Thickness of Stepanov's shoe?

[Suso2]

Per:

The 4.8cm advantage makes sense if we look at Stepanov's best with a 13mm sole in 1958, the 2.12 in the dual meet against the Americans in Moscow.
By then the 13mm rule was in effect and the shoe was inspected by the Americans. That was the closest Stepanov ever came to the 2.16 with a regular shoe and by 1959 he was gone.

But please keep in mind that the numbers in my long posting were all fake, I made them up to facilitate my explanations!

I suppose a built up shoe would be impossible with a curved flop run-up. It would have required a slower, minimum curved run which would have been pointless.
Well, maybe Manson at his slow no-curve run stage of a few years ago years ago could have given it a go.

No, I believe it should be perfectly possible to run a curved flop run-up with shoes of different sole thickness. The first floppers probably all used shoes of different thickness, and they did not seem to have very great problems running on a curve.

Suso2, you should definitely post more often.

Haha, the TFN boards are a very fun temptation that I force myself to stay away from as much as possible. You know, I do need to hold a job too.

What about a short analysis of what Silnov is doing with his technique?

All I have is some videos from the Olympics. He is extremely fast, is in a low position in the final part of the run-up, and has very good arm and lead leg actions during the takeoff phase. All this is phenomenally good, and together with his excellent takeoff leg it makes him get a lot of height. But then his bar clearance is not good. He does not seem to be making any bad actions over the bar, and the timing of his arching and un-arching seems very good. But he just does not somersault enough, and he does not arch very much. I think that these two problems are probably linked. The source of the problem is most likely in the run-up or in the takeoff phase. He is terrific at everything related to getting HEIGHT from his takeoff, but he has problems generating the appropriate ROTATION from the ground (the appropriate angular momentum that he needs for the bar clearance).

Without a more complete mechanical analysis, I can't figure out what it is that is messing up his generation of angular momentum during the takeoff phase. Maybe he does not have the appropriate amounts of lean backward and toward the left at the start of the takeoff phase, or maybe he is not rotating forward and toward the right enough between the start of the takeoff phase and the end of the takeoff phase, or maybe his strong arm and lead leg actions, while very good for the generation of lift, are interfering too much with the generation of angular momentum, or maybe he IS doing something wrong in the air, or maybe ... ugh --it's really hard to say! And no, I have not really noticed any of this series of conceivable causes that I have just rattled off.

[Per Andersen]

Hey, thanks Suso2!
That was excellent about Silnov. I thought he maybe started his un-arching a fraction too soon, before his butt had completely cleared.

[bambam1729]

Suso2 - you definitely need to post more often. All of us have jobs too.

[Suso2]

Per:

I just looked again at his 2.34 and 2.36 clearances, and I agree with you. He started his un-arching a little bit too early in both jumps. So that is definitely a technique defect, to be added to his insufficient angular momentum and insufficient arching.

[Suso2]

bambam:

Haha, I assumed that most of you guys (other than the retirees) also did have jobs. My real problem (hmmm, problem? ) is that I have too many other extraneous interests and hobbies on top of my job to be able to afford to increase my dedication to any single one of them, tempting though they all are. (And, thank Zeus, I don't fly Warbirds on Internet anymore!)

[eldrick]

There are two advantages to wearing a thick-soled takeoff shoe and a thin non-takeoff shoe.

Advantage #1. One advantage is the larger vertical range of motion that the center of mass has available during the takeoff phase

can you elaborate on underlined ?

i presume you mean longer arc, but does that necessitate a higher absolute COM as that's what we're interested in

[eldrick]

All of us have jobs too.

i'm going to when i see you ( but i got an exetension on michelle wie because of 1y timeout with wrist )

all my mates went into the saw trade & told me to, but sawing for 5 hours/day didn't seem a particularly intellectual use of a working day

being stuck counselling numerous neurotic young-20-something women who've split with their eminently very sensible boyfriends is even worse !

[Suso2]

eldrick:

I am not sure what you mean by "longer arc", but I assume that you are referring to the curved path followed by the c.m. during the takeoff phase (the section of the green curve between touchdown and takeoff --i.e., between the 1st and the 3rd red dots-- in http://home.comcast.net/~dapena/cmpath.tiff ). By a "larger vertical range of motion", I am referring only to the length of the VERTICAL component of that curved path. It's the "delta-Z" distance marked in http://home.comcast.net/~dapena/cmpath-vertical.tiff .

Within certain limits, a larger vertical range of motion during the takeoff phase allows the athlete to generate a larger amount of vertical velocity. This is analogous to what would happen in a purely vertical throw of an object. See http://home.comcast.net/~dapena/shot.jpg . If you are going to release a thrown object at a certain height, you will be able to give that object a larger final vertical velocity (and therefore also a higher peak height) if you start the throw from a low height (as in image b) than if you start the throw from a higher height (as in image a). Just try throwing any object upward as hard as you can in the two different ways shown in http://home.comcast.net/~dapena/shot.jpg, and it will be evident that, when you start the throw from the lower position the object ends up reaching a higher height at the peak of its flight path. This is because you are using a longer vertical range of motion to accelerate the object, which gives you more time to push upward on the object, which allows you to exert on the object a larger impulse (force multiplied by time), which in turn gives the object a larger final vertical velocity, and ultimately a larger distance of upward travel from the point of release to the peak of the object's flight.

A high jump takeoff has a fair amount of similarity to this situation: A lower position of the c.m. of the jumper at the start of the takeoff phase and/or a higher position at the end of the takeoff phase provide a longer vertical range of motion of the c.m. during the takeoff phase, and therefore a larger vertical velocity at the end of the takeoff. In turn, this will produce a larger vertical distance of travel of the c.m. from its location at the end of the takeoff to its location at the peak of the flight path.

[eldrick]

larger vertical range of motion

thank you

we call it

"larger vertical component"

over here


"range of motion"

is too nebulous for english mores ( as i'm sure you've learnt...)

[mrbowie]

I had one of those legal built up shoes that was made by Adidas in about 1962. In non-scientific terms, I thought it helped stop my forward motion and force me to lift upward better than I would have been able to with a thinner-soled shoe.

I noticed that the faster high jumpers ran at the bar, the more difficult it was to find the strength to plant and leap upwards. when Charlie Dumas jumped, he was able to gain lift easier because he came at the bar so slowly.

To me, the only comparison I can make as to why it feels like jumping with a raised shoe helps lift is that it reminds me of the springboard coaches sometimes use with neophyte jumpers, in that it makes it easier to turn forward motion into upward thrust. It is almost like having a lever on your foot.

[Suso2]

mrbowie:

I had one of those legal built up shoes that was made by Adidas in about 1962. In non-scientific terms, I thought it helped stop my forward motion and force me to lift upward better than I would have been able to with a thinner-soled shoe.

Yes, the built-up shoe will tend to make you lose more horizontal speed during the takeoff phase (nothing wrong in that, as long as the loss is during the takeoff phase and not in the penultimate step of the run-up), and it will also make you get more lift. What you are saying makes perfect sense.

I noticed that the faster high jumpers ran at the bar, the more difficult it was to find the strength to plant and leap upwards. when Charlie Dumas jumped, he was able to gain lift easier because he came at the bar so slowly.

The high jump takeoff is executed differently if you are just jogging slowly into the takeoff and simply trying to pop up into the air on the sheer power of your takeoff leg, than if you are truly trying to use the run-up speed to help you to jump higher. The high jumper needs to get the "feel" for how the takeoff needs to be executed in order to reap the benefit of the faster run-up. Otherwise, a faster run-up is not helpful. Of course, there is also a limit for how fast a given high jumper can go and profit from that speed. If your run-up is too fast, you start getting less lift.

I realize that this explanation was probably not very clear. I'll try again with an example with made up numbers for a hypothetical high jumper. Let's consider a given high jumper who uses a 5.5 m/s run-up. This high jumper may jump worse (less height) if he tries a 6.0 m/s run-up if he does not know how to execute a proper "getting-advantage-out-of-the-run-up" takeoff. But if he learns how to do this, he will then be able to jump higher with a 6.0 m/s run-up, and still better with a 7.0 m/s run-up, and maybe still better with a 7.5 m/s run-up. But if he tries anything faster than a 7.5 m/s run-up, his leg will begin to buckle, and his jumps will get worse. The only way to be able to profit from a faster-than-7.5 m/s run-up will be to get into better physical condition, improve the capability of the takeoff leg. Then, this jumper will be able to jump higher with a 7.7 or 7.8 m./s run-up. But anything faster than 7.8 m/s (for example!) will now make his jumps get worse. To use profitably a faster run-up, he needs a still stronger takeoff leg, etc. What I am saying is that how fast you are supposed to go in your run-up depends to some extent on your knowledge of how to execute the takeoff, and after you get that knowledge, how fast you are supposed to go in your run-up will depend also on how strong your takeoff leg is.

Dumas probably never learned how to make proper use of the run-up to get lift into his jump. In his day (1956), it was not widely known yet that a faster run-up than what he was using, together with a modified execution of the takeoff phase would have led him to still higher jumps. You can't really blame Dumas nor his coach for this, it was the "state of the art" of high jumping technique at that time --although Brumel's future coach, Dyatchkov, was already figuring out that a faster run-up was better. Mind you, there were some high jumpers who had used fast run-ups way before 1956. A great example were the Japanese jumpers from the 1936 Olympics, who look really fast in the Leni Riefenstahl Olympic film. But in 1956 there was still wide disagreement about whether a faster run-up really helped at all.

To me, the only comparison I can make as to why it feels like jumping with a raised shoe helps lift is that it reminds me of the springboard coaches sometimes use with neophyte jumpers, in that it makes it easier to turn forward motion into upward thrust. It is almost like having a lever on your foot.

mrbowie, another excellent statement. You are right on the money. The springboard plays exactly the same role as a very built-up shoe. It's almost as if the build-up is waiting for you at the takeoff point, you don't have to wear it in your shoe. But don't think that neophyte jumpers are the only ones who use this springboard. Some of the top jumpers in the world use it as part of their training and conditioning program.

[Per Andersen]

The Swedish dive straddlers of the early to mid 50's also had understood the value of strength training combined with a longer, faster run-up.

According to Ken Doherty, Les Steers was able to take a huge amount of jumping in practice and thus developed strength. Steers also used a faster run-up than the US straddlers that followed him.
I suppose Dumas took the run-up to the slowest level possible.

[decathlete73]

Hj shoe build up.

Thanks everyone for comments. Suso2
you are the best on info.
I jumped both straddle and flop in decathlons had steps on both sides. I felt more in control with straddle than flop. I had a Adidas high jump shoe with 1/2" build up it was great.

[dukehjsteve]

Re: Hj shoe build up.

Thanks everyone for comments. Suso2
you are the best on info.
I jumped both straddle and flop in decathlons had steps on both sides. I felt more in control with straddle than flop. I had a Adidas high jump shoe with 1/2" build up it was great.

It probably was exactly 13 cm buildup, as that was the limit. I had an Adidas pair just like that in 64-65. In my case, build up was on my right shoe.