Thoughts on Running Economy

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Kim Stevenson

59 posts since
Dec 14, 2007

180. Dec 1, 2007 1:30 PM

in response to: Richard99

Geez Guys ! why are we bothering !. 24 hrs ago I thought I would open a book and throw in some bits that looked like they may stir things up.
Then I went and ran with my athletes and for my trouble had a nasty fall because I am a very efficient runner, not lifting my feet from the ground very far when running at "slow speeds".I did not notice a rock on the path and tripped on it. All good now just sporting some nasty grazes !.
I notice my buddies have taken their ball and gone home and I am going to do the same.
I am heading out the door to work with an athlete who has a chance of a National High School podium finish next weekend.
You see Richard this thing is about working with real people and trying to make them better athletes than they already are. Yes ! sometimes we make mistakes but I know we are on the right track when we are being bombarded with emails and phone calls wanting help. The last thing I am thinking about is the "heavy science" as I am running backwards up a hill watching my athletes complete a Hill session

------------------
Run easy, Run long

Richard99

351 posts since
Oct 25, 2004

181. Dec 1, 2007 1:46 PM

in response to: Richard99

Andy,

You've got so many different things all mixed in your last post it would be way too cumbersome to address them all. So I'll just stick to one.

quote:<HR>Originally posted by AndyHass:
Running faster requires more power, DUH. <HR>

Thank you for confirming this point.

You have also previously pointed out that improved running economy means the runner is now running faster without using more oxygen/energy.

Combining those 2 things you've told us tells us that the increased pace means power has increased but energy usage has stayed the same.

But you also said, "The laws of physics dictate that you can't magically create greater power without consuming more energy per unit time.", which appears to be at odds with what what you said above.

Man, physics is hard. Glad I studied physiology instead.

------------------
Richard
World's Fastest Slow Runner
www.powerrunning.com

AndyHass

1,385 posts since
Dec 14, 2007

182. Dec 26, 2007 7:54 AM

in response to: Richard99

"You've got so many different things all mixed in your last post it would be way too cumbersome to address them all. So I'll just stick to one."

Translation -- You've got me over a barrel, so I will just ignore the facts I can't think of a way to refute.

"Running faster requires more power, DUH".
"Thank you for confirming this point."

That was never a debate.

"You have also previously pointed out that improved running economy means the runner is now running faster without using more oxygen/energy. "

Duh.

"Combining those 2 things you've told us tells us that the increased pace means power has increased but energy usage has stayed the same. "

No, no, NO. Power in the horizontal direction has increased. Energy usage in the horizontal direction has stayed the same (assuming no change in efficiency, which is in the real world not likely) because P = W/T and T is smaller at an increased pace. When you say "energy" you really mean "total energy" but when you say "power", you only consider "power applied in the horizontal direction". Because I have you over an unrefutable barrel on your lack of understanding this simply concept central to the argument here, you simply ignored this part of my post.

"But you also said, "The laws of physics dictate that you can't magically create greater power without consuming more energy per unit time.", which appears to be at odds with what what you said above." "

This was addressed in my previous post and is completely consisent if you are intelligent enough to understand total power output vs power output in a specified direction.

"Man, physics is hard. Glad I studied physiology instead."

Physics is part of physiology, as is statistics. Too bad you apparently didn't study any of it too hard.

While you're at it, address my last question that you dodged. Also address the fact that power output is NOT increasing overall, only in the desired direction and, as far as efficiency and economy (the topic, by the way) is concerned, is wholly explained by transfer of power wasted in non-horizontal movement into horizontal movement.

http://This message has been edited by AndyHass (edited Dec-01-2007).

bigapplepie

2,636 posts since
Dec 14, 2007

183. Dec 1, 2007 3:59 PM

in response to: Richard99

quote:<HR>Originally posted by AndyHass:

Dick, you use "total output of power by the muscles" and "power output applied to the ground to propel in the horizontal direction" interchangeably. For someone who claims to be some sort of physiology guru, this is a terribly simple concept that you should understand in your sleep.

Total power output by the running muscles = A(Horizontal power) + B(vertical power) + C(energy lost to heat that could have been power) +D(muscle oscillation power) + E + F + etc.

Any increase in efficiency, defined as energy lost to the none-desired variables (all but A) could be applied to A to increase pace without any increase in total energy usage. As I said, the fact that it takes more power to run at a faster pace(force)*D,(distance) so P = (F*D)/T. If you move X mass Y feet, F*D will stay the same but T will decrease because you're covering D faster. Decreasing mass helps this equation since W for given D would be lower as less F would be required to move the mass.
<HR>

Thanks Andy.

Richard99

351 posts since
Oct 25, 2004

184. Dec 26, 2007 7:54 AM

in response to: Richard99

Andy,

You're a whiz at physics. Thanks so much for your physics contribution to this thread.

quote:<HR>...power output is NOT increasing overall, only in the desired direction and, as far as efficiency and economy is concerned, is wholly explained by transfer of power wasted in non-horizontal movement into horizontal movement.<HR>

I understand the essence of your argument is that you believe increased efficiency fully explains the increased power output with no change in energy usage that results from improved running economy (assuming no change in body weight).

(Despite your attacks to the contrary, I actually do have some understanding of efficiency - see my post on page 2 and you will see efficiency is the first reason I gave explaining improved running economy, though your description/explanation of increased efficiency was certainly better than mine.)

We are in agreement that increased efficiency is one of explanation for improved running economy. Changes in body weight is another. Where we appear to differ is that I do not believe improved efficiency fully explains improved running economy. I suggest there is a third reason for improved running economy - namely increased ability of the muscle fibers to produce force.

------------------
Richard
World's Fastest Slow Runner
www.powerrunning.com[/URL" target="_blank">

http://This message has been edited by Richard99 (edited Dec-01-2007).

bigapplepie

2,636 posts since
Dec 14, 2007

185. Dec 1, 2007 6:44 PM

in response to: Richard99

quote:<HR>Originally posted by Richard99:
I suggest there is a third reason for improved running economy - namely increased ability of the muscle fibers to produce force.

<HR>

Richard
Does this reason involve bringing resistance to the leg muscles to develop muscle fibers aka you can develop more leg power by using resistance training?

Richard99

351 posts since
Oct 25, 2004

186. Dec 26, 2007 7:54 AM

in response to: Richard99

quote:<HR>Originally posted by bigapplepie:

Does this reason involve bringing resistance to the leg muscles to develop muscle fibers aka you can develop more leg power by using resistance training?<HR>

bigappliepie,

Resistance training does increase leg power, but it's not the only way. Studies have shown that running causes significant increases in muscle power. For example, a study on adaptations to marathon training showed absolute muscle power increased 50% and relative power increased 100% Other studies have shown that slow twitch fibers increase their rate of contraction as much as 20%. And, of course, muscles also get stronger (more forceful contractions). All three of these combine to increase the muscles ability to generate force.

------------------
Richard
World's Fastest Slow Runner
www.powerrunning.com[/URL" target="_blank">

http://This message has been edited by Richard99 (edited Dec-01-2007).

tigger077

691 posts since
Nov 19, 1999

187. Dec 1, 2007 7:12 PM

in response to: Richard99

For a first pass power output estimate one can ignore all but the horizontal component of energy. I would guess the others are so small as to be be considered negligible, however the rotational energy of one's legs might be significant enough to require a calculation, or to be included as a fudge factor. I suspect this component is subject to large improvement over time due to better posture...driving the heels up to your butt and reducing angular momentum to a minimum, rather than letting legs trail behind stiff legged style and then rotating the entire mass forward for another stride.

Efficiency can be measured by dividing power output by power input....a fairly typical calculation for engines or motors. After all, isn't that what the human body really is when running? An engine fuelled by glucose!

walrusgod

181 posts since
Dec 14, 2007

188. Dec 1, 2007 7:20 PM

in response to: Richard99

ive joined this thread quite late so ill read through it all later ( i have mock exams next week and its quarter 1 in the morning sunday now).

id say your genetics/phenotype is the biggest factor in this.

look at black marathon runners lower legs and compare them to most white peoples (and any other race's) lower legs. long achilles so, a much more efficient spring. i read somewhere that every 1cm extra length above average resulted in something like a 10% increase in efficiency. they have very thin lower legs too and relatively small feet, so less weight at the end of the lever.

having your feet not move very high above the ground is not efficient. the leg should fold so that the lever of your leg is much smaller so your hip flexors dont have to work as hard.

also things like leg length ratios, narrow hips etc will impact on efficiency.

bigapplepie

2,636 posts since
Dec 14, 2007

189. Dec 1, 2007 9:00 PM

in response to: Richard99

quote:<HR>Originally posted by walrusgod:
ive joined this thread quite late so ill read through it all later ( i have mock exams next week and its quarter 1 in the morning sunday now).

id say your genetics/phenotype is the biggest factor in this.

look at black marathon runners lower legs and compare them to most white peoples (and any other race's) lower legs. long achilles so, a much more efficient spring. i read somewhere that every 1cm extra length above average resulted in something like a 10% increase in efficiency. they have very thin lower legs too and relatively small feet, so less weight at the end of the lever.

having your feet not move very high above the ground is not efficient. the leg should fold so that the lever of your leg is much smaller so your hip flexors dont have to work as hard.

also things like leg length ratios, narrow hips etc will impact on efficiency.<HR>

So black marathon runners are genetically better than white marathon runners? That was a whole previous Richard thread. And, its not true.

Abadabajev

231 posts since
Oct 4, 1999

190. Dec 1, 2007 9:04 PM

in response to: Richard99

And i thought running was simple.

Increased efficiency is burning the same amount of energy as before but doing more work now.

Running faster is not simply a power variable. Everyone is forgetting strength.

so the new formula is

speed = strength + power

power is of course force x distance over time

ok back to my vodka

bigapplepie

2,636 posts since
Dec 14, 2007

191. Dec 1, 2007 9:07 PM

in response to: Richard99

quote:<HR>Originally posted by Richard99:
bigappliepie,

Resistance training does increase leg power, but it's not the only way. Studies have shown that running causes significant increases in muscle power. For example, a study on adaptations to marathon training showed absolute muscle power increased 50% and relative power increased 100% Other studies have shown that slow twitch fibers increase their rate of contraction as much as 20%. And, of course, muscles also get stronger (more forceful contractions). All three of these combine to increase the muscles ability to generate force.

<HR>

So basically you agree with Lydiard that "its important to develop leg power, flexibility and an economical running style" so that "the runner can run at relatively the same speed more economically".

AndyHass

1,385 posts since
Dec 14, 2007

192. Dec 1, 2007 9:18 PM

in response to: Richard99

Dick, we are in agreement about nothing. What you said, and what I said, are completely different. This is your typical attempt to pretend like we reached the same conclusion when nothing is further from the truth.

Unless you are admitting you were wrong, in which case, you should say so explicity.

"I suggest there is a third reason for improved running economy - namely increased ability of the muscle fibers to produce force."

You can suggest anything you want, but unless you can show that they do so without an increase in energy consumption, this has absolutely nothing to do with economy/efficiency.

Richard99

351 posts since
Oct 25, 2004

193. Dec 1, 2007 9:49 PM

in response to: Richard99

quote:<HR>Originally posted by AndyHass:
we are in agreement about nothing. <HR>

AndyDick,

Man, that is funny! Even when we agree you are so focused on disagreeing with me that you claim the areas where we agree are disagreements.

------------------
Richard
World's Fastest Slow Runner
www.powerrunning.com

IceStorm213

354 posts since
Nov 1, 2005

194. Dec 2, 2007 8:14 AM

in response to: Richard99

quote:<HR>Originally posted by Richard99:
Andy,

You've got so many different things all mixed in your last post it would be way too cumbersome to address them all. So I'll just stick to one.

Thank you for confirming this point.

You have also previously pointed out that improved running economy means the runner is now running faster without using more oxygen/energy.

Combining those 2 things you've told us tells us that the increased pace means power has increased but energy usage has stayed the same.

But you also said, "The laws of physics dictate that you can't magically create greater power without consuming more energy per unit time.", which appears to be at odds with what what you said above.

Man, physics is hard. Glad I studied physiology instead.

<HR>

Andy, consider yourself added to the long list of people who just don't "understand" poor Dick (and what a poor Dick he is)..

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