Ceteris paribus, a slightly rolling course may give a slight time advantage by varying muscle use for uphill vs downhill and reducing overuse fatigue. That's not my experience, but it potentially could be for some runners.
Ceteris paribus, a slightly rolling course may give a slight time advantage by varying muscle use for uphill vs downhill and reducing overuse fatigue. That's not my experience, but it potentially could be for some runners.
BraveyNation brought to you by Champion wrote:
https://www.flotrack.org/video/5278820-ryan-hall-runs-american-record-time-20458-at-2011-boston-marathon
Monster tailwind that year, his 2:06.17 in 2K8 at London is more accurate. His 59:43 Houston half-marathon was crushin' it too. I don't think he can legit claim the 2:094 though, too much point-to-point tailwind that year.
Jon Arne Glomsrud wrote:
One cannot compare a ball on a rolling track and running.
...but the physics is clear and it is for instance well documented by the Strava GAP-funtionality (on average figures for runners)
A ball rolling, wheel (tire) rolling, and feet running have quite a lot in common though. For instance, the instantaneous speed of the bottom of the tire, ball, or foot at the contact point has zero speed. The foot mimics a rolling ball at the contact point. The ball rolling in tracks comparison I linked shows that the physics is NOT saying that flat has to be faster. Maybe human physiology, kinesiology or whatever would show rolling courses are slower, but not physics, which is what I was pointing out.
The GAP is only for average running. For example, good downhillers can go considerably faster than GAP suggests for the effort.
The first Nike sub-2 event on the Monza track was slightly rolling, not flat, and, the rolling aspect was cited as a benefit.
Jon Arne Glomsrud wrote:
One cannot compare a ball on a rolling track and running. There is an explanation to why running differs. For a ball, the big difference to running is that it rolls. We have to land on the foot and we also change our running slightly into a hill and down a hill. Running economy depend a lot on storing the impact forces into the muscles and tendons and releasing this in the gait. Uphill this is reduced a lot and downhill this can increase, but not to the degree needed. So we have to use more energy when we climb up the hill and get less help from landing impact, and we need to use less energy downhill, but are not as efficient at using the "free" energy from gravity throught he impact forces. This makes us less efficient for a rolling course than a flat one.
Mental aspects can still make us perform better than theory and make up for some of the difference, but the physics is clear and it is for instance well documented by the Strava GAP-funtionality (on average figures for runners)
No, running is not rolling a ball, but it does show that the people saying bAsiC pHySiCs don't know what they're talking about. Strava GAP is just a crude model that doesn't prove anything. For many people it is way too generous on both uphills and downhills. Running biomechanics are complicated. In my opinion it's possible that the change in nervous recruitment patters are beneficial, or that some people happen to be more economical going +1%/-1% than flat. There's no way Strava's GAP would be able to falsify this.
Rule Follower wrote:
Boston is downhill.
And could have a significant tail wind.
maybe with these conditions.
Race starts with a short steeper downhill segment to use gravity help a runner accelerate up to a high rate of speed faster than they could on the flat using the same amount of energy.
Then the incline flattens out but it is still slightly downhill. Most of the race distance is a long gradual downhill. The downhill is enough that a runners speed/pace is slightly faster than what they would be able to maintain on the flat.
As the runner gets to the final 100 meters or so of the course, their average overall speed/pace should has been faster than what they could maintain on a flat course. Their net time to this point is less than it would be if the entire course was flat.
The final 100 meters or so of the course (lets say for a one mile race) is enough uphill so that the overall net climb/descent of the course is zero. The runner attacks this final 100 meters, shifting gears, changing form and kicking it in to the finish line. The runner goes anaerobic during this segment and into severe oxygen debt, Their pace over this final uphill segment slows some when compared to the majority of the race. But not enough so that all the time they gained on the downhill is lost.
The uphill at the end is better than the uphill at the start (unless the race is really long and muscle fatigue is a concern) because you can overcome the negative effects of an uphill at the end by going into oxygen debt,
The runner finishes with a time slightly less than they would have run on a flat course.
For people who never took physics and are citing that ball rolling example,
potential energy = mgh (mass * acceleration of gravity * height)
kinetic energy = .5mv^2 (one half * mass * (velocity)^2)
One of the key reasons humans do not behave like balls is friction. The above formulas ignore friction because typically friction is very low for experiments like the one in the video shown earlier. Humans, however, have much, much more friction than balls, so the above equations do not come anywhere remotely close to accurately describing what happens to human runners as they run down a decline. Notice that the v is squared in kinetic energy.
The answer to the question is no for all intents and purposes.
Also, people should stop citing courses that are net downhills.
dsafdsfds wrote:
For people who never took physics and are citing that ball rolling example,
potential energy = mgh (mass * acceleration of gravity * height)
kinetic energy = .5mv^2 (one half * mass * (velocity)^2)
One of the key reasons humans do not behave like balls is friction. The above formulas ignore friction because typically friction is very low for experiments like the one in the video shown earlier. Humans, however, have much, much more friction than balls, so the above equations do not come anywhere remotely close to accurately describing what happens to human runners as they run down a decline. Notice that the v is squared in kinetic energy.
The answer to the question is no for all intents and purposes.
Also, people should stop citing courses that are net downhills.
I took plenty of physics as an engineer. Citing "physics", a couple equations, and hand waving about friction doesn't prove anything. If you want to cite physics, show your work -- in detail, LOL.
This isn't a physics question is all I'm pointing out but showing the ball rolling. I'm not arguing for a non-flat course as optimal, I'm picking on the citation of "physics" without showing supporting work. It's in response to what someone said earlier, the simplistic, "You always lose more on the uphill than you can gain on the downhill." I guarantee that person would have been confused watching the rolling balls video on mute, because they had a little knowledge, but applied it wrongly. This is more a physiology/kinesiology question.
dsafdsfds wrote:
Bad Wigins wrote:
It is impossible for a course to be perfectly flat because of the curvature of the Earth.
This helps marathoners not because it's flat, but because the distance is far enough that they're going significantly downhill in every direction.
If you had an ultramarathon all the way around the world, it would have a drop in elevation twice the diameter of Earth, but also no drop at all.
(nyer nyer nyer definition of "elevation" nyer nyer nyer)
Whether you're running in a straight line or downhill has nothing to do with the horizon or the ocean.
Because the runner is moving forward along a tangent line to Earth's surface, each footstrike is slightly below the tangent line from where the last foostrike was. And that's a fact, Jack. Try and disprove it if you're foolish enough.
pie day wrote:
dsafdsfds wrote:
For people who never took physics and are citing that ball rolling example,
potential energy = mgh (mass * acceleration of gravity * height)
kinetic energy = .5mv^2 (one half * mass * (velocity)^2)
One of the key reasons humans do not behave like balls is friction. The above formulas ignore friction because typically friction is very low for experiments like the one in the video shown earlier. Humans, however, have much, much more friction than balls, so the above equations do not come anywhere remotely close to accurately describing what happens to human runners as they run down a decline. Notice that the v is squared in kinetic energy.
The answer to the question is no for all intents and purposes.
Also, people should stop citing courses that are net downhills.
I took plenty of physics as an engineer. Citing "physics", a couple equations, and hand waving about friction doesn't prove anything. If you want to cite physics, show your work -- in detail, LOL.
This isn't a physics question is all I'm pointing out but showing the ball rolling. I'm not arguing for a non-flat course as optimal, I'm picking on the citation of "physics" without showing supporting work. It's in response to what someone said earlier, the simplistic, "You always lose more on the uphill than you can gain on the downhill." I guarantee that person would have been confused watching the rolling balls video on mute, because they had a little knowledge, but applied it wrongly. This is more a physiology/kinesiology question.
If I don't cite well understood physics then the physics don't exist. Okay. Gotcha.
I hope you are not an engineer because you apparently don't understand HS level physics. Saying this is a physiology/kinesiology problem more than a physics problems further demonstrates your ignorance. Human bodies do work. Work is a physical process, as in physics. Even cars get better gas mileage on flat vs rolling terrain. You would think someone who spent any time at all studying engineering would know that...
I honestly don't know how this isn't common sense/knowledge. Besides being intuitive, results speak for themselves. On top of that, I believe this very thing is written about either in Lore of Running by Tim Noakes or Better Training for Distance Runners by Martin and Coe. I can't remember which because it's been more than a decade now since I read them.
this and this wrote:
maybe with these conditions.
Race starts with a short steeper downhill segment to use gravity help a runner accelerate up to a high rate of speed faster than they could on the flat using the same amount of energy.
Then the incline flattens out but it is still slightly downhill. Most of the race distance is a long gradual downhill. The downhill is enough that a runners speed/pace is slightly faster than what they would be able to maintain on the flat.
As the runner gets to the final 100 meters or so of the course, their average overall speed/pace should has been faster than what they could maintain on a flat course. Their net time to this point is less than it would be if the entire course was flat.
The final 100 meters or so of the course (lets say for a one mile race) is enough uphill so that the overall net climb/descent of the course is zero. The runner attacks this final 100 meters, shifting gears, changing form and kicking it in to the finish line. The runner goes anaerobic during this segment and into severe oxygen debt, Their pace over this final uphill segment slows some when compared to the majority of the race. But not enough so that all the time they gained on the downhill is lost.
The uphill at the end is better than the uphill at the start (unless the race is really long and muscle fatigue is a concern) because you can overcome the negative effects of an uphill at the end by going into oxygen debt,
The runner finishes with a time slightly less than they would have run on a flat course.
This is it. I think for an aerobic race without other factors flat is always going to be faster. You lose more on the uphill than you gain on the downhill.
But say for a mile race on the track. I'd climb 2 m in the first 20 m and another 2 m in the final 20 m if you gave me a 4 m decent in the last 200 m.
Likewise for the 100m where you are limited in part by your ability to get up to top speed I think maybe a 2 m decent over the first 20 m might more than offset for a 2 m climb in the last 10 m. By that point they have so much momentum that they might not lose as much time as they gain at the start.
Otherwise flat is going to be faster. Unless you have other factors like sun/shade, wind, temperature, etc. I ran a short loop multiple times today and I switched directions because it was easier to go uphill on the shady part of the loop and downhill on the sunny part.
Reminds me of a HS XC course where it was basically 1 mi uphill, 1 mi flat, and 1 mi downhill. I certainly wouldn't have wanted to run it any other way.
Imagine you have a car that gets 30 mpg. Then imagine driving your car 30 miles up a very slight, but consistent hill. It'll take more than 1 gallon, sure, but definitely not 2 gallons - the car certainly isn't working twice as hard going up that hill. Probably like 1.05 gallons total.
Now put the car in neutral and cut the ignition, and it'll roll all the way back to the start. You then traveled 60 miles on just over a gallon of gas, whereas driving on flat ground it would have taken 2 gallons.
Same principle here, assuming your shoes have wheels and an efficient powertrain.
World half marathon progression, 58:01 Kamworor, Copenhagen, slightly undulating course. 57:32 Kandie, Valencia, flat course.
Another giver of +1. wrote:
World half marathon progression, 58:01 Kamworor, Copenhagen, slightly undulating course. 57:32 Kandie, Valencia, flat course.
My mistake, was thinking of the 15k WR on seven hills course.
reality checkers wrote:
Imagine you have a car that gets 30 mpg. Then imagine driving your car 30 miles up a very slight, but consistent hill. It'll take more than 1 gallon, sure, but definitely not 2 gallons - the car certainly isn't working twice as hard going up that hill. Probably like 1.05 gallons total.
Now put the car in neutral and cut the ignition, and it'll roll all the way back to the start. You then traveled 60 miles on just over a gallon of gas, whereas driving on flat ground it would have taken 2 gallons.
Same principle here, assuming your shoes have wheels and an efficient powertrain.
I get your point but a car isn't going to roll down a hill that is 30 miles long and only takes an extra 0.05 gallons (less than 1 cup) of gas to climb versus a 30 mile flat.
But there is a big difference between rolling and running. If this were a biking conversation than the answer may be different.
Another giver of +1. wrote:
World half marathon progression, 58:01 Kamworor, Copenhagen, slightly undulating course. 57:32 Kandie, Valencia, very-slightly-downhill-in-all-directions course.
Fixed.
And also Kamworor's run was initially better than everything on a very-slightly-downhill-in-all-directions course. But then he's Mr. XC and probably likes hills.
Arguably hilliness allows you to rest certain muscles and work fresher muscles.
dsafdsfds wrote:
I hope you are not an engineer because you apparently don't understand HS level physics. Saying this is a physiology/kinesiology problem more than a physics problems further demonstrates your ignorance. Human bodies do work. Work is a physical process, as in physics. Even cars get better gas mileage on flat vs rolling terrain. You would think someone who spent any time at all studying engineering would know that...
You over simplifed again and are exposed again when you do the "obvious" hand waving and don't even try to show your work. I've owned a Prius and have played around with hypermiling. The best results are actually in the mountains, using technique similar to what "reality checkers" described. Except you can do a lot better than RC described, by taking a much longer downhill instead back down to the same initial elevation.
Looked up the Fuelly record for my old Prius. I got 56.76 mpg for the tank over the continental divide on Interstates 80/76/70, starting elevation of 2800 ft. in North Platte, NE, ending elevation 4500 ft in Friuta , CO. The benefits of mountain terrain downs were so great that the mpg was great even with a net climb of 1700 ft. That 56.76 mpg was the second highest for a tank that I had our of the 78 fill ups that I had recorded for the car (highest was 57.59 mpg, average was 47.5 mpg). If I cherry picked the best mpg part with same starting/ending elevation over the divide, I think it was well into the 70s mpg.
But you would be going 70MPH up hill and 10MPH downhill. That is like running 5 minute mile uphill and 10 minute mile downhill.
We'll get a good indication on April 24th. We've got a world class field coming in to take advantage of our course, specifically designed with a max elevation gain of only 32'. www.valleyonemarathon.com