Question about 200 meter straight


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Re: Question about 200 meter straight

Postby user4 » Wed Nov 14, 2012 9:03 am

DJG wrote:[
Now if Bolt drew lane 1 and Blake drew lane 4,5,or 6 would that affect the outcome of the race?
I would say no, it would make it closer but Bolt would still win. Would Bolt time's be slower?
I wouldn't bet the farm on it. His splits would be a little different, I believe, but he would still
run 200 m very fast. All lanes are equal. That's the only approach an athlete or a coach can take.
I don't see lane-draws guaranteeing anything.
FTR: I believe lanes should be assigned by place and then time from the semi-finals. No draws after the first round, period. You want lane 4 or 5, earned it. Or let the qualifiers pick their lane
in the order they qualify: Bolt wins his semi with the fastest 1st place time, let him pick which lane he prefers. That would be fine with me.


That is a fine solution. As gh said, lanes matter allot and letting the accomplishments of the athlete instead of the draw of a straw would be a solution, and one that has been advocated on this forum before.
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Re: Question about 200 meter straight

Postby JRM » Wed Nov 14, 2012 11:03 am

DJG wrote:
gh wrote:"all lanes are equal" may be a great motivational speech to give to your athletes, but unfortunately it defies the laws of physics.


Fortunately, the laws of physics apply to all lanes and the tracks these big-name athletes are running on are the best-designed and best-engineered tracks that money can buy. So I am glad I have never witnessed the scene you describe. I might say "teach your athlete how to run the curve better!"


All lanes are equal still works for me. Even lane 1 in which hardly any sprinter has to run.


Centripetal force is F = mv^2/R, where v is the athlete's velocity and R is the lane radius. The sprinters have to overcome this force to stay in the lane, which takes away from their forward propulsion. So, as GH says, the laws of physics necessitate that all lanes are not equal. Inner lanes (small R) makes for a bigger force. Faster turn running (bigger v) also makes for a larger F. Combine the two and you have an unfair disadvantage to athletes in the innermost lanes.
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Re: Question about 200 meter straight

Postby Olli » Wed Nov 14, 2012 11:31 am

This discussion reminds me of Akii-bua, who ran WR in lane 1. He must have been really great. Or is it different for hurdles?
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Re: Question about 200 meter straight

Postby gh » Wed Nov 14, 2012 11:37 am

Angelo Taylor also won Oly gold out of lane 1.

Physics was a class I dropped out of, but as JRM's equation shows (I think!), if v gets smaller, then F gets smaller, so the effect is less.

If they still ran the 200 hurdles, I daresay there's no way anybody could ever set a WR out of lane 1.
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Re: Question about 200 meter straight

Postby JRM » Wed Nov 14, 2012 12:31 pm

gh wrote:Physics was a class I dropped out of, but as JRM's equation shows (I think!), if v gets smaller, then F gets smaller, so the effect is less.


It not only gets smaller, but it gets MUCH smaller because the force is a function of v^2, and not just v. So, a drop in velocity from 10m/s to 7m/s results in a 50% reduction in force.
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Re: Question about 200 meter straight

Postby gh » Wed Nov 14, 2012 2:10 pm

thanks for clarifying why I dropped out of Physics. :mrgreen:
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Re: Question about 200 meter straight

Postby user4 » Wed Nov 14, 2012 3:55 pm

JRM wrote:
gh wrote:Physics was a class I dropped out of, but as JRM's equation shows (I think!), if v gets smaller, then F gets smaller, so the effect is less.


It not only gets smaller, but it gets MUCH smaller because the force is a function of v^2, and not just v. So, a drop in velocity from 10m/s to 7m/s results in a 50% reduction in force.


a somewhat analogous example from football; a fairly smallish RBs reaching full speed and blasting through the tackles of very large LBers. That ~v^2 thing works, in the case of faster RBs as a plus, in the case of running a tight curve a definite minus.
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Re: Question about 200 meter straight

Postby 26mi235 » Wed Nov 14, 2012 5:47 pm

JRM wrote:
gh wrote:Physics was a class I dropped out of, but as JRM's equation shows (I think!), if v gets smaller, then F gets smaller, so the effect is less.


It not only gets smaller, but it gets MUCH smaller because the force is a function of v^2, and not just v. So, a drop in velocity from 10m/s to 7m/s results in a 50% reduction in force.


Which explains why the effects are bigger for 200s than 400s and bigger for 400s than for 400h's. Also, less for women than for men. One slightly compensating factor, and the compensation is not full -- the force is greater on the inside, but if you run less inside, there is compensation. However, for staggered starts on the turn, you do not get that effect. It is the case that in the 200, the initial speed is lower, so it does not matter as much from 0 to 10 and 10 to 20 as it does for latter. It might be why some guys come hard on the straight -- so they do not have to waste as much on the turn. There is an optimal tradeoff.
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Re: Question about 200 meter straight

Postby DJG » Thu Nov 15, 2012 1:45 pm

user4 wrote:
DJG wrote:[
Now if Bolt drew lane 1 and Blake drew lane 4,5,or 6 would that affect the outcome of the race?
I would say no, it would make it closer but Bolt would still win. Would Bolt time's be slower?
I wouldn't bet the farm on it. His splits would be a little different, I believe, but he would still
run 200 m very fast. All lanes are equal. That's the only approach an athlete or a coach can take.
I don't see lane-draws guaranteeing anything.
FTR: I believe lanes should be assigned by place and then time from the semi-finals. No draws after the first round, period. You want lane 4 or 5, earned it. Or let the qualifiers pick their lane
in the order they qualify: Bolt wins his semi with the fastest 1st place time, let him pick which lane he prefers. That would be fine with me.


That is a fine solution. As gh said, lanes matter allot and letting the accomplishments of the athlete instead of the draw of a straw would be a solution, and one that has been advocated on this forum before.


User4, Awhile back I sent an email to the IAAF and asked about the draws instead of lanes assigned based on place and time from the semifinals. The reply I got said that no national body has raised the issue. For a change to occur in lane assignments the motion for a vote must come from the NGB's. I guess the US athletes have never asked USATF to look into this.
Maybe the Jamaicans can get things going. Or maybe everyone is just happy letting lane draws determined medals as GH says.
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Re: Question about 200 meter straight

Postby DJG » Thu Nov 15, 2012 1:50 pm

mal wrote:
DJG wrote:
gh wrote:"all lanes are equal" may be a great motivational speech to give to your athletes, but unfortunately it defies the laws of physics.

If you've ever sat in on the technical meeting at a pro-level invitational and seen the heated pissing matches that go on over regards lane assignments, you'll know that the big-name athletes very much believe the draw makes a difference.


Fortunately, the laws of physics apply to all lanes and the tracks these big-name athletes are running on are the best-designed and best-engineered tracks that money can buy. So I am glad I have never witnessed the scene you describe. I might say "teach your athlete how to run the curve better!"


All lanes are equal still works for me. Even lane 1 in which hardly any sprinter has to run.

Q.) Are these Olympic and WC tracks banked ever so slightly?


GH is absolutely correct.

And a mistake you make is saying these tracks are the best engineered and best designed. That's not always so.

And finally (for me) the lanes are only equal if you are slow. The faster you run, the less fun it is on an inside turn. I'd guess that anything over 21.5 is almost like a straight to a top guy. When you are sub 21 it starts to play with you. :mrgreen:


mal, if OG and WC tracks are not the best, then why aren't they the BSET?
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Re: Question about 200 meter straight

Postby user4 » Thu Nov 15, 2012 2:50 pm

DJG wrote:
mal wrote:
DJG wrote:
gh wrote:"all lanes are equal" may be a great motivational speech to give to your athletes, but unfortunately it defies the laws of physics.

If you've ever sat in on the technical meeting at a pro-level invitational and seen the heated pissing matches that go on over regards lane assignments, you'll know that the big-name athletes very much believe the draw makes a difference.


Fortunately, the laws of physics apply to all lanes and the tracks these big-name athletes are running on are the best-designed and best-engineered tracks that money can buy. So I am glad I have never witnessed the scene you describe. I might say "teach your athlete how to run the curve better!"


All lanes are equal still works for me. Even lane 1 in which hardly any sprinter has to run.

Q.) Are these Olympic and WC tracks banked ever so slightly?


GH is absolutely correct.

And a mistake you make is saying these tracks are the best engineered and best designed. That's not always so.

And finally (for me) the lanes are only equal if you are slow. The faster you run, the less fun it is on an inside turn. I'd guess that anything over 21.5 is almost like a straight to a top guy. When you are sub 21 it starts to play with you. :mrgreen:


mal, if OG and WC tracks are not the best, then why aren't they the BSET?


Hello, it has nothing to do with being the best or better, There is no way to change the fact that the inside lane is at a severe disadvantage. I would even suggest that the adverse effect is measurable at times above 21.5. As reported above, just do the math.

Possible solutions 1) move to a 200m straight ...2) let the performance in the semi fully determine the lanes. No draws can be used. Athletes get to decide based on their performance during the semi.
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Re: Question about 200 meter straight

Postby Popout » Thu Nov 15, 2012 6:19 pm

DJG wrote:
gh wrote:"all lanes are equal" may be a great motivational speech to give to your athletes, but unfortunately it defies the laws of physics.

If you've ever sat in on the technical meeting at a pro-level invitational and seen the heated pissing matches that go on over regards lane assignments, you'll know that the big-name athletes very much believe the draw makes a difference.


Fortunately, the laws of physics apply to all lanes and the tracks these big-name athletes are running on are the best-designed and best-engineered tracks that money can buy. So I am glad I have never witnessed the scene you describe. I might say "teach your athlete how to run the curve better!"


All lanes are equal still works for me. Even lane 1 in which hardly any sprinter has to run.

Q.) Are these Olympic and WC tracks banked ever so slightly?




Speaking of physics *geek moment* im pretty sure that the answer to the original original question has to do with the mix and balance of centripetal and centrifugal forces. Sprinters build up momentum in the curve (centripetal, part of the reason they naturally lean in) which then "sling shots" (centrifugal) them out as they head into the the straight away. When running a straight 200 there is no momentum help from the sling shot effect to propell you.
Also, another factor could be mental perception. you are more likey to run faster when you can readily see the finish line. in the straight 200 the finish line appears waaaaay down yonder. But, the finish in the curved 200 is right across the field.

Just my 2 cents :)
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Re: Question about 200 meter straight

Postby tandfman » Fri Nov 16, 2012 7:40 am

user4 wrote:Possible solutions 1) move to a 200m straight

In many facilities, that's simply not possible. There's not enough room to extend the straightaway back that far.
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Re: Question about 200 meter straight

Postby Marlow » Fri Nov 16, 2012 8:21 am

Popout wrote:Sprinters build up momentum in the curve (centripetal, part of the reason they naturally lean in) which then "sling shots" (centrifugal) them out as they head into the the straight away.

F'real? That's the science of it? I don't see how you 'magically' (to me) get more speed just because you come off a curve. There is an acceleration factor because you are no longer expending energy fighting the curve, but does 'centrifugal force' really accelerate a runner as you describe? :?:
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Re: Question about 200 meter straight

Postby JRM » Fri Nov 16, 2012 10:02 am

Marlow wrote:
Popout wrote:Sprinters build up momentum in the curve (centripetal, part of the reason they naturally lean in) which then "sling shots" (centrifugal) them out as they head into the the straight away.

F'real? That's the science of it? I don't see how you 'magically' (to me) get more speed just because you come off a curve. There is an acceleration factor because you are no longer expending energy fighting the curve, but does 'centrifugal force' really accelerate a runner as you describe? :?:


No, not f'real. The "slingshot" concept is a misinterpretation of what's really going on when a sprinter comes off the curve. Yes, their velocity increases, but not because the curve "gives them" energy. They simply don't have to fight the curve anymore, and along with a change in posture, can devote all of their effort to forward motion.

Real slingshots work because you give them a flick of the wrist before letting go (more energy). Gravitational slingshots work because spacecrafts fall into (zero energy expenditure) orbits, but gain energy from the rotation of the body they're orbiting. Sprinters, however, do not get any external energy from the curve.
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Re: Question about 200 meter straight

Postby user4 » Fri Nov 16, 2012 11:19 am

To clarify above JRM and Marlow just said roughly the same thing.

Back to the history of it, before Tommie Smith's 19.5 Dave Sime was WR holder for the 200m straight and he never amounted to much on the 200m curve. Just an observation of the plausible disadvantage the old tighter 200m curved dirt tracks had on the bigger guys. From the SI vault:

http://sportsillustrated.cnn.com/vault/ ... /index.htm
Last edited by user4 on Fri Nov 16, 2012 1:49 pm, edited 2 times in total.
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Re: Question about 200 meter straight

Postby mal » Fri Nov 16, 2012 12:36 pm

DJG wrote:
mal wrote:
DJG wrote:
gh wrote:"
mal, if OG and WC tracks are not the best, then why aren't they the BSET?


They are usually the best that the lowest tender, and cheapest available land can provide.
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