That pace would get you a marathon time of about 9mins 56secs ;)

Constant output is time-minimizing if and only if conditions are constant.

Covered

"Assuming the following for both run & bike :
a) Dead flat course
b) No or steady wind"

Hugh

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Genetics load the gun, lifestyle pulls the trigger.

Couldn't there be non-constant conditions such that constant output would still be time minimizing? Say, in cycling, a tailwind combining perfectly with a slope?

Unlikely in the real world, but still possible.

Your physiological condition is not constant.

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"Go yell at an M&M"

EDIT: 4:15 min/km ... must be tired ;) Thanks

Your physiological condition is not constant.

THIS^^^^^^
So to answer your question, no....

Agree with Ken and Monty on this one.

Perhaps you, Ken and Monty can expand and be of greater use to the OP;) He seems to be asking whether there is research that shows it's most ideal to run or ride and even pace or even power for the whole duration of a flat non wind affected course or is there a better alternative supported by research. None of us has answered this question. Of course this is Slowtwitch so we're all too busy correcting each other.

Hugh

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Genetics load the gun, lifestyle pulls the trigger.

The point is that the "conditions" of the race must include the physiological conditions of the racer, and since everyone's physiology is somewhat different, there can't be an ideal way to pace. There can be guidelines, but some physiological types might be better off burning candles earlier, and some by saving them for later.

I once did a decathlon in college, and I sought out our best 400m runner for advice on how to run that event. He said "running a 400 is like running into a mud pit: you're going to slow down no matter what, so you should go out as hard as you can."

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"Go yell at an M&M"

He seems to be asking whether there is research that shows it's most ideal to run or ride and even pace or even power for the whole duration of a flat non wind affected course or is there a better alternative supported by research. //

Well you have to qualify what distance you are going first, and the OP seemed to be pointing to ironman distance. In a 4k pursuit it might be right to go most of it as steady as possible against the red line that race requires. But when you talk about several hour races now you are adding in the things that happen to every body. He did not qualify about how hot or cold it would be in this TT, and that is a huge factor in how you would pace and most likely you would be varied in that pace. And even that has to be qualified as to the particular talents of each individual athlete to handle, or excel in certain types of weather. One athlete might be 100% at 55 degrees, while another freezes up and is optimal at 75.


The OP is looking for an exact equation for optimal performance, and once you throw in the human body, there is not one exact formula. Especially for a 9 hour+ race...

I recall seeing videos of swimmers being video analyzed with drag strings attached to their torsos. It made it possible to see if they were surging or keeping a constant speed. The reason why is that slowing down and then speeding up when you really don't need to wasn't as fast as keeping a constant speed. Since water has so much more drag, it's a great exaggerator of conditions to help us see the results more clearly. Slowing down is "braking" and re-accelerating up to speed is subjecting your body to moments of overdrive, which burns matches over time. The same thing applies to why you wouldn't run heel striking too much - braking then requires overdriving, and why do that when you could just keep a constant speed.

So all that is at a micro scale, but *should* scale up to a macro scale, such as pacing for an entire race. Surging is probably bad, M'kay.

Agreed on the physiology not being constant. So maybe using effort (PE 7 out of 10) as the speed would be better.

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The only study I recall was of female college distance runners for a 5k. The fastest group did the front 1/2 hard. That approach produced better results than negative or even splits. I wish I could find it.

not a study, but if you look at running world records for pretty much all distances from 1500m to the marathon have been set with a small negative split. I remember the study you mention. In cross country you need to get up near the front early on so there is a real bonus for hammering the start. The really speedy girls can do this and still hold on the rest of the way. I would bet that the same women could run the course faster if they did a pure time trial at a more even pace.

Hugh

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Genetics load the gun, lifestyle pulls the trigger.

Assuming you're asking about a half or full distance, what other possible strategy do you think could beat a steady state? Just one idea?!

i think that our friend sir roger bannister actually did a thesis on this while doing his MD at oxford and training for the 4-minute mile.

now, i believe he was using treadmills, so that controls for conditions nicely, but his finding was that, all else equal, a steady effort was best.

-mike

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https://lshtm.academia.edu/MikeCallaghan

http://howtobeswiss.blogspot.ch/

A pretty strong real world indicator is that the last 5 times the marathon world record has been broken the second half has been plus or minus 30 seconds from the first half.

Pfitzinger maintains that the average Joe should plan to pace the second half 2 to 3 percent slower since running economy goes down as slow-twitch fibers fatigue and some fast-twitch fibers are recruited. Something that is less pronounced in the pros. Not sure what studies if any that conclusion is based on though.

..

now, i believe he was using treadmills, so that controls for conditions nicely, but his finding was that, all else equal, a steady effort was best.

-mike //

For the mile race. Much like my 4k pursuit example, 4 minutes is hardly comparable to races that take hours. And what really are we talking about when we say even paced? Even power, even running pace, even physiological output? That makes a big difference until you quantify what "even" actually refers to..

My question would be how are anaerobic energy sources used and how does using them affect aerobic energy use. Are they metered out slowly during long efforts until they are depleted or are they saved for periods when higher energy output is requested? Can you use anaerobic energy sources at the start of a race and maintain your theoretical max aerobic energy output when the anaerobic energy is gone (or save it until the end)? That seems like the only possible alternative that could be better than totally steady output.

Let's look at the bike question, as that's easier to address since "intensity" is more easily quantified.

For the bike, I'm going to assume we can substitute "power" for "intensity" in the original question. For argument's sake, I'm going to ignore the metabolic side of the equation for the moment, and just assume (although I don't beleive it's true) that if we exceed our sustainable power threshold by a certain amount of watts for a certain amount of time, we can metabolically recover by riding for an equal amount of time at the same watts below our power threshold. In other words, we ride a little faster than threshold at times, a little slower at times, but the average watts put out over time is equal to the threshold power output.

So let's just look at the physics of that, taking into account the basic aerodynamic tenet that drag increases with the square of speed. For simplicity's sake, I'll use the following cycling power/drag/speed calculator and the default values other than power: https://www.gribble.org/...g/power_v_speed.html

At a steady 200 watts of power output, our theoretical cyclist will travel 33.35km in one hour.

Alternating back and forth between equal intervals of 225 and 175 watts, our cyclist will travel 33.28km in one hour.

Alternating back and forth between equal intervals of 250 and 150 watts, our cyclist will travel 33.07km in one hour.

No combination of above and below threshold that equals the same average output as threshold results in a faster average speed. Why? Because at higher power output, more power is lost to aerodynamic drag than is saved at lower output because of the exponential nature of the relationship between drag and speed.


So in order for a non-steady output to be faster, you'd have to be able to fully recover from a period of increased output in less time than you spent at the increased power output. That seems highly improbable, given that metabolic costs of riding at output beyond threshold are also exponential:




There's not nearly as much metabolic savings to be had for riding below the power threshold as it costs to ride an equal amount above. Riding over threshold takes a lot out of you, but there's not a lot of metabolic headroom for recovery at lower intensities.

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"They're made of latex, not nitroglycerin"

I don't think you can quantify this- but positive splitting (1st half intentionally harder), is a bad plan for long events.
There is no formula for how much someone will degrade over time.
One day you might crack a little (from starting too hard)- another day you may fully implode.
Depends on many factors. How hard 1st half is, distance, weather conditions, course profile, fueling, glycogen levels, how rested the athlete is...

But if you want to see where you will crack- start hard. You will likely find out.

Great contribution, and I think you're on the right track. Just pointing out that the OP specified marathon/180km, so centering your discussion on above/below threshold probably isn't appropriate. At those distances it's idiotic to go over threshold except when taking into account short-term tactics, like the psychological warfare of destroying the will to compete of a competitor you're passing by throwing down a short surge.

When I speak of "threshold", I don't necessarily mean your formal FTP figure. By "threshold," I mean the maximum steady power/intensity you can sustain for the duration of the particular race at hand, however long/far that may be.

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"They're made of latex, not nitroglycerin"

That's what I figured. But then you run into issues with the graph you posted. Because the exponential bit occurs at LT2 and there's a local minima in lactate concentration around 175W! :) So an optimal strategy going over LT1 then dipping back to 175W to recover. :)

I think the even-pacing theory is based on a monotonically increasing metabolic cost for increased output (in combination with monotonically increasing drag for increased pace).