Well technically it is, but it does not make any difference when running. Saw a couple more people complain about having to run on a concrete sidewalk today. This is a running myth that just keeps getting passed along. Your legs cannot tell the difference.
Think about it. Both concrete and asphalt are both rock hard. Your feet are padded and your shoes are padded. This large amount of padding makes the differences between the two surfaces negligible.
Take a hammer and whack both surfaces. You will definately notice a difference. But that is not how it works with running. Put one of your shoes on the road and one on the sidewalk. Hit both with your hammer. Not a chance you will be able to tell the difference.
But the asphalt doesn’t have seams, ledges, edges and cracks for us old guys to trip on. Therefore I will stay on the softer, smoother surface when possible.
Well technically it is, but it does not make any difference when running. Saw a couple more people complain about having to run on a concrete sidewalk today. This is a running myth that just keeps getting passed along. Your legs cannot tell the difference.
Think about it. Both concrete and asphalt are both rock hard. Your feet are padded and your shoes are padded. This large amount of padding makes the differences between the two surfaces negligible.
Take a hammer and whack both surfaces. You will definately notice a difference. But that is not how it works with running. Put one of your shoes on the road and one on the sidewalk. Hit both with your hammer. Not a chance you will be able to tell the difference.
Myth busted. Stop complaining.
I’m not buying your myth busting “yet”. Give me some more data on how impulse forces are dissipated in concrete versus pavement with graphs and frequency domain plots etc and then I’ll buy in. If you can provide that, I am listening…until then, I’m running on pavement over concrete when I have the option.
This is a running myth that just keeps getting passed along. Your legs cannot tell the difference.
Hardly. When I do a run with a lot of concrete, my lower back and quads hurt. That’s my n=1. It’s not a myth for me but a fact. It’s always been that way for me in my 29 years of competitive running. Your results may vary.
…not so fast. You can’t just take the modulus of elasticity of different materials and assume that how they deform under an impulse force is the only thing at play. Given that neither pavement nor concrete is deforming undering the impulse force of a runner landing, I THINK you have to look at how that impulse force is dissipated under the foot and what percent of the energy from the runner landing bounces back at the runner vs gradually dissipating in the material via a shockwave that should eventually dissipate into heat. I am not sure that the puny diff in Young’s modulus between the materials actually tells us what happens to the impulse force. Clearly, none of us are “deforming” the material under us.
Now, I took my last mechanics course in December of 1985 and then went over to the electrical side of the world, so I might be wrong. We need some more recent mechanical engineering or civ eng grads to shed some light on where Young’s Modulus comes into play here.
As you said, my knees are telling me something after 36 years as a competitive runner than the modulus of elastisity of pavement and concrete are not telling me. I THINK the link that you pointed us to is coming to an incorrect conclusion, assuming the deformation of the material tells the entire story…I don’t THINK so but glad to hear more.
Just about to say that this has been studied before and is easy to do. Force/pressure transducers are put in shoes, go run, record pressure values. Repeat with many different runners on many different surfaces. Data logged. Done.
Or … you can use a hammer I suppose. I’ve used a “hammer” on lots of other things - why not
This is n=1 and it could be entirely my imagination at work, but my legs feel significantly less beaten-up when I run on the road (asphalt) vs exactly the same route on the sidewalk (concrete).
Thanks, just looked at it. They claim no statistical difference between pavement and concrete. But how do we know that the mechanism they used to “measure” is precise enough and it was not in the measurement error. Our brains can detect 2-5% of anything (for example, Most of us can tell the diff when the wattage goes up from 250W to 255W and certainly to 262W). Our brains can detect a fairly minute acceleration of 2 cm/s^^2 (that one is from flight simulator design). Our brains can tell the difference between 90 second pace at the track and 92. Maybe our brains can detect more of a difference between concrete and pavement than the measurement apparatus could. Do these things have strain gauges in the insole that are deformed on impact, in which case a lot of it can blow up in smoke if you don’t have proper temperature compensation in the measurement mechanism anyway. If the diff is 2-5% and was not measureable by the device, then that is plenty.
What these studies may just be saying is that they were unable to accurately measure what the human brain can. Millions of runners are probably not that wrong. I’m betting that the means use to measure is more wrong than human feedback from the real world.
The stiffness has a pretty big impact on how force dissipates, but somebody with a better understanding of dynamic forces and how it’s relevant to running will have to chime because it’s above my pay grade.
From what I can gather, the elastic modulus of asphalt varies as a function of temperature. At 32 degrees it’s roughly the same as concrete, but at 70 degrees it’s an order of magnitude lower. If you’ve ever noticed that asphalt seems “softer” in the summer, this is probably why. It also explains why a motorcycle kickstand will dig into asphalt on a hot summer’s day.
I can’t verify this from a book because everything I have only includes building materials, but from a search it seems the compressive strength of asphalt is roughly 2.1 MPa which is only about 300 psi. That seems low to me, but it’s plausible. That would make the compressive strength of concrete an order of magnitude higher and would mean that asphalt would yield well before. I have my doubts that the pressure applied from running exceeds 300 psi, but if true that could be another relevant factor.
The “hammer test” is bunk. Besides, if you hit summer asphalt with a hammer (or even just drop something on it), you’ll see it deform; concrete doesn’t do that.
The above may or may not be relevant to running, but it’s clear that concrete is the stiffer material.
I did an independent test on this the other day. I closed my eyes and ran on either concrete or pavement to see if I could tell the difference. In both cases I ran into a parked car.
Pretty sure the OP is dead wrong here. Civil here, we actually had a professor address this issue during some lab testing. The differences are very minimal, but running on PCC bashes your legs more than AC. Not going into details because I’m pretty certain the OP is trolling. Avoid running on concrete when possible.
By all means, go into details. I’d be interested to know more about it. We learned about asphalt briefly in undergrad, but once I went into structures I forgot all about it. We won’t have any asphalt buildings anytime soon, so it’s off the radar in a structural curriculum. I chalked it up to the difference in stiffness, but that may not be entirely accurate.
Pretty sure the OP is dead wrong here. Civil here, we actually had a professor address this issue during some lab testing. The differences are very minimal, but running on PCC bashes your legs more than AC. Not going into details because I’m pretty certain the OP is trolling. Avoid running on concrete when possible.
No, please post the details and the data. Seriously.
When I searched for this topic online all I get is a bunch of, well I was told, and it is my understanding etc… I hate that, it tells me nothing. I want some facts.
I currently run on cement, asphalt and crusher dust and the one thing that I notice is how different my body reacts to the way my foots leaves the surface. Sticky asphalt holds my foot longer, and seems more variable. Crusher dust makes me slide around a bit more until I adapt. Concrete stays the same and my running gait, therefore isn’t as affected. But that is just my “feeling” and is not scientific.
