Boston analysis

After reading all the arguments throughout the past week I have come to the conclusion that road racing should be treated much the same as cross country in that different courses should not be be compared to each other. Stop trying to find a way to solve for how much aid the wind provided and just acknowledge that what happened last Monday was amazing. Maybe the IAAF should create a marathon course that is for world record purposes only (flat, no elevation drop, looped, etc.) so that there can be no doubt as to what somebody ran for 26.2 miles.

So here's another chunk of bloody red meat for malmo- an alternative, agenda-free wind analysis:

http://www.trackandfieldnews.com/discussion/viewtopic.php?f=1&t=42763

"In summary the wind was not THAT great a help because the inland official (10m up/airport settings) were 14-15, so ground level wind was 8-10 with gusts that were not always in the forward direction and the average vector was probably no more than 90% (for the finishing mile they make a 90 degree turn so one segment as net no aiding wind). Also, since their running speed is only just under 60% of sprinters 20-22m the quadratic nature of the wind effect brings this down to 33%. 8.8mph is 4mps and would aid a 100m time by 0.20 seconds or 2%. Taking one third of this yields 0.66%; this amounts to a bit under 1 minute."

While malmo keeps waving everybody off with "Nothing to see here, keep moving...pay no attention to the delusional idiotic anon cowards....", those of us who think that there is more to this race than some impressive airport wind readings will be keeping our eye on these athletes over the next year or so, by which time it should become increasingly clear whether this all represents just another run-of-the-mill Boston jacked up by a Kamikaze ("Divine Wind"), or a sea-change in the event itself. See you all in 2012!

OK, this is moving in the right direction. At least there is some analysis provided. I would hesitate to call this "agenda-free", however.

What you have just posted is simply someone else's post (who also posts here on LRC in case folks don't recognize the handle). "26m235" says, "...the wind was not THAT great a help..." and then goes on to claim that 15 MPH winds were really 9 MPH. Now, if I can see that confirmed by some reliable meteorology data source then I will be more inclined to believe that this was in fact true as opposed to an arbitrary claim by someone with an agenda.

This statement, "for the finishing mile they make a 90 degree turn so one segment as net no aiding wind", compared with this picture:

makes me question the notion that this is someone without an agenda. The "segment" without an aiding wind would appear to be reasonably described as microscopic, hardly worth noting for someone without an agenda.

At any rate, I do strongly agree with your summary: "those of us who think that there is more to this race than some impressive airport wind readings will be keeping our eye on these athletes over the next year or so, by which time it should become increasingly clear whether this all represents just another run-of-the-mill Boston jacked up by a Kamikaze ("Divine Wind"), or a sea-change in the event itself." Indeed, I would go further to say that we should also include those of us who do NOT think that there is any more to this race than a very good run by some world class athletes with a very large tailwind (I include myself amongst this crowd). A year from now we should all agree upon whether " this all represents just another run-of-the-mill Boston jacked up by a Kamikaze ("Divine Wind"), or a sea-change in the event itself." Of course, we won't. But we should.

I think we can all agree that it's going to be interesting to see how G. Mutai and Mosop do in the future and that whatever the impact of the Boston wind they are the real deal and as Renato Canova said in starting this thread they trained to run well in Boston.

While discussions like this are great for the sport -- even if one side is not going to convince the other there's something to be said about the Mays-Mantle-Snider aspect of the debate and the way it gets our enthusiasm for the sport going -- I wonder whether there's a sea change in perceptions, and that it will hurt Boston and New York.

I've thought of Berlin as a time trial, London and Chicago as competitive races in which time is important and Boston and New York (particularly without pacers) as being great races in which, as 722 just said, like cross the time is irrelevant. I think Boston loses something by trying to hone in on the we're-fast-too meme that London's had in the spring and that if everyone starts focusing on time uber alles people'll head to Chicago instead of New York in the fall. Which would be a shame because the symmetry of London & Chicago versus Boston & New York seemed to broaden the sport.

I'll add more, Yes 26m235 is a frequent poster and has posted that same opinion here.

He ignores the 19.7mph in favor of 15 mph then arbitrarily says that it is actually 9 mph. Then he throws out some reduction percentages due to less wind resistance.

The problem here is that Jonas' calculator already takes into account of less air resistance at slower velocities. 26m235 errs in that he want to double-reduce wind resistance.

The problem

(ventolin had already done this problem before)

A 2:03 marathon is 123 minutes

123 minutes is 7380s

7380/42195 = 17.49 per 100m segment.

Let's go ahead and say that the wind velocity was 9 miles per hour instead of 19 with 31 mile an hour gusts like it was.

I'll use 8.9 miles per hour instead of 9.0 becasue it is 4.0 m/s. I like round numbers.

Go to Jonas calculator plug in 17.49 4.0 20m altitude

http://myweb.lmu.edu/jmureika/track/wind/index.html

You get 0.445 per 100m or

0.445*421.95 = 187s or 3:07

I personally don't like these calculators because it is unknown what the formula is and I think that 3:07 is too high. Secondly who knows how much his math breaks down on the fringes? For the 100m the only factor is how much wind resistance reduces maximum speed. With a tailwind there is less resistance therefor the sprinter can go faster.

With a marathoner he still gets the benefit of a loss of air resistance, making him faster, but more important, he doesn't suffer the cumulative effort of work against that air resistance for those two hours. This is huge.

Jonas calculator gives a 2:03 marathon time with an 8.9mph tailwind 3:07 advantage. I'd bet than his calculator is off of and is only half that, but factoring in the additional benefit of energy not used fighting the air resistance, it's probably a push so we're back to that 3:07 figure again.

I will go on to tell you that I respect 26m235 opinion a lot. He generally plays fair and presents his case, but I think that he hasn't given as much of a look to this as he normally would.

So thanks to djconnel and Giovanni Ciriani for their inputs on this, which I'm pasting directly below:

Assume a human is 1.7 meters tall by 40 cm wide, with Cd close to 1 for a cylinder with normal wind incidence. That's CdA = 1.5 meters squared. Then assume the wind is blowing at around 2 m/sec (very fast for road-level given how fast these guys are running) with an air density near 1.2 kg/m-cubed. That's 6.25 N = 6.25 kJ/km. Minetti measured close to 3.4 kJ/km/km for running:

http://jap.physiology.org/content/93/3/1039.full

. So if a runner weighs 60 kg, that's 204 J/m, of which the tailwind is saving 6.25 J/m, which if speed is proportional to power, is 3.8 minutes saved. (courtesy djconnel).

So that's 3 min and 48 seconds.

And then there is this, the wind resistance and relative velocity argument:

Aerodynamic drag for a runner is about 3% of forces acting against him/her. Today's wind in Boston (according to wunderground.com) was 14 mph W to E, which is just about the same speed the top runners were running at. Therefore the runners didn't experience aerodynamic drag. Since their power output remained the same, a 3% advantage translates directly into a 3% higher speed, and a 3% lower time = 3 min and 36 sec. (Courtesy G. Ciriani)

I'm going to work with an engineer to see if it's possible to refine the assumptions a little and work towards a clearer understanding of the physics. However, we're in the ball park of 2 to 3%, 3 to 4 minutes. Now, let's compare that to performance variations.

JKs pre event guess. 3-4 minutes wouldn't shock him.

My post race guess - 3-4 minutes

according to Jonas calculator 3:08

according to djconnel and Giovanni Ciriani 3:36 aand 3:48

All of us have supplied a rational behind our estimates. The flatearthers only defense is that we hate Ryan Hall, and/or Mutai, or Boston, or else we are bitter and jealous that we can't run 2:03.

ITS THE WIND, STUPID.

I agree that the debate is good for the sport. What's bad is the debate on whether or not they should count for records. Yes they should, then we debate over whether or not, say, Wanjiru's Olympic run is "better" than the World Record (2:03:02) or if Geb's time (# 3 all time) is "better".

This calculator is based on Jack Daniels' work. Punch in the numbers on the bottom section and give a conservative 8 mph tailwind and it translates to something like a time of 2:09 instead of 2:03. I used 4:42 min/mile and 8 mph tailwind, it returned a 4:57 m/m pace in no wind.

http://www.runworks.com/calculator.html

Again, not sure of the algorithms involved so take it for what it's worth.

malmo, you show your hand every time you finish a post with a simplistic mischaracterization of any analysis that departs (doesn't even have to entirely disagree) with your chigger-like position. I frankly couldn't care less whether you "hate Ryan Hall, blah,blah". As far as "flatearther", aren't those the guys that dismissively say "LOOK AROUND YOU, THE EARTH IS FLAT, STUPID"?

What I find laughable is your attempt to delve into the area of environmental physiology with no concept of multifactorial influence of the environment on the organism (performing athlete, in this case). Just as a for instance, in your mustering of J/m saved by a tailing wind, you completely neglect efects of reduced evaporative cooling for the athlete running in a wind-neutral situation, and the possible resulting hydration/cooling stress as a counter to the aiding effect of the wind. Of course, in the perfect-world "flat earth" view that you maintain, hydration issues and temperature stress don't exist in the marathon.

I have also posted a thread on the disparity between weather station recordings and track-level records here:

http://www.letsrun.com/forum/flat_read.php?thread=4017191

My cursory findings lend support to what 26mi38yd has to say, with regards to ACTUAL wind vectors experienced by the athletes. "Hurricane at their backs" indeed.

You are flunking out of 200-level biology here.

"attempt to delve into the area of environmental physiology with no concept of multifactorial influence of the environment on the organism (performing athlete, in this case). Just as a for instance, in your mustering of J/m saved by a tailing wind, you completely neglect efects of reduced evaporative cooling for the athlete running in a wind-neutral situation, and the possible resulting hydration/cooling stress as a counter to the aiding effect of the wind."

A dense socialistic fog that means absolutely nothing.

On the first day of class we discussed the possible effect of overheating due to diminished evaporation. Negated due to the sub 50 degree temps and extremely dry air (the dew point was 25 degrees, about what you'd find in Phoenix).

You're serious, you actually started anther thread to say that the wind on the track at Wallace Wade, which is dug into the side of a hill, is less than the readings at the airport?

Keep attacking those windmills, el Don.

I'll try again...

From the "Lore of Running" by Tim Noakes, pg 61...

"Davies found that the effect of a tailwind was about half that of a headwind (although obviously this effect was to the athlete's advantage). Thus, as discussed, a tailwind of 19.8 km per hour is of little assistance to runners running slower than 18 km per hour, but a tailwind of 19.8 km per hour would assist a marathon world record attempt by increasing the runner's speed .5km per hour. Higher tailwind speeds of 35 to 66km per hour would improve running speeds by 1.5 to 4km per hour."

Therefore...based on this study...a 20mph unobstructed tailwind would improve marathon times by around 8 minutes. Those that are saying it's a 3-4min aid are taking into account the fact that the wind is blocked in spots and not at full velocity at all points on the course. They are being conservative...and more importantly...using common sense.

I suppose you could say this study lacks credibility or whatever. But this book is generally respected.

Do you realize the top guys ran the second half of the marathon, the part with all the uphills in just over 1:01? Think about it...

Apparently, you don't understand the type of athlete we're dealing with here. They ran the mile including the Newton hills in the low 4:30s, infact therefore proving that the athletes actually in a way have an unfair advantage(kind of) because of the way the course is set up, not neccesarily the wind.

The wind measurements taken on the course, at ground level:

ZERO, ZIP, NADA.

A mid-level high school track meet has more accurate, real-world data to work with, yet you are attempting to build a performance model with NO ON-SITE METEOROLOGICAL OR PHYSIOLOGICAL DATA whatsoever. Only mud-and-sticks wind calculators designed for sprinters and some numbers taken from 30 feet in the air, miles away. You are pulling 3.5 minutes out of your flatearther knuckledragger ass, I'll pull 2.0 out of my delusional socialistic one. The difference, of course, is a solid run vs. world-record-level performance.

To the guy with the 1:01+ split: you must be talking about the 13.1 miles that has a net drop of almost 150 feet, run by guys at/near 2:03 shape. Yeah I'm fully aware of that. It's what they SHOULD be running if they are in WR contention.

Crimea River wrote:

The wind measurements taken on the course, at ground level:

ZERO, ZIP, NADA.

A mid-level high school track meet has more accurate, real-world data to work with, yet you are attempting to build a performance model with NO ON-SITE METEOROLOGICAL OR PHYSIOLOGICAL DATA whatsoever. Only mud-and-sticks wind calculators designed for sprinters and some numbers taken from 30 feet in the air, miles away. You are pulling 3.5 minutes out of your flatearther knuckledragger ass, I'll pull 2.0 out of my delusional socialistic one. The difference, of course, is a solid run vs. world-record-level performance.

To the guy with the 1:01+ split: you must be talking about the 13.1 miles that has a net drop of almost 150 feet, run by guys at/near 2:03 shape. Yeah I'm fully aware of that. It's what they SHOULD be running if they are in WR contention.

Weird post ^. IMHO.

At any rate, I hope that you will do us all a favor and come back on here a year from now with this \/ in mind:

"keep your eye on these athletes over the next year or so, by which time it should become increasingly clear whether this all represents just another run-of-the-mill Boston jacked up by a Kamikaze ("Divine Wind"), or a sea-change in the event itself."

(My thanks to the poster of the above quote who does not agree with me regarding the significance of this year's Boston but whose conclusion I certainly appreciate.)

I will be sure to do the same.

Guys this is basic physics. If you have a 20 mph tailwind let's say, your energy expenditure vs. no wind is less. I'd love a 20 mph wind pushing me during a 10k even. To say otherwise proves a lack of understanding of basic physics.

Plus, this "help" continued for over 2 hours, whereas normally you'd have a greater energy expenditure for 2 hours. The comparison between those two situations is very huge due to the cumulative effect. To say that a strong tailwind doesn't help is like saying a strong headwind doesn't hurt.

physicsman wrote:

Guys this is basic physics. If you have a 20 mph tailwind let's say, your energy expenditure vs. no wind is less. I'd love a 20 mph wind pushing me during a 10k even. To say otherwise proves a lack of understanding of basic physics.

Plus, this "help" continued for over 2 hours, whereas normally you'd have a greater energy expenditure for 2 hours. The comparison between those two situations is very huge due to the cumulative effect. To say that a strong tailwind doesn't help is like saying a strong headwind doesn't hurt.

Whoah, dude! That is WAY over our heads. But thanks for trying to being us up into, what? at least the stone age.

Me, I'm sticking with 3:40. And you can hold me to it a year from now.

Crimea River wrote:

To the guy with the 1:01+ split: you must be talking about the 13.1 miles that has a net drop of almost 150 feet, run by guys at/near 2:03 shape. Yeah I'm fully aware of that. It's what they SHOULD be running if they are in WR contention.

You're kidding? The 1:01 over the last half is the evidence that something was amiss. All of the difficulty in any marathon, even flat ones, is in the 2nd half of the course. Now you have Boston, where all of the difficulty is in the 2nd halt yet they run it in 1:01. A strong tailwind that you delusional nutjobs want to pretend wasn't there is responsible.

You get the the half marathon mark in 1:02:00. You didn't have to work as hard as you would on the flat course because of 1) a 300 foot drop in the first 4 miles, and 2) a 20mph wind at your back for 13 miles.

At the 15 mile mark you have the first drop of the rollercoaster, a series of 4 hills beginning at Newton Lower Falls and culminating at Heartbreak. Yet in the most difficult part of the course, they run it in 1:01:00 and you think that it wasn't the wind?

You're a troll.

You haven't been paying attention.

I've already said that the lead runners picked up around two minutes overall due to the wind- you keep claiming that I think the wind gave them nothing, which is a lie. Second, I postulated (which is all that ANY of us can do here, without better field data) that the reason the top men picked up more time than the women or the rest of the field was because they ran more aggressively through Wellesley/Newton than anybody else (thanks to Hall, a factor you choose to ignore) and picked up time since a tailwind should help more on flats/uphill than on downhills (a notion you, typically, scoffed at).

So, on a back-of-had calculation, my estimate of the time they picked up in the second half due to wind would be 90+ seconds, for an adjusted second-half time of 62+, very realistic indeed for runners pushing the record envelope over a net drop course.

Of course you'll dismiss this and just add another spitball to "delerious, idiot, socialistic, flatearther troll" and I will only have to laugh; you are like a Monty Python skit with this:

http://www.youtube.com/watch?v=teMlv3ripSM

From my training on windy hills I strongly suspect that a tailwind helps more on mitigating uphills than on a flat. I would expect that if we commissioned a study of oxygen uptake on uphills with and without a bigger and bigger tailwind we would find that tailwinds virtually flatten hills.

I think that is what happened in Boston to get the 1:01 second half.

Sorry if it is no fun to agree with Malmo.

Tom

a vote for the obvious here - it was the wind.

UNLESS Mutai and others start running 2:03x - then, we should revisit the thread.