Many runners gravitate toward "softer" asphalt and away from concrete. But I've yet to see any proof that asphalt is kinder to the human body, especially one wearing cushioned running shoes.
Many runners gravitate toward "softer" asphalt and away from concrete. But I've yet to see any proof that asphalt is kinder to the human body, especially one wearing cushioned running shoes.
I wanted to find this out as well. If I remember correctly I swear I read some where that concrete is 10 times harder then asphalt. . . I need to know is this true?
Pavement according to that article was 3-4x worse than grass, and Cement is 10x worse than asphalt.
That was according to the article
The proof for me is that I can feel the differnce over the course of a long run.
When I was a young man, that was not so much the case, as the elasticity of the body was strong. Now that I'm an old geezer, I most definitely feel the hardness of concrete taking a greater toll on the body when compared to asphalt. I know that that is not scientific proof, but to paraphase someone else, "Go asphalt, young man, go asphalt."
I've always thought this was bunk myself. Concrete probably compresses 1 micron when your foot strikes it and asphalt compresses 5 microns. Either way, there's virtually no "give" in either of them. On either one, most of the energy is dissipated through your shoes and body.
It's like asking if getting hit with a wooden bat or an aluminum bat would hurt worse. Does it really f'ing matter?
This is not just bunk. It has been proven. When your foot strikes the ground, concrete does not give any. Concrete is very strong with steel inside to increase the strength. Asphalt gives quite a bit & therefore, the full force of your foot striking the ground is not being distributed at all with concrete. Your legs bear almost all of the impact. On the other hand, asphalt absorbs some of the blow. Being in construction, I know this to be true. And I believe, from experience, landing on concrete would probably be in the neighborhood of 10 times harder than landing on asphalt. A huge difference, that definitely should be taken into account if you want a long running career.
Wrong wrote:
This is not just bunk. It has been proven. When your foot strikes the ground, concrete does not give any. Concrete is very strong with steel inside to increase the strength. Asphalt gives quite a bit & therefore, the full force of your foot striking the ground is not being distributed at all with concrete. Your legs bear almost all of the impact. On the other hand, asphalt absorbs some of the blow. Being in construction, I know this to be true. And I believe, from experience, landing on concrete would probably be in the neighborhood of 10 times harder than landing on asphalt. A huge difference, that definitely should be taken into account if you want a long running career.
I understand that concrete is harder. But at some point, it doesn't make a significant difference anymore. For example, you say concrete doesn't give any. So if there was a substance that was 10 times harder than concrete, it wouldn't make any difference, because concrete already doesn't give any.
My point is, I don't think asphalt gives "any". Meaning, I don't think it absorbs much energy from a foot strike. Especially if it's cold asphalt. Sure, on a 100 degree day, when the asphalt is softened up a bit, it's probably significantly better to run on. But in the morning, or a cool, cloudy day, I don't think it makes a difference.
That being said, my argument is all speculation and I'd love to see a scientific study. And I'd like to see it take the temperature of the asphalt into consideration. So I'm with the original poster. Does anyone know of a study on this subject? One that doesn't just calculate the "hardness" of the surface, but calculates the energy dissipated into the surface of a impact comparable to an average runner's footstrike. Heck, they could even do it for different shoe types too. If such a study doesn't exist, I think I'm going to write a proposal for a research grant on this sh!t.
Total tangent, has anyone ever applied for a research grant? A freshman at my university once got $60k for himself because he wrote a proposal to try to develop a chemical that you could take that would quickly counteract alcohol. He blew the money and didn't come up with anything. But the government is always giving away research grants like this.
Somebody told me once that concrete is 7 times harder than asphault...
here are some studies:
Title: Surface effects on ground reaction forces and lower extremity kinematics in running
Author(s): Dixon SJ, Collop AC, Batt ME
Source: MEDICINE AND SCIENCE IN SPORTS AND EXERCISE 32 (11): 1919-1926 NOV 2000
Abstract: Introduction: Although running surface stiffness has been associated with overuse injuries, all evidence to support this suggestion has been circumstantial. In the present study, the biomechanical response of heel-toe runners to changes in running surface has been investigated. Methods: Six heel-toe runners performed shod running trials over three surfaces: a conventional asphalt surface, a new rubber-modified asphalt surface, and an acrylic sports surface. The surfaces were categorised according to impact absorbing ability using standard impact test procedures (BS 7044). Results: The rubber-modified asphalt was found to exhibit the greatest amount of mechanical impact absorption, and the conventional asphalt thr least. The comparison of peak impact force values across surfaces for the group of subjects demonstrated no significant differences in magnitude of force. However, a significant reduction in loading rate of peak impact force was detected for the rubber-modified surface compared with conventional asphalt (P < 0.1). Although analysis of group data revealed no significant differences in kinematic variables when running on the different surfaces, a varied response to surface manipulation among runners was demonstrated, with marked differences in initial joint angles, peak joint angles, and peak joint angular velocities being observed. Discussion: For some subjects, the maintenance of similar peak impact forces for different running surfaces was explained by observed kinematic adjustments. For example, when running on the surface providing the least impact absorption, an increased initial knee flexion was observed for some subjects, suggesting an increased lower extremity compliance. However, for some subjects, sagittal plane kinematic data were not sufficient for the explanation of peak impact force results. It appears that the mechanism of adaptation varies among runners, highlighting the requirement of individual subject analyses.
this is an old one, but it did compare asphalt and concrete and grass.
FEEHERY RV. SPORTS MED 3 : 649 1986
As I recall there was no diff in the forces measured. Seems odd, the thinking was that people adapt so as to NOT let the forces go too high on concrete.
Just out of curiosity, how many of you guys know how "hardness" is measured? If you don't know, go ask a civil or mechanical engineer. You might be surprised and if you think about it, it might shed a little light on whether or not increased hardness directly results in similar increases in impact forces as felt by a runner. Just because a surface is 10 times harder doesn't mean that your bones and joints are experiencing 10 times the force. Mind you, I'm not saying there's never a difference, it just may not be as much as you think. I can say from personal experience that recently paved asphalt roads seem a little more compliant to me than old ones (but maybe that's just in my head, I don't know).
A thought experiment: Supposing concrete is 10X harder than asphalt, imagine that you were running along and tripped. Do you think that your injuries would be 10X worse if you fell on concrete than asphalt? I think both of them would hurt quite a bit. I imagine the difference would be akin to getting bit by an 80 pound German Shepard vs. a 70 pounder. I think there are a great many other factors that are more important. For example, perhaps the most direct way for the casual jogger to reduce impact forces is to lose some weight.
Rodger Kram wrote:
Discussion: For some subjects, the maintenance of similar peak impact forces for different running surfaces was explained by observed kinematic adjustments. For example, when running on the surface providing the least impact absorption, an increased initial knee flexion was observed for some subjects, suggesting an increased lower extremity compliance. However, for some subjects, sagittal plane kinematic data were not sufficient for the explanation of peak impact force results. It appears that the mechanism of adaptation varies among runners, highlighting the requirement of individual subject analyses.
This deserves re-emphasis. You can't look at a surface independent of the human body. There's an adaptive strategy that takes place, depending on the surface, to help attenuate ground reaction force.
I agree that asphalt is pretty damn hard and certainly not much softer than concrete from a runners perspective.
Having said that, if someone gave you a pick and offered you a choice between breaking up an 8 by 8 ft section of asphalt, or an 8 by 8 section of concrete, which would you rather tackle?
rick wrote:
I agree that asphalt is pretty damn hard and certainly not much softer than concrete from a runners perspective.
Having said that, if someone gave you a pick and offered you a choice between breaking up an 8 by 8 ft section of asphalt, or an 8 by 8 section of concrete, which would you rather tackle?
Now this is a manual labor thread? With a proper sledge and assuming the concrete isn't riddled with rebar, I'd probably take the concrete. Harder to break up, but it wouldn't crumble as much, so it would probably be easier to extract. Plus, if you strike the concrete good with the sledge, it fractures pretty well because of the "hardness". Whereas if you have softer asphalt, your sledge might just make a perfectly round crater and not actually crack up the asphalt. Also, thickness is an important factor in this question. I wouldn't want to crack up anything thicker than 4"-6" of concrete, as I'm not even sure it would be possible with a sledge.
concrete = rigid pavement
asphalt = flexible pavment
The hardness varies depending on the mix design, but you get the point.
Okay, they're both hard, but if a concrete path is right next to an asphalt one, I think it's safe to say the asphalt would be the better choice. It may not help very much, but I'm sure it helps a little.
I prefer concrete. There's too much temperature change in asphalt and it makes the tires much slicker as the temp. rises. With concrete it's more uniform.
Many people think you lose a lot of time off the tires on concrete but that's not true. You're able to run more consistent lap times on concrete because with the heat not bothering the concrete, the car doesn't slide as much. Also, getting up in the marbles doesn't affect you as much on concrete.
Now, if you get to a place like Martinsville, that's a different matter. With concrete corners and asphalt straightaways you really have your hands full if you know what I mean!
Concrete 10 or 100 times harder it doesn't matter! Just learn to run efficiently at
! Find a pose instructor in your area to learn to run correctly and injury free, even on a surface harder than Ron Jeremy!
JHuffman
I lived in NYC until I went off to college, and I had a period where I would regularly do runs on sidewalks at night. It started to hurt, and eventually I could really tell the difference between the hardness of the street and of the sidewalk. The street was much more forgiving on my legs -- but by this point I was hypersensitive to it. Right now I run on both and I can't really tell the difference.
During summer asphalt has much more give than winter.
What Would Jeremy Do wrote:
Concrete 10 or 100 times harder it doesn't matter! Just learn to run efficiently at
http://www.posetech.com! Find a pose instructor in your area to learn to run correctly and injury free, even on a surface harder than Ron Jeremy!
JHuffman
I would recommend that you run on whichever feels more comfortable to you. As you so willingly pointed out efficient form is the most important thing regardless of whether you are running on asphalt,concrete,dirt,track,grass. And I strongly encourage every runner to go to
www.posetech.comand learn how to run more efficiently. Good day!