Mid Mark Chart

[dj]

good evening,

powerplant42 .. honestly i think you should either get serious or remove yourself from the thread..

don't believe we have any 10' or 2' pole vaulters.

dj

[sooch90]

So hypothetically, if somebody 10 feet tall or 2 feet tall were to be holding at 17'1'', then their MID would still be 58 feet. How does one account for take-off measure with these situations? Would the MID really be relative to take-off, not necessarily the back of the box? I understand that for most people the take-off point is not a problem, but just hypothetically for my own understanding...

Correct me if I'm wrong, but IF a person 2 feet tall had the ability to grip 17', then he (or she) would have to be an extremely, ridiculously fast person. So although this person has very small feet, the distance the person covers between each stride is greatly increased because he's going so fast?

On the otherhand the 10' person would have very long legs and a very very tall plant and takeoff. If 17' was his max grip that he could hold, then he would be somewhat of a slower person, so each of his strides would cover much less distance because of his slow speed.

This is assuming that both athletes run without overstriding.

[volteur]

hello

Yet if the coach has a sufficiently developed 'eye' then the chart does become redundant for that coach. I feel Agapit is such a coach.

i have not found this to be true.. even the best 'eye' can use some "conformation".. sometimes more so.. "suttle" changes sometimes exhibited by worldclass "Thoroughbreds" is even more difficult to observe.

sorry but agapit does not use it or understand it....those that feel a 60 foot "MID" is ok and that the length of the legs makes a difference in how speed is created does not understand correctly........

dj

Hello again

I have found it to be true though. Surely you would say Petrov is such an individual. Would you say Bubka already covers what the MID chart would teach him?

I mean if you look at technique instead of runup, there is no mechanical structure like the MID chart that can refine things enough. Definitely not enough to create a Bubka in action. And i have to assume based on reason that if Petrov has the ability to fine tune Bubka's technique to the level it is, then he has the same ability to fine tune the runup as well.

Whether Agapit is an equal to Petrov is probably not yet debatable. But on the scale of coaching capacity i see Agapit as occupying the saem end of the spectrum as Petrov. I am convinced of this for two very good reasons. One is he understands and explains things in pole vault clearer than i understand them. So in this sense he helps my own understanding move forward. The other is that he has proven his coaching methods with excellent results. Double whammy.

So in the end i feel your chart can be invaluable for the beginner and intermediary coach, but for the advanced coach it will slip into the background as his own 'sense' of pole vault passes the accuracy provided by any mechanical structure - including your very accurate chart.

volteur

[agapit]

if a "MID" of 57'5" with 9.9mps of speed at the takeoff is correct for Bubka to jump 20'2" .. it seems to me (logic and/or science) that a "longer/slower" stride (an indication of much more "ground" time and a greater parabola) would not be the correct way to run to obtain greater speeds, higher grips and higher vaults?


dj

dj, all I am trying to find is if the people who's speed at the take-off 9.9 m/s will all have the same mid. In my opinion due to differences in run cadence people could have a large difference from a single value in a chart. That is all I am saying.

The question is, are all people who run with the same speed and hold the same grip and clear the same height must have the same mid?

[dj]

Voltuer

I have found it to be true though. Surely you would say Petrov is such an individual. Would you say Bubka already covers what the MID chart would teach him?

Sometimes..yes… and sometimes no.. sometimes even bubka was “offâ€

[charlie]

Dave, Sent you emails but can't get through! Alot of coaches don't buy into the mid because you are dead on and THEY didn't come up with the chart. Had knee surgury tues and am coming after you. Had 8 state champions this season Eli 7th grade #1 in the nation 13'. Guess what , he hits his mid on every jump. You are right again!! hit your mid and set records and stay safe. Have a safe and succesful( thats a given)trip. See you when you get back. CHARLIE(bent arm block) BUBKA

[dj]

hello

check the run again.. do we want to run this way or not!!!???

hope the link comes throught..

dj

if not master could you maybe move it forward.. to here..

this run was created by following the "MID" chart.


For convenience, here is a direct link to the video of Mike Tully dj is referring to.

- master

[master]

Again, for convenience, here is a direct link to the video of Mike Tully dj is referring to.

- master

[dj]

good afternoon

SPORTS SPEED.. George Dintiman/Bob Ward/Tom Tellez

Pages 172-173-174

SPRINTING SPEED:
STRIDE LENGTH X STRIDE FREQUENCY

Sprinting speed is the product of stride length and stride frequency. Maximum speed exists only when these components are in correct proportion. Stride length is best improved by increasing your force against the ground. The resulting reaction from the ground drives the body's center of mass farther forward, lengthening the stride naturally (figure 8.1). When your foot makes contact with the ground, it must be directly under your body's center of gravity (figure 8.2). For example, if your foot lands to far out in front of your body and ahead of your center of gravity when you are sprinting (a condition known as overstriding), it will cause a braking effect resulting in a lose of speed.

Stride frequency is the time required to complete a stride and is limited by the length of the stride. Thus, although stride length is determined when force is applied by pushing against the ground, stride frequency is merely the time required to complete that stride. Again, maximum speed is achieved when stride length and stride frequency are in correct proportion. Forcing a greater stride frequency will only produce a shorter stride length and result in a loss in speed. The emphasis should be on improving stride length naturally, without overstriding , and not on forcing greater stride frequency.

Sprinting involves a series of jumps from one foot to the other; stride is lengthened by increasing the power of the push-off and jumping farther without touching the lead foot down ahead of the center of gravity. Stride length is increased by exerting more force during high-speed movements. This force requires additional strength, power, and flexibility.

What we need to really think about here is that it is the force created by the speed of the leg acceleration driving the ball of the foot into the ground (hammer to the nail effect) that creates the stride length. It is not simply the speed of the movement, or the lift that creates speed, but it is the foot driven to the track that creates the force to create longer strides. The increased speed of the drive movement hitting under the center of gravity accomplishes two things, one is less ground time' the second is a longer stride in the same amount of time in the air and not in ground contact..

Sprinting speed is the product of stride length and stride frequency. Maximum speed exists only when these components are in correct proportion.

The MID chart has proven to have the correct proportions (stride length and stride frequency) for the speed needed for the GRIP associated with that MID.


dj

[dj]

volteur

you are correct..... i went way overboard.. because of frustration..

yes plenty have jumped high without a mark..

rick even stated "why" my chart is right.. but no ones sees that!!?? not even he understands his frequency and lentgh statements of "fact" is whay the chart is correct...

that's my frustation.. and the fact that it could be a very good "tool" for many coaches and athletes.. for saftey, speed, correct technique and accuracy..

i guess it's not just before it's time... but need not have a "time"..

sorry i couldn't explain it well enough....

dj

[baggettpv]

Maybe a different forum but here goes.

So here's the deal.
DJ (and anyone else interested), take the mid mark chart and all other info and scale the run positions of each step on one piece of 11" x 18" graph paper. Use the lowest grip on the top of the sheet and progress the layouts thru a 15' grip on the bottom of the sheet. Keep the plant box on the same vertical line on the left side.
Ok so now we have the data of the run, grip and takeoff in visual form.
*This data shows much information.
*The kids performing at the top probably do not look like the kids on the bottom eh?
*The closer to the bottom the more similar they look like.
* The closer to the top the more different they look.
*The closer to the bottom they are faster
*The closer to the bottom they are better jumpers from a run
*The closer to the bottom they have more efficient technique
etc.....
So we get a kid with an 11' grip and the goal is to get to a 15' grip right?
How do we do it. That is the big question.

Rick Baggett
WSTC LLC

[PVstudent]

The mid mark thread on PVP has generated much recent bubble and froth with a generous helping of bombast, bluff and bluster!

In an effort to get the topic back on course and to tease out the science and physics in DJ's claims in regard to his undoubtedly useful mid mark chart I propose DJ provide his analysis of the approach run data of two National / International standard vaulters (one female and one male) that I supply for open PVP discussion.

Given the multifactorial nature and the complex interactions in pole vaulting I do not believe many of the claims being made concerning the efficacy of this "mid" chart and in particular claims as to the universality of it's practical application. The concept of 'one size fits all' does not ring true to me for a plethora of reasons..

However, I am always willing to suspend disbelief when there is some objective evidence to back up the claims made.

I supply the following data: horizontal speed versus distance, step lengths, step rates, average ground speed per step and in the case of the female vaulter associated changes in the angle of the pole per foot contact and change over the entire approach run.

Specifically I would like DJ and others who understand his chart to address the following questions:

1. Where should the 6 step (out from the takeoff) coaches check mark or the "mid" be set for each vaulter in each case study?

(I believe a 6 step "mid" can only logically be a mid mark for a 12 step approach run hence my preference for the term coaches check mark! It also alludes to the essential purpose of the "mid" check mark as being primarily an aid for the coach to facilitate relatively objective observation based decision making in regard to the structure,rhythm and change of tempo (cadence) of the phases of a particular vaulter's approach run. The feedback conveyed accurately, with appropriate precision and language suited to the individual can then be used by the vaulter with confidence in making run adjustments in training and very importantly competition.)

2. What variability in stride length either side of this 6 step check mark ("mid") is the tolerable limit for each of the vaulters in case study one and two?

The data records of the two vaulters approach runs shows that each vaulter has particular issues with respect to the stride length and the rates used at various phases of the approach hence my third question is as follows.

3. Specifically with respect to the location of the 6 step check ("mid") you identify for each vaulter, what recommendations would you make in regard to improving the structure and tempo of their approach running? On the basis that your recommendations are carried out will the location of the check mark ("mid") change? If so in what direction and by how much?

4. Knowing the height, takeoff distance from the back of the box (the line at the top of the rear wall) and the horizontal speed at takeoff foot touch down (see Charts) where do you recommend the vaulter, in each case, be gripping the pole? (Data were gathered when the female was using a 4.30m pole and the male a 5.20m pole.)

If there is any formula or equation used in objectively constructing (deriving) the mid marks for the vaulters are you willing to put them up for scrutiny?

The data I supply in the case studies clearly indicate the empirical 6 step check or "mid" for each vaulter on their respective jumps. Since I consider both vaulters to have major approach run faults I expect that your "mid" mark will be considerably different to the empirical ones shown!

Finally I am still unconvinced about your claims in regard to stature having no (little) relationship to step (stride length). The Weyand (Harvard)studies don't disregard size scaling effects! The inference regarding stride (step) length you have made from their studies and other sources appear to be questionable.Where is the data to support your position do you have the specific references to the research and or if it it personally collected data could you share it with PVP readers?

DJ, I understand your passion,commitment and concern for safety of pole vaulters and it is in this spirit that I express the hope you will share the math,physics and mechanics data that underlie your "mid" mark chart so that "I, along with others, can get it!" I am an avid student and coach of this event (for many years) and it is my duty of care to the athletes I work with to be as knowledgeable and as safe as I can be in my coaching. I wish to use the tool you provide but I want the assurance of being able to defend it rationally should I be put to the test in any legal action that might arise, should I use it wrongly or in a misguided way!

Given that you publicly claimed to be able to improve any pole vaulter's approach run I eagerly await your responses to the questions and recommendations with specific reference to the two athletes in the case studies.

The following links are to the "full presentation" of the data for each case; first the female athlete, and then the male athlete. Below are two pages, one from each of the pdf files.