therefore the pole is NOT UNLOADED before contact is made with the rear wall of the box (Peak vertical reaction force recorded during the slide was 137N (about 30.72 pounds force).Similarly, in the so called Free Takeoff the pole, if it is in sliding contact prior to impact with the rear wall of the box, will also experience some vertical loading.

Another important feature to emerge is that the Free Takeoff or the Prejump cannot readily be distinguished unless the recording resolution is at or greater than 100 frames per sec level of photographic resolution. Indeed the human "eye" unless it is biased by expectancy or preconception is unlikely to be able to distinguish Free Takeoff from a Prejump from readily available still or moving images. Time for visual reaction time to an expected event is 180 to about 200 milliseconds, but much longer for an unexpected one. Even knowing what to look for, conscious perception requires much longer viewing time to make an accurate differentiation in real time when viewing actual vaults. Also if you don't know what you are looking for the brain is very accomplished at providing what initially appear to be plausible answers by filling in the gaps in the available sensory input of the viewer.

Also, since pole vaulters capable of performing a Free Takeoff operate in an open loop feedforward mode of motor control, by the time kinaesthetic feedback reaches the vaulter's brain about 60 to 120 milliseconds will have elapsed. That is by the time the vaulter's brain auto pilot becomes aware that the take off was executed correctly the vaulter will have moved on 60 to 100 milliseconds further in time and is by then well advanced in the pole support initial phase. For this reason it is not unreasonable for the vaulter to adopt a strategy of attempting to "Prejump" in order to time the instant of loss of contact of the take off foot to be directly below the top hand in the precise time and spatial location to optimize the final energy input exchange from the vaulter to the pole and at the same time projecting their centre of mass forward and upward i.e. "A prejump can be operationally defined as a slightly prematurely performed Free Takeoff!" The degree of prematurity is in the order of milliseconds only i.e. The sensitivity of the measurement system resolution must be high enough to reliably detect differences + or - 2millseconds (practically and economically feasible). Coaches can and do make the discrimination by filling in the gaps in their perceptual pick up during observation. The accuracy of the analysis I suggest can only be capable of confirmation by using measurement systems of sufficient precision and sampling rate.

I still disagree with Volteur and assert that I perceive Bubka's toe to have broken any effective contact with the ground in Frame 3. I agree that the horizontal location of the toe tip does not change but its vertical location does.

I present some photograpic evidence to show the bending effects of holding a pole with the arms raised and standing on one's toes as to how bending moments operate. These results support Golfdane's suggestion as to localised bending via pressure upwards through the left hand. (note: This is not saying that the left hand is attempting to be actively pushed upwards against the pole.) What I am suggesting is that the reaction to the bending moments is seen as slight pole bend and not necessarily due to impact of the pole with the rear wall of the box).

Following my summary review I present further examples of a Free Takeoff from a Russian analysis of pole vault by a highly respected world famous coach.

I then present PVP readers with some further challenging examples (that may or may not be Free Takeoffs) to consider and finally present force platform recordings showing unequivocal evidence of a prejump.

So that I can sharpen my knowledge and understanding I invite readers to respond and provide their definitions of a). Free takeoff and b)Pre-Jump

I look forward to reading your thoughts on the matter. To ensure clear communication reference to the specific examples, given in the linked PDF file, or any better or clearer examples you can provide would be appreciated.

[decanuck]

Wow. Outstanding post, PVstudent. Your photo array irrefutably proves Bubka pre-jumped in that sequence, and the shots of other pre-jumpers are intriguing.

Could you further explain what is meant by the phrase, "The peak reaction force during the slide is 137N." Does this suggest that the pre-jumping not only prevents a vaulter from losing energy into the box, but, in fact, adds energy to the vault (to the order of 137N in this case)? For comparison, do you have data of this kind for a jump that was under and not free?

[golfdane]

Wow. Outstanding post, PVstudent. Your photo array irrefutably proves Bubka pre-jumped in that sequence, and the shots of other pre-jumpers are intriguing.

Could you further explain what is meant by the phrase, "The peak reaction force during the slide is 137N." Does this suggest that the pre-jumping not only prevents a vaulter from losing energy into the box, but, in fact, adds energy to the vault (to the order of 137N in this case)? For comparison, do you have data of this kind for a jump that was under and not free?

Yeah, outstanding!!!

"The peak reaction force during the slide is 137N."

It's the force exerted from the dropping pole (unless the jumper is pulling with his lower hand at this extremely early phase). If you slam the pole down, would the vertical force on the apron increase, but it would not benefit your jump.

[vault3rb0y]

Seriously, this is amazing. I feel like a drug addict that just got his fix with that post/pdf. Really great stuff! I think we need to use the force platform recordings more than we do, i dont care what it costs .

My definition of free take off-
A take off in which all horizontal momentum is converted and transfered into stored energy in the pole.

Pre-Jump
Free take off in which the vaulter leaves slightly earlier than in a free take off, giving more time to increase box angle with the pole, and set up trail leg more efficiently.

After reading that stuff, i dont know what it really is! I didnt realize how over simplified and even innacurate my definitions may be.

[agapit]

Thank you for the post. It is very good. I just wanted to point out that on the pic #3 both of his arm are slightly bent.

Cheers!

[tennpolevault]

since you guys are talking free take-off. I thought I would present this video of a young vaulter I am coaching. He naturally likes to take-off way out. About 13-6 to 14 from 7 lefts. He is just learning how to manage this without "sinking". He is quite a good leaper. He is a decathlete. As he learns the vault, it is interesting to see how quickly he improves when I use petrov type analogies with him. The earlier he gets pressure down the shaft of the pole and the faster he works his arm, the better his vault looks. He likes to keep things moving which I think is good. I am very hesitant to teach him stiffen up his left arm or create other affectations which do not result into adding energy into the pole or into rotation. This video clip is very short run and small pole so it doesn't give him much back. I think if he can extrapolate things out to 4.90 poles it could be scary in the years to come. Here are stats:
100m: 10.90 ish
LJ: 7 metersish
HJ: 2m

DJ.......here are his marks on the runway so he may still be shortening his stride length too much: (7 lefts)
Mid- 49.5
TO- 13' 3"
Grip - 15' 2"
Bar cleared: 5.05m

http://www.youtube.com/watch?v=e18VrUBYVys

[volteur]

Thank you for the post. It is very good. I just wanted to point out that on the pic #3 both of his arm are slightly bent.

Cheers!

Cheers i hadn't noticed that bit.

PVstudent, great post. Excellent preparation and argumentation. The main issue i am having with it is that your recording of the 5.40 the vaulter in question jumped 70cm below his best. It's not a true test because of this. Do you have any more readings from the same vaulter on other jumps? Higher jumps. Heights that have to test him?

Re: Markov. It is Markov's intention to pre-jump. Because Markov pre-jumps he has continuity issues later in the vault. Awesome athlete though.

Can you tell me if these vertical reaction forces are from the pole hitting the floor of the apron?

I do agree there that some of the bend in the pole in photo 3 is from the weight of the pole bending around the left hand as it acts to stabilise and create direction. It is like the front hand when shooting an arrow from a bow. Stablising and creating direction, not pushing, but i think we are all agreed on this point now.

The rest of the bend is from the partial pressure back from the pole. As agapit pointed out this is already creating pressure against the vaulter in photo 3 as evidenced by the slight backwards movement of the hands in relation to the elbows from 2 to 3. Bubka and Feofonova are quite similar in timing and intention at this stage of the plant. They both appear to have the very similar timing relative to when this localised bend occurs in relation to toe-off and hand-support.

I wish we had clearer photos although it still looks clearly to me his foot is not in the free and vertical stage of the vault until photo 4. His toes definitely look like they are resting on the ground still in photo 3 to me.

Having said this it has been clear for me for years now that the pressure must be continuous from toe-off to hand support. The intention was to transfer my weight from my left foot directly to my right hand. The standing 1 step-drill is all about teaching this very aspect.

Just regarding the information on perception of the eye. What you are talking about is the reactive ability of the eye. When new unsuspected information is processed there are time lags such as you mention. This is not the only way our eyes/mind perceives. We can also plan ahead and thus be ready, we don't have to just react. So the coach can 'already' be looking and therefore notice something as it happens ie be looking before it happened, whilst it is happening and after it happened. No reaction ability needed.

As for definitions of the two i think this is a really tough one but will have a slight crack at it

Free-takeoff - where full postural extension and optimal forward momentum are achieved at the point of take-off whilst minimising resistance being met from the pole.

Pre-jump - where the vertical component of the takeoff is over-emphasised relative to it's horizontal component, however, in the other aspects, it 'can' be the same as the free-takoff.

[baggettpv]

Hey TP,
Forget the mid stuff. It will occur. Teach this guy how to do 2 things now. One is to jump efficiently (without a pole) and the other is to plant the pole from a jump.
Too much time is spent on the end results in this forum and not enough on how to get there.

Rick Baggett
WSTC LLC

[baggettpv]

I explain it well on youtube and my "Groundwork" video. And also running mechanics for the vault. Search youtube for my name.

Rick Baggett
WSTC LLC

[baggettpv]

To all guys and girls out there, just a reminder. Speed is a function of stride length and turnover rate. Stride length can be improved greatly, turnover? About 5% (based on research). So now if speed is really gonna be based on stride length then what to do for this? That is the question it is. The mid mark is based on what? An efficient run or not? DJ what do you do for this? Just let them get stronger with poor running mechanics? My speed development procedures are available and widely copied.
I am just trying to make it real compared to what? 24 years of teaching......

Rick Baggett
WSTC LLC