Jamaica Invitational , May 4th [Gay 9.86 WL]


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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby toyracer » Wed May 08, 2013 11:19 am

bignate88 wrote: 9.69 represents an average speed: It still doesnt indicate who has more top end speed. Plus those two races were run completely different from each other
If you were to find 10m splits for Blake's and Gay's 9.69 and compare them, that would suffice. Otherwise, it's speculation


Exactly. I was hoping that splits would be produced to support the claim.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby 26mi235 » Wed May 08, 2013 11:50 am

The speed of light is measured down to the centimeter (and maybe beyond). What this means is the time can be measured extremely accurately (10^-10 seconds; i.e., 0.0000000001). Yet, in our splits we cannot get really good measures of speed because we are limited to increments of 0.01, is which is very grainy for this type of assessment. The difficulty is with the placement of the body that is relevant. For this discussion of top speed, the relevant element is the center of mass (and speed here is really velocity, because we are concerned with the vector down the track, not in any other direction).

So, you have to have the right timing equipment, the right location, the right point on each of the bodies at some (e.g. 10m) systematic intervals that can deal with bodies blocking each other. This is a costly undertaking when it does not provide information relevant to the race, per se.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby nicest person ever » Wed May 08, 2013 4:02 pm

26mi235 wrote:The speed of light is measured down to the centimeter (and maybe beyond). What this means is the time can be measured extremely accurately (10^-10 seconds; i.e., 0.0000000001). Yet, in our splits we cannot get really good measures of speed because we are limited to increments of 0.01, is which is very grainy for this type of assessment. The difficulty is with the placement of the body that is relevant. For this discussion of top speed, the relevant element is the center of mass (and speed here is really velocity, because we are concerned with the vector down the track, not in any other direction).

So, you have to have the right timing equipment, the right location, the right point on each of the bodies at some (e.g. 10m) systematic intervals that can deal with bodies blocking each other. This is a costly undertaking when it does not provide information relevant to the race, per se.


Couldn't they just set up some speed guns on the other end of the track (like, at the edge of the stands of the curve but pointed straight down the 100m straight, 1 gun in each lane, pointed at the front of the waist of each sprinter (rather than the upper chest where the bobbing motion might interfere etc), and just measure their speeds as the sprinters are sprinting straight at the guns the whole way, so you could get a continuous reading, updated say, every 10,000th of a second if you wanted, and could just graph the avg mph on an xy plot with x being time in seconds and y being mph. This would probably be a more accurate method than setting up the tripwire style timers at 10m intervals along the track. I wonder if anyone has ever tried this method.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby 26mi235 » Wed May 08, 2013 4:10 pm

I do not think that speed guns are that accurate, although if they took repeated measurements every fraction of a second it might have useful information (or there may be correlated errors specific to each device).
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby nicest person ever » Wed May 08, 2013 4:15 pm

26mi235 wrote:I do not think that speed guns are that accurate, although if they took repeated measurements every fraction of a second it might have useful information (or there may be correlated errors specific to each device).


Yea I was gonna say the same thing. But, I'm not completely sure, but I think recently in the past few years they have invented some new type or speedguns that work differently from the older traditional version that have been around for decades that are much much much more accurate, like, to the thousandth of an mph, instead of to the nearest mph. Obviously one that was only accurate to the nearest whole integer mph value would be utterly useless for our purposes, but if there is indeed some newer kind (which works with lasers if I remember correctly), that is accurate to the hundredth or thousandth of an mph, that would be extremely useful. Just stand the guns on some tripods like 20m past the end of each finish line pointed perfectly straight down each lane and just take a continuous measurement of their speed as they come flying fown the track straight towards the guns, and viola, then we would get to put an end to our guesses as to which people actually truly have the highest top speeds when they run the 100m dash, as well as how fast they reach their top speed, and how much and how quickly they decelerate from said top speed, to a much more accurate degree than using mere 10m splits, by comparison. It would be pretty fuckin awesome. My palms are getting a little sweaty just thinking about it lol
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby 26mi235 » Wed May 08, 2013 7:35 pm

But what is moving - the arm, the leg, the head. You need the center of mass, and this is not a point reflecting the beam -- not quite like a baseball or car.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby nicest person ever » Wed May 08, 2013 8:44 pm

26mi235 wrote:But what is moving - the arm, the leg, the head. You need the center of mass, and this is not a point reflecting the beam -- not quite like a baseball or car.


Well, with the older ones you'd be right, that would be a problem. But for the recent advanced laser ones (not sure these actually exist, but I vaguely think I remember reading about them, I could be way off tho), I think they are a "point" type of thing that you shoot at a tiny point, not a wide beam that takes in a whole blob shaped amount of stuff, coming towards it. Thus, you could just aim the tiny laser point at their belly button, basically. Even so, I guess a big problem would be that the runners don't actually run in a perfectly straight line, but often veer around in their lane from one side of the lane to the other etc, rather than staying dead center in their lane, so even if you aimed a tiny-point right on their belly button center mass, if they slowly veered off to the left or right as they ran, it might be pointed right at their arm or not even be on them at all by the time they are halfway through the race if they've moved sideways enough during the race. So that would be a problem. So, I guess they'd have to bust out these badboys only specifically for very major meets like World Championships and Olympics and stuff like that, where it is realistic to have an individual staff member manning each gun (one for each lane), keeping it pointed at center mass (having it be on a swivel-able tripod sort of like a camera on a tripod), keeping that laser dot on their belly button the whole way through the race as the runners run straight at them, and if the runners sway off to either side of their lane, then just turn it ever so slightly of a miniscule fraction of a degree to the left or right to keep it on their belly button (yes, technically this would make the reading ever so slightly inaccurated once they weren't running straight at the thing and instead a hundredth of a degree off to the left or right, but, it would still probably read accurate to like a thousandth of an mph, instead of a 10,000th of an mph or something, which would still be plenty good enough, especially compared to something like 10m splits by comparison.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby lonewolf » Wed May 08, 2013 9:00 pm

The devil is in the details but that would be an interesting experiment.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby 26mi235 » Wed May 08, 2013 9:12 pm

Several things. It is only the velocity vector down the track that matters; the issue of getting different points on the torso (several inches to the left or right will give you slight variations in measured position, but as long as arms/hands do not get in the way it might not matter.

If you look at a runner the torso surges a bit with each stride. This is a combination of the end of the force being applied forward and the more constant resisting force of air resistance. However, there is also the fact that the body goes up and down a non-trivial amount and when it goes up there is an increase in potential energy and a decrease in kinetic energy. This second cycle will over lap the first one, leading to more variation in speed. Also, the torso/center of mass changes a bit as the legs and arms move forward and back, although I am not sure how big an effect that is.

There are probably statistical techniques that could be brought to bear that would integrate across a number of measurements across the stride cycle that would cancel the variations. There are some other statistical options as well, but I am not familiar with them to an extent necessary to think on my feet in this post.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby nicest person ever » Wed May 08, 2013 9:44 pm

Yea, for one of Bolt's 100m WR runs, I don't remember if it was the Beijing one or the Berlin one, they had a super in-depth velocity analysis where there was an xy graph (y-axis was mph, x-axis was meters of distance down the track from the starting line), and it had this squiggly line, where if you viewed the graph at full size, you could actually see each and every stride he took for the whole entire race. Like, it showed his mph increase and decrease by something like 1 mph up and then 1 mph down for each stride, so it was sort of an overall hill-shaped graph, but the line that the hill was made of was made of a very consistent chain of roughly equal sized tiny squiggles, where each squiggle was his body rocking back and forth per each stride. I'm not sure how they did this, maybe using some ultra-accurate GPS type of thing or something, I dunno, but it was pretty cool. His absolute peak velocity (at the peak of one of the tops of one of the squiggles at around the 60m mark was something like 29.5mph lol. It was beyond sick.

That said, as for your question regarding averaging out/cancelling out the peaks and troughs of these 40-some squiggles to get the overall center body speed, stride-squiggling aside, you can obviously just pass a smooth line through the middle of these squiggles, horizontally like, where it cuts these tiny squiggle-hills (which are what, when combined all together, the main overall hill of the whole graph is made up of) in half, so there is sort of a smooth hill shaped curve line that is basically identical to the shape of the graph, except, middling the peaks and bottoms of the 40-some squiggles that make up the overall arch of the graph, if you see what I'm saying. That line is what represents his overall running speed, correcting for the individual stride ebbs and flows of his running.

This would be so much easier if I could just draw it and post the drawing of one I'm trying to say on here. Bleh. Maybe when I'm less sleepy/more sober I'll try to find the actual graph I'm referring to, or if I can't find it I'll just manually draw an example of what it looked like in mspaint and post the mspaint jpg on here. I just smoked a bowl of weed though and want to chill out and watch some nature programs on tv though, so now's not the best time lol.
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Re: tyson top end to yohans top end

Postby olorin » Wed May 08, 2013 11:21 pm

Grasshopper wrote:
bignate88 wrote:You still haven't given any solid proof. As was stated earlier, if we can get some 10m splits on the FASTEST runs of Gay and Blake and compare, that could very well show who has more top end. For example, IAAF's biomechanical analysis of Berlin 100m final showed that Bolt and Gay hits speeds of over 44kph, Bolt recording the faster of the two.

But you're right, let's not give out medals prematurely. We'll see how the season unfolds

Here's some links to sites with data on the splits for many championship 100m races:
http://berlin.iaaf.org/mm/Document/Development/Research/05/30/83/20090817081546_httppostedfile_wch09_m100_final_13529.pdf
http://myweb.lmu.edu/jmureika/track/splits/splits.html
http://www.sportsscientists.com/2008/08/beijing-2008-men-100m-race-analysis.html
- In Bolt's 9.69 race in Beijing, his fastest 10m split was .82 and his fastest 20m split was 1.64.
- In Bolt's 9.58 race in Berlin there were no 10m splits taken, but his fastest 20m split was 1.61 (.805 avg).
- In Gay's 9.71 race in Berlin there were no 10m splits take, but his fastest 20m split was 1.63 (.815 avg).
- In Carl Lewis' 9.86 race in Tokyo his fastest 10m split was .83 and his fastest 20m split was 1.67 (.835 avg).
- In Maurice Greene's 9.80 race in Seville his fastest 10m split was "only" .84 and his fastest 20m split was "only" 1.69 (.845 avg).
I'm not aware of any splits available for Blake's fastest races. It is possible, though, that someone can run a faster overall 100m time with an inferior top-speed if their acceleration and/or speed-endurance are superior (as in Greene's 9.80 race in Seville versus Lewis' 9.86 race in Tokyo).

Another example that the "top speed" do not play crucial role in the 100:
Johnson and Lewis had the same top speed in Seoul (0.83 for 10m). Both of them reached the top speed between the 60m-70m. Yet Johnson won the race by 0.13 (as he was leading by 0.15 in the 60m mark).
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby shivfan » Thu May 09, 2013 1:36 am

"Behind the warm and respectful applause for Tyson Gay at last Saturday's Jamaica Invitational, there was tangible concern. The quiet American sprinter placed himself squarely in the World Championships sprint picture with a 9.86-second dash over 100 metres. When it was over, he was surrounded by fans with gadgets of various configurations for a photo session befitting a superstar. It was typical Gay - slow start, fast finish. The 9.86 is the fourth-fastest 100-metre run in the 10-year history of the Invitational. Only Asafa Powell, 9.84 in 2005, and Usain Bolt, 9.76 in 2008 and 9.82 last year, are ahead of the Kentucky native in meet history. If you are still worried about the injuries that have slowed Bolt, Powell and Yohan Blake in 2013, here's another tidbit to ponder. Powell's 9.84 stroll was the start of a world-record chase that crested at 9.77 seconds in June. The tall man's monumental run of 9.76 was followed by world records in New York - 9.72 in a race where Gay was second and in the Olympic final at 9.69. Bolt has moved the world record to 9.58 seconds since then, so there's no assurance that Gay - or anyone - will get close anytime soon. It is clear, however, that the American is on his way to a fine season. That puts him on collision course with Jamaica."

http://jamaica-gleaner.com/gleaner/2013 ... orts3.html
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Re: tyson top end to yohans top end

Postby bignate88 » Thu May 09, 2013 6:19 am

olorin wrote:
Grasshopper wrote:
bignate88 wrote:You still haven't given any solid proof. As was stated earlier, if we can get some 10m splits on the FASTEST runs of Gay and Blake and compare, that could very well show who has more top end. For example, IAAF's biomechanical analysis of Berlin 100m final showed that Bolt and Gay hits speeds of over 44kph, Bolt recording the faster of the two.

But you're right, let's not give out medals prematurely. We'll see how the season unfolds

Here's some links to sites with data on the splits for many championship 100m races:
http://berlin.iaaf.org/mm/Document/Development/Research/05/30/83/20090817081546_httppostedfile_wch09_m100_final_13529.pdf
http://myweb.lmu.edu/jmureika/track/splits/splits.html
http://www.sportsscientists.com/2008/08/beijing-2008-men-100m-race-analysis.html
- In Bolt's 9.69 race in Beijing, his fastest 10m split was .82 and his fastest 20m split was 1.64.
- In Bolt's 9.58 race in Berlin there were no 10m splits taken, but his fastest 20m split was 1.61 (.805 avg).
- In Gay's 9.71 race in Berlin there were no 10m splits take, but his fastest 20m split was 1.63 (.815 avg).
- In Carl Lewis' 9.86 race in Tokyo his fastest 10m split was .83 and his fastest 20m split was 1.67 (.835 avg).
- In Maurice Greene's 9.80 race in Seville his fastest 10m split was "only" .84 and his fastest 20m split was "only" 1.69 (.845 avg).
I'm not aware of any splits available for Blake's fastest races. It is possible, though, that someone can run a faster overall 100m time with an inferior top-speed if their acceleration and/or speed-endurance are superior (as in Greene's 9.80 race in Seville versus Lewis' 9.86 race in Tokyo).

Another example that the "top speed" do not play crucial role in the 100:
Johnson and Lewis had the same top speed in Seoul (0.83 for 10m). Both of them reached the top speed between the 60m-70m. Yet Johnson won the race by 0.13 (as he was leading by 0.15 in the 60m mark).

Top end speed didn't play a crucial role, in THIS example.
Let's say Lewis had a world of a better start/first 40 in Seoul, and was within striking distance of Johnson. Top end speed would then be very crucial. You have to apply it to the context of the race rather than weigh it by itself.
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Re: tyson top end to yohans top end

Postby JRM » Thu May 09, 2013 9:13 am

olorin wrote:Another example that the "top speed" do not play crucial role in the 100:
Johnson and Lewis had the same top speed in Seoul (0.83 for 10m). Both of them reached the top speed between the 60m-70m. Yet Johnson won the race by 0.13 (as he was leading by 0.15 in the 60m mark).


Correct. Two sprinters with the same top-end speed will simply remain the same distance apart during the race. What matters is the acceleration. The sprinter who gets out with a greater acceleration (and has a smaller deceleration) will trump the other one.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby 26mi235 » Thu May 09, 2013 9:54 am

Well, there is that deceleration bit too; AP is one who suffers more than his opponents in that phase. It begins in the latter part of the race, but is it at 70m or 90 an dis it rapid once it begins.
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby tm71 » Thu May 09, 2013 8:47 pm

shivfan thanks for the article. seems that the author, a jamaican, was fairly unbiased in his assessment of the situation (unlike other posters on this board).
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby shivfan » Thu May 09, 2013 10:47 pm

tm71 wrote:shivfan thanks for the article. seems that the author, a jamaican, was fairly unbiased in his assessment of the situation (unlike other posters on this board).

I have always felt that Hubert Lawrence is an excellent analyst, and a very nice guy too...no airs.

He is often that soft-spoken guy who gives analysis when Jamaican TV stations cover events such as Champs, Olympics, World Athletics Champs, etc. I always listen to what he has to say....
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Re: Jamaica Invitational , May 4th [Gay 9.86 WL]

Postby Weights&Shoes » Thu May 09, 2013 10:48 pm

tm71 wrote:shivfan thanks for the article. seems that the author, a jamaican, was fairly unbiased in his assessment of the situation (unlike other posters on this board).


Pretty much and I'm also of Jamaican background, but the things I read on here....disgusting at times. Glad to see Tyson feeling completely 100%.
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