Some scientific analysis of Mao's 3A

[SkatingAnalyst]

No, no question. Thank you.

However, we should note that as Blades of Passion said, actual time measurements of Mao's hang time exceeded 0.45, so she might actually be jumping higher than that.

This discussion was interesting because now, I can say with some confidence that if Yuna's hang time is longer, and if Yuna's jump is covering more horizontal distance, then Mao's vertical speed going into her triple axel is probably faster than Yuna's.

If Mao's hang time is shorter, you cannot say her vertical speed is faster.

All you can say is, Mao might rotate faster her 3axel than Yu-Na's 2axel.

By the way... Where do you live? I live in Edison, NJ.
I used to go Hackensack often where Miki trains.
Now I go all the way to Delaware to see my relative practice.

I gotta go to sleep... Nice talking to you... Good Night.

PS. It's been 43 years since I graduate the high school...
I had hard time to figure out the formula together.

 

[hurrah]

If Mao's hang time is shorter, you cannot say her vertical speed is faster.

I said 'probably'. It is not unreasonable to assume this as we can see that Yuna's double-axel travels far more horizontally than Mao's jumps.

Where do I live? Ummmm... I should have a cyber-wise answer ready but don't, and sorry, I'd rather not tell.

Sweet dreams! :agree:

 

[adoreyuna]

1. unexpected / creative / difficult entry
2. clear recognizable steps/free skating movements immediately preceding element
3. varied position in the air / delay in rotation
4. great height and/or distance
5. superior extension on landing / creative exit
6. superior flow in and out (and in-between in jump combinations / sequences)

That is old.

Here is new one.

Updated Guidelines for marking +GOE of Single/Pair Elements
(positive aspects)

Jump Elements

1) unexpected / creative / difficult entry
2) clear recognizable steps/free skating movements immediately preceding element
3) varied position in the air / delay in rotation
4) good height and distance
5) good extension on landing / creative exit
6) good flow from entry to exit including jump combinations / sequences
7) effortless throughout
8) element matched to the musical structure

Well, what about the one I got from http://library.thinkquest.org/15384/physics/index.htm?

You said that:



But you know, our eyes do give us an approximation of the trajectory. I can see that Mao's triple is of approximately equal height to Yuna's double. I can also see that Yuna's double has more horizontal distance compared to Mao's triple. And so, the only factor that we can make no assumption whatsoever within the formula:

Y=VyT+0.5GT^2

Y=vertical height, Vy=initial vertical velocity, T=hang time, G=acceleration due to gravity

is the the speed, i.e., velocity. If we assume that vertical height between Mao's triple and Yuna's double is the same, and if we assume that Yuna's hang time is longer than Mao's, both of which assumptions might be wrong of course, but assuming they are correct, then Mao must have more speed (in the upward direction, that is) going into her jump as compared to Yuna.

Furthermore, if we assume that Yuna's hang time is longer than Mao's and Yuna's jump covers more horizontal distance as our eyes tell us, then, according to the logic of:

X=VxT

X=horizontal distance, Vx=initial horizontal velocity, T=hang time

Yuna must have more horizontal speed across the ice when she does her double as compared to Mao, which would indicate that she is more likely to telegraph her double axel.

Conclusions which can be drawn according to these laws of physics correlates with what I see. I have see Mao's triple popping quickly up into the air. I have seen Yuna telegraphing her double axel.

Y=VyT+0.5GT^2

If that formula were right, skaters can't land on the ice, as time goes by, skaters are just up, up, up.

This one is right.

It is very important that to ideally perform Axel is to throw a body into the air, not reduce but make the best of entry speed, without the delay in the flow of the force on a toe. In this case, owing to no delay, the blade of the axis just little scratch the ice, and there is no resistance of a flow of the body. If skaters brake suddenly to jump an axel causing the blade to skid, even if they can jump high, that technique is not only the easiest way but also the worst, severely forbidden by strict coaches, because it is one of the typical examples of Loss of flow. It reveals naturally their level of jumping technique and skating skills, so it theoretically has a bad effects on them especially in GOE and SS of PCS, but I think it practically depends on skaters.

http://img684.imageshack.us/i/12577603582009110918544.jpg/
This pictures show the ideal axel. It is made from Elements of Basic Skating Video (the fundamentals of Figure Skating by analyzing basic skating techniques) You can buy it. References FS8

A preparation position is also important. The thing is that as skaters are about to jump an Axel, if they bend low like the fetal posture, it has nothing to do with the flexibility and strength of knee and ankle at all but something to do with a unskilled habit. And it is far from effortless throughout which is #7, just looking very rough and poor technique. The crouching take-off pose also makes judges know skaters' bad grades on their jumping technique and skating skills. Hence, it is said that teachers must sternly ban it.

This picture shows one of the best Axel.
http://img706.imageshack.us/i/kuse23a.gif/
You can see Mr. Kulik jumped from Spread eagle to 3A. He didn't brake himself but just threw his boy into the air without bending low to the ice gravely.

 

[hurrah]

I am afraid, I cannot understand the mathematical formulation provided, and probably will not buy the video that you reference, so there is no way I can say yay or nay to what you assert.

However, it surely does seem as if you know alot.

Though, regarding Illia Kulik's triple-axel, I can see that he does bend his knees and ankles deeply, and his take-off blade is not straight but perpendicular to the direction of the jump. I think as other posters have mentioned, it is really impossible to do the triple-axel without some pre-rotation, and the whole idea that you can achieve height without having your knees over your ankles is counter-intuitive.

Can a human body jump in an upward direction without bending one's knees, and can one bend one's knees without bending one's ankles? I'd say it's virtually impossible to jump up without knee and ankle bend, unless you've got jet engines on your soles that will propel you off the ground, like a space jet.

 

[hurrah]

Hey, I got it. You're saying:

X=Vx-gt
Y=Vyt-0.5gtxt

Actually, that makes sense.

While trying to re-read your formula, I came across:

http://www.physicsclassroom.com/mmedia/vectors/mr.cfm

I was under the assumption that Yuna's hang time was longer than Mao's, but if Yuna's jump is wider, maybe Yuna's hang time is actually shorter?

Does anyone know what Yuna's hang time is?

 

[adoreyuna]

I am afraid, I cannot understand the mathematical formulation provided, and probably will not buy the video that you reference, so there is no way I can say yay or nay to what you assert.

However, it surely does seem as if you know alot.

Though, regarding Illia Kulik's triple-axel, I can see that he does bend his knees and ankles deeply, and his take-off blade is not straight but perpendicular to the direction of the jump. I think as other posters have mentioned, it is really impossible to do the triple-axel without some pre-rotation, and the whole idea that you can achieve height without having your knees over your ankles is counter-intuitive.

Can a human body jump in an upward direction without bending one's knees, and can one bend one's knees without bending one's ankles? I'd say it's virtually impossible to jump up without knee and ankle bend, unless you've got jet engines on your soles that will propel you off the ground, like a space jet.

Please read my writing carefully.
More understandable these pictures can help you.

http://img691.imageshack.us/i/80662382.jpg/
http://img682.imageshack.us/i/84477156.jpg/
http://img682.imageshack.us/i/56981917.jpg/
http://img682.imageshack.us/i/36408607.jpg/
http://img691.imageshack.us/i/40505964.jpg/

It is not hard to tell the significant differences among them.

 

[inside edge]

Please read my writing carefully.
More understandable these pictures can help you.

http://img691.imageshack.us/i/80662382.jpg/
http://img682.imageshack.us/i/84477156.jpg/
http://img682.imageshack.us/i/56981917.jpg/
http://img682.imageshack.us/i/36408607.jpg/
http://img691.imageshack.us/i/40505964.jpg/

It is not hard to tell the significant differences among them.

:yes: :yes:

 

[hurrah]

Please read my writing carefully.
More understandable these pictures can help you.

http://img691.imageshack.us/i/80662382.jpg/
http://img682.imageshack.us/i/84477156.jpg/
http://img682.imageshack.us/i/56981917.jpg/
http://img682.imageshack.us/i/36408607.jpg/
http://img691.imageshack.us/i/40505964.jpg/

It is not hard to tell the significant differences among them.

Well, those are photos of one specific moment in different jumps---img691 could be a moment two seconds before the take off, img 682 could be a moment three seconds before the take off, so forth---so they're not meaningfully comparable. But I now see what you are trying to suggest, that because Mao's upper body is lower than the other photos, her technique is not good. Well, if you look at her body position right at the moment when she takes off, it is very upright, so if the argument is that an upright body position at the moment of take off indicates good flow, then she does have good flow into the jump.

Furthermore, when I spoke of deep ankles and knees as being necessary for a good takeoff, I really did mean ankles and knees, not the upper body. So even though the photos you provided are not definitive proofs that any one of them are good/bad jumps, I would say that img682 (84477156.jpg) does capture a moment that shows what I meant by not good technique, as the knees are not over the ankles as much as the other skaters' are. I was saying that the more the knees are over the ankles at the moment of take off, the more spring the skater can induce to jump high into the air.

Not only that, the more the knees are positioned over the ankles, the more control the skater has over his/her balance, which is something I was taught by my Alpine skiing instructor---I know it's a different sport, but even just thinking about how we maintain our balance in daily life, it's common sense. For example, when you ride a train standing up, the way you maintain your balance is to position your knees over your ankles by slightly bending your knees right? A human body will generally maintain balance/control against falling by putting one's knees over the ankle, so more the body is able to position one's knees over (i.e., in front of) the ankle, more balance/control the body will be capable of.

And having the ability to maintain one's knees over one's ankle requires not only flexibility but great strength, particularly when one is trying to do that skating with speed.

 

[sleepymom]

Hey, I got it. You're saying:

X=Vx-gt
Y=Vyt-0.5gtxt

Actually, that makes sense.

While trying to re-read your formula, I came across:

http://www.physicsclassroom.com/mmedia/vectors/mr.cfm
I was under the assumption that Yuna's hang time was longer than Mao's, but if Yuna's jump is wider, maybe Yuna's hang time is actually shorter?

Does anyone know what Yuna's hang time is?

For the distance, again that's nothing to do with Vy. ( It's orthogonal direction ). I know this is long thread, but this has already been explained around page 10 or before.

On the page 10 of this thread, gfskater measured the time of each of their jump during their warm up and Yuna's longer than Mao's.

 

[hurrah]

For the distance, again that's nothing to do with Vy. ( It's orthogonal direction ). I know this is long thread, but this has already been explained around page 10 or before.

On the page 10 of this thread, gfskater measured the time of each of their jump during their warm up and Yuna's longer than Mao's.

So even the amended formula is meaningless? Oh, well, never mind. I give up on the project of trying to compare speed, height, width and hang time of jumps.

So I guess all we can safely assume is that Yuna's hang time is longer and Mao's rotation speed is faster...

 

[Bennett]

A bit off topic, but it's really impressive to see mathmatical formula in FS forums (not at every forum but I do see them at some other ones, too). I wonder if this is specific to FS or something common in other sports forums.
When I was in college, skaters who majored in math and physics wanted to analyze the trace on the ice mathmatically, and some others were really impressed by their intelligence but also found it kind of nerdy as well (Oops). Somehow I happen to be the one who started this thread and it would be cool if the discussion here helps advance the scientific understanding of FS!

 

[adoreyuna]

Well, those are photos of one specific moment in different jumps---img691 could be a moment two seconds before the take off, img 691 could be a moment three seconds before the take off, so forth---so they're not meaningfully comparable. But I now see what you are trying to suggest, that because Mao's upper body is lower than the other photos, her technique is not good. Well, if you look at her body position right at the moment when she takes off, it is very upright, so if the argument is that an upright body position at the moment of take off indicates good flow, then she does have good flow into the jump.

Furthermore, when I spoke of deep ankles and knees as being necessary for a good takeoff, I really did mean ankles and knees, not the upper body. So even though the photos you provided do not provide any definitive proof that any one of them are good/bad jumps, I would say that img682 does capture a moment that shows what I meant by not good technique, as the knees are not over the ankles as much as the other skaters' are. I was saying that the more the knees are over the ankles at the moment of take off, the more spring the skater can induce to jump high into the air.

Not only that, the more the knees are positioned over the ankles, the more control the skater has over one's balance, which is something I was taught by my Alpine skiing instructor---I know it's a different sport, but even just thinking about how we maintain our balance in daily life, it's common sense. For example, when you ride a train standing up, the way you maintain your balance is to position your knees over your ankles by slightly bending your knees right? A human body will generally maintains balance/control against falling by putting one's knees over the ankle, so more the body is able to position one's knees over (i.e., in front of) the ankle, more balance/control the body will be capable of.

And having the ability to maintain one's knees over one's ankle requires great strength, particularly when one is trying to do that skating with speed.

I think you have right to believe that your favorite skater's skill is high quality without any professinal data or evidence. Why not? No problem. It is not important whether it is based on Judges’ Manual Single Skating and Elements of Basic Skating Video or your belief. I think I was meddling your affairs.

Good night.

 

[chloepoco]

I think you have right to believe that your favorite skater's skill is high quality without any professinal data or evidence. Why not? No problem. It is not important whether it is based on Judges’ Manual Single Skating and Elements of Basic Skating Video or your belief. I think I was meddling your affairs.

Good night.

Touchy, much?

 

[miki88]

Seriously, I think this thread should close. It just provides a place for some people to use scientific evidence to show that Mao has bad technique. I mean this argument can be carried out without complicated scientific stuff that just confuse a lot of people.

 

[sk8rdad]

For those who want to understand some of the physics behind jumping perhaps this site will help.

http://btc.montana.edu/olympics/physbio/biomechanics/bio-intro.html

 

[sleepymom]

For those who want to understand some of the physics behind jumping perhaps this site will help.

http://btc.montana.edu/olympics/physbio/biomechanics/bio-intro.html

Thank you, that's wonderful! That's very right-on website to this thread.

 

[sk8rdad]

Thank you, that's wonderful! That's very right-on website to this thread.

You welcome.

 

[adoreyuna]

Touchy, much?

HA HA, I am not that shallow.
I regret a little bit not having just seen someone's belief.

If I may be so bold as to say that it was quite funny that how they could bring in old rules instead of new ones and wrong formula they didn't know well so as to scientifically analyze their favorite skater's technique.

Hence, I said new rules, right formula and something important based on official elements offered by ISU. But what I read was just someone's belief, so I was feeling out of place here and I didn't need to talk about cult, because I am sure that everyone's entitled to their own belief. Am I supposed to be touchy, much ?

 

[hellcat]

Though, regarding Illia Kulik's triple-axel, I can see that he does bend his knees and ankles deeply, and his take-off blade is not straight but perpendicular to the direction of the jump. I think as other posters have mentioned, it is really impossible to do the triple-axel without some pre-rotation, and the whole idea that you can achieve height without having your knees over your ankles is counter-intuitive.

Can a human body jump in an upward direction without bending one's knees, and can one bend one's knees without bending one's ankles? I'd say it's virtually impossible to jump up without knee and ankle bend, unless you've got jet engines on your soles that will propel you off the ground, like a space jet.

Here's better view of Kulik's jump in his younger days:

Kulik 3A

Doesn't he look like frisbee?

 

[hurrah]

Here's better view of Kulik's jump in his younger days:

Kulik 3A

Doesn't he look like frisbee?

Frisbee as in he's goes with great speed at great height and depth? Yeah, it's a great triple-axel. And of course Illia Kulik's triple-axel is better than Mao's.

Are you so desperate to deny Mao's talent, the only woman now skating who successfully completes triple-axels in competition regularly, to the extent that you can't see the silliness of comparing a male skater known for having one of the best triple-axels in the history of figure skating to Mao?

This is really tiresome. I just got interested in this thread because I thought there would be some interesting discussion that could explain why Mao is able to do the triple-axel. (And so thank you sk8rdad for your tip.)

Just look at Mao. She doesn't have the physique nor strength that men have, and yet she's able to do the triple axel. So surely there must be some physical reason, like her ability to rotate or exceptionally ankle/knee durability or something, that can explain how that's possible.

And adoreYuna, you can spend your time quoting some ISU document or showing arbitrary photos to try and appear that you are far more of an authority on figure skating than I am, but the fact of the matter is, Mao is the only woman skater now who gets triple-axels regularly ratified with positive GOEs by ISU judges in competition. However much you may know about figure skating, you can't be more of an authority than the judges.