Random Figure Skating Questions

apgold said:

So someone can be a senior level skater in their own country but b/c of age restrictions be junior on the international level.

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Yup.

Or they may compete senior domestically and junior internationally even at age 15-18 when they're eligible for both, because they or their federation believes it makes more sense for them strategically to do junior than senior internationals.

I know that the Olympics has age requirements as well.

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The age restrictions for the Olympics are the same as for ISU senior championships. (15 as of the previous July 1)

As a spin off of the age questions.

Why was USFSA able to send Ashley Wagner to Junior Worlds after she had already been to Senior Worlds? I thought once you go up you can't go back?

StitchMonkey said:

As a spin off of the age questions.

Why was USFSA able to send Ashley Wagner to Junior Worlds after she had already been to Senior Worlds? I thought once you go up you can't go back?

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That rule was not in place back then, can't remember when it was implemented. I know it was after the 2011-2012 season cause Denis Ten was at both junior and senior worlds.

Mrs. P said:

That rule was not in place back then, can't remember when it was implemented. I know it was after the 2011-2012 season cause Denis Ten was at both junior and senior worlds.

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Yesh. . . nice double dipping.

So could (not saying should. . . please don't go there in this case I just want to understand) the USA still have sent Polina to junior worlds rather than the Olympics this year? When did her switch occur so to speak?

StitchMonkey said:

Yesh. . . nice double dipping.

So could (not saying should. . . please don't go there in this case I just want to understand) the USA still have sent Polina to junior worlds rather than the Olympics this year? When did her switch occur so to speak?

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Actually, I think the new rule is probably in effect THIS Season for the first time. Because I just remembered that Elena Radionova competed at the junior worlds after doing Senior GP.

I think there was a different rule in place where pairs/dance could not double dip. I think Sui/Han and Takahashi/Tran were the last to double dip in the 2010-2011 season.

In any case, yes Polina could have gone to Jr. Worlds either way because the Olympics was her first senior competition. IF she went to the Olympics, then she couldn't go back to do Jr. Worlds, but again I don't think the rule was in place yet.

lefeury said:

hey all, This is probably a stupider question than most so forgive me, however, I can't seem to add a profile pic to my profile. Any directions would be great.

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http://www.goldenskate.com/forum/showthread.php?19257-Avatar-FAQ-(Updated-Feb-11-2010)


Since you have 25 posts, you can get an avatar. Directions are in the above thread.

You can upload a custom avatar after you have made 100 posts. Directions are also in the above thread.

If you continue to have problems getting an avatar, please tell us about them by making a post in the above linked thread, and we'll work on the problem.

Just wondering if tech experts know how fast skaters go when they are preparing for a jumps? When Yuna goes into her 3/3 she looks so fast I am just curious if anyone has a general idea of the speed skaters reach when they are going into a jump?

Thanks

I guess there are instruments that could measure speed, but I haven't ever heard of it being done. Something like a "radar gun".

What is the highest skating skills score ever given to a singles skater and who was the recipient of that score?

KwanIsALegend said:

Just wondering if tech experts know how fast skaters go when they are preparing for a jumps? When Yuna goes into her 3/3 she looks so fast I am just curious if anyone has a general idea of the speed skaters reach when they are going into a jump?

Thanks

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ETA, 20 mph -- a much higher speed than in my original post below -- was cited by Montana State University in 1998 for a quad jump.

My original post:

Icey said:

What is the highest skating skills score ever given to a singles skater and who was the recipient of that score?

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Patrick has gotten 9.43 at the Olympics for SS while Yuzuru Hanyu got 9.36. Carolina Kostner got 9.29 for her FS at WC 2014, next Yuna Kim and Carolina Kostner got 9.21 for good performances. Not sure if these are the highest of all time but they're probably up there.

KwanIsALegend said:

Just wondering if tech experts know how fast skaters go when they are preparing for a jumps? When Yuna goes into her 3/3 she looks so fast I am just curious if anyone has a general idea of the speed skaters reach when they are going into a jump?

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I'm not a tech expert but from looking at fancam videos, for the 2014 Sochi Olympics free skate, during her entrance glide to her 3Lz combo (while she was still on her left inside edge, where her body position was relatively static), Yuna traveled about 8 feet in a third of a second, which works out to about 16.4 miles per hour. For the lutz itself, she traveled a bit less than 9.3 feet in about 0.6 seconds (from right toe pick on takeoff to right toe pick on landing), which works out to about 10.5 miles per hour of horizontal travel while she was in the air. Haven't worked it out for other skaters yet.

Haven't worked it out for other skaters yet.

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Do it !!!

How do you measure the distance traveled by watching a video?

If the camera's viewing angle is perpendicular to the skater's path, it's fairly easy, provided you know the rink's dimensions, and the distance between the hockey features on the ice (center, offside lines, icing lines, faceoff circles). Your estimate becomes less accurate if you have to adjust for cameta angle.

Vanshilar said:

I'm not a tech expert but from looking at fancam videos, for the 2014 Sochi Olympics free skate, during her entrance glide to her 3Lz combo (while she was still on her left inside edge, where her body position was relatively static), Yuna traveled about 8 feet in a third of a second, which works out to about 16.4 miles per hour. For the lutz itself, she traveled a bit less than 9.3 feet in about 0.6 seconds (from right toe pick on takeoff to right toe pick on landing), which works out to about 10.5 miles per hour of horizontal travel while she was in the air. Haven't worked it out for other skaters yet.

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gkelly said:

How do you measure the distance traveled by watching a video?

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dorispulaski said:

If the camera's viewing angle is perpendicular to the skater's path, it's fairly easy, provided you know the rink's dimensions, and the distance between the hockey features on the ice (center, offside lines, icing lines, faceoff circles). Your estimate becomes less accurate if you have to adjust for cameta angle.

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In the case of Vanshilar's estimates, the Sochi ice did not have any hockey landmarks, did it??? :think:

At Sochi, you would be stuck with knowing the dimensions of an Olympic rink and scaling from there. AFAIR, they took the hockey glass down? so you couldn't use the space between glass sections. Doable, but not very accurate.

Sam-Skwantch said:

Do it !!!

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The issue is that it takes a fair amount of time, since although the math is worked out, the actual measurements are done by my eyeballs. The issue isn't with the math (which is already worked out and I've already wrote up an Excel file that takes the pixel measurement inputs and automatically converts them into rink coordinates), but with determining where the different rink locations (rink edges, skater blades) are in the image. It would be faster (and more accurate) if I wrote up an edge detection algorithm, but that in itself takes time. I was going to do it for the Olympics discussions but they've since closed those threads down so it's not as high of a priority for me anymore.

Also, it depends on what fancam videos (and of what quality) I'm able to find. So far I've only found them for Yuna, Adelina, Carolina, and Yulia. So those are the only ones I'm able to do a full analysis of each jump. The rest, I may be able to analyze them via an alternate method, but it would only be for several specific jumps (the ones that had a replay or a different feed from a different camera angle).

gkelly said:

How do you measure the distance traveled by watching a video?

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I've given an outline of it elsewhere, but basically, fancam videos tend to lack zoom so they cover the entire rink (or at least, parts of all 4 walls). I assume that the rink used at the Olympics was an Olympics-sized (heh) rink of 30 meters by 60 meters. I also assume that the walls around the rink are of the same height and vertical (with obvious exceptions to make space for cameras, etc.). The rest is perspective geometry. If the tops of the walls are in the image, then it's basically just a matter of "lowering" that 30 m x 60 m plane down to the level of the rink (and at least 2 sides of the rink will always be available to do this, if the walls are visible), and then determining the location of the skater's blades relative to the rink. This method isn't (easily) doable with the network feeds because they're zoomed in on the skater -- hence the use of fancams.

dorispulaski said:

If the camera's viewing angle is perpendicular to the skater's path, it's fairly easy, provided you know the rink's dimensions, and the distance between the hockey features on the ice (center, offside lines, icing lines, faceoff circles). Your estimate becomes less accurate if you have to adjust for cameta angle.

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The problem is that the camera's viewing angle is practically never perpendicular to the skater's path, while it will almost always look as if the skater is skating perpendicular to the camera, due to foreshortening (and camera zoom): that distances along the line of sight appear short or "flattened" compared with distances across the line of sight. Failure to take this into account is the main reason why pretty much all of the post-Olympic analysis of jump under-rotations etc. are bogus, including some of the most controversial/heavily discussed jumps. (The other main reason is not estimating blade angle relative to camera properly.) By using a video that can see the entire rink, however, the skater's direct x-y coordinates within the rink can be estimated. Generally it's within tens of centimeters (the size of an image pixel), depending on the resolution of the fancam camera, which is decent considering the camera is usually just an ordinary camera filming from probably nearly a hundred meters away. (It's also worthwhile to note that for most purposes what's important is the relative error between skater boot locations, such as measuring the distance of jumps, which in this case can be smaller than the error in determining the coordinates of the rink in the image.)

Additionally, there was a center line on the rink that was visible in some videos, which splits the rink in half, and can also be used as a basis to determine locations (in this case, the rink itself is used directly, rather than the tops of the walls).

Interestingly, the cameras used for the network feeds are visible in some of the fancam videos, so the network camera's x-y coordinates can themselves be estimated. In other words, the skater's x-y coordinates and the network camera's x-y coordinates can be determined from a fancam video. This means that the camera angle of the network camera relative to the skater's line of travel can be determined fairly accurately and thus accounted for. By accounting for this, then, whether or not a skater did under-rotate a jump (or by how much) can be determined fairly accurately, depending on the camera video quality (how blurry the skates are). With few exceptions, when people looked only at the network feed and didn't take this camera angle relative to the skater's line of travel into account, under-rotations were either exaggerated or diminished depending on whether the skater was moving towards or away from the camera. Hence a lot of the "evidence" for them was flat-out wrong -- or, at best, significantly inaccurate.

An alternate method is to note that the locations of the patterns on the rink walls can also be determined (an example of this is here: http://4.bp.blogspot.com/-QsIslU1dHmA/UvbpNzTHF6I/AAAAAAAACco/_-V2u0qXYug/s1600/DSC_0154.JPG ). With the network cameras' x-y coordinates determined, if there are two different camera shots of the same jump or move, the skater's position (and hence camera's angle relative to skater's line of travel) can be triangulated. This is less preferable compared with the fancam method but it's doable, and is the method I use for if the fancam isn't available. But I can only do it if I have multiple camera feeds, which means having videos from different sources and/or if the replay was from a different angle.

I haven't worked on this much lately because the Olympic-related threads are closed so there's no particular venue to put analysis of them now, plus nowadays I'm working more on school stuff (i.e. dissertation-related research) rather than on this. The principles and math are worked out, it's mostly just a matter of actually manually measuring skater locations for a bunch of different jumps and skaters and writing up the process (and results). That takes a long time to do -- which is why I mentioned this was a long-term project. Maybe by next year's Worlds or something. But a number of measurements were already worked out so it was relatively easy to use them to answer this question (speed of skater).

The issue is that it takes a fair amount of time, since although the match is worked out, the actual measurements are done by my eyeballs

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I'm not trying to make demands and was just joking around. I really appreciate your efforts and I do think people would be fascinated by you results. Thank you so much

That is crazy that they go so fast, but at the same time it must be a thrill for them ( maybe not so much during a competition). I would love to know what that feels like to glide along so fast on the ice.
Thank you for the links and the research. I appreciate it. I bet some men have reached 25 mph, craziness!!