Running on concrete

Same here, I don't have the luxury to run on long trails unless I want to do endless 2mile loops  and I don't have the time nor means to get to a place where these trails are. 

So I run mostly on hard surfaces also. Not saying its good or bad, but then again most road races are on hard surfaces too (out of necessity of course, not by design).

Having said that, when I go for longer distances I get to a part where there is dirt and grass and gravel and I definitely try to run as much as I can on that when it presents itself.

Two weeks ago I ran on a treadmill for the first time every probably, and when I got off of it after about a 30 min run my balance was waaaay off, and I was bouncing up and down walking around the gym. Not bad I guess but at least enjoyable for others I hope

I'm actually prone to twisting my ankles which the soft surface trails around me don't help a lot with. I'm always stepping in holes or tripping over tree roots. Maybe this concrete trail is a good compromise.

Now fingers crossed I'll be well enough to run again soon!

Ah I hadn't even thought about that. I have problems with that too sometimes. However, I've found running on wet dirt to be a good exercise on cadence as I have to take small quick steps so I don't slide or lose grip :D

Good luck on your injury and I hope you get to test out the concrete soon.

Yes Concrete Is the hardest and most potentally damaging surface to run on, but as most mentioned if you are not prone to lower leg  SF/ or shin splint  issues and are not running on it 5 time a week, it will be fine to run on, but it is a poor choice for a multi use pathway, Ashphalt would have been a better choice. personally I never run on Concrete sidewalks more then twice a week, any more and I can feel it start to stress my lower legs, if I can I will switch up with a run on trail, asphalt or on a rubberised or chip & dust track if I can get to one rather then going day after day on the concrete sidewalk.

I kind of thought this too. The trail is only 3 miles long for now, plans to expand but it will be a while. Anyway, in that 3 miles there are 4 10-12% up & down hills plus the debris all over from the trees. Cycling is pretty much a no go unless you want to risk taking out a walker on one of the downhills. Not much for multi use unless you run or walk as far as I can tell.

This is one of my favorite urban-running myths.

Yes - concrete is harder than asphalt which in turn is harder than packed dirt. But the difference in amount of deflection and cushioning between these surfaces is NEGLIGIBLE and makes no difference to runners.

In engineering terms, all these surfaces are significantly higher Yield Strength than a human foot (regardless whether its bare of shod in a running shoe). The human foot will deflect (or shoe rubber will compress) until its yield is equal to that for the material you are running on.

Unless you are a 500lb person with size 1 feet who pounds the ground with all his might there will be ZERO physical difference between running on concrete and asphalt and packed dirt.

Any difference felt is purely psychological.

*Note: running tracks made of fused rubber pellets, grass, and sand have different Yield Strength  and/or modulus of elasticity - but that's is a different story

Thanks Mark, couldn't have said it better myself - coming from an engineering background.

Ditto what others said about concrete hardness not being enough to notice.  I run barefoot or minimal and on concrete for about 75% of my runs (including the long ones) and I have no issues even though I was previously impact injury prone.  Your body can adjust if you let it.

Though it does sound like whomever planned that MUP probably didn't consult with the types of people who might actually be using it!

I'd like to modify my statement to read that concrete isn't noticeably harder than properly laid asphalt (like a road).  It is obviously significantly harder than soft dirt, grass or gravel.  

I also have noticed that when asphalt is just poorly poured over a gravel foundation in what looks like a totally half-assed attempt at 'paving' a trail, it also seems much softer than concrete to me.  I'm not a civil engineer, but I suspect that what is under the asphalt probably has an effect on it's perceived hardness as well.

Thank you for posting this.  You saved me the sermon.  This myth is sooo pervasive however.  As is the tires popping from the difference between night and day temps.

Deflection is the engineering term for movement or compression.  What this means is that the human foot/leg/muscle/joints etc... plus the shoe soles are much more compliant than concrete or asphalt.

When you push on something it pushes back.  The strong of the two materials will deflect less than the softer of the materials.  Think about throwing a water balloon against a wall.  The balloon deflects a lot.  The wall deflects almost nothing at all.  This is because the wall has a MUCH higher yield strength (more accurately a higher Young's Modulus) than the water balloon.

The Young's Modulus of concrete and asphalt are 1000s of times higher than your foots, shoes, legs, joints and all the things connected to your body.  So while asphalt might deflect (give) a little bit more than concrete the difference is so infinitesimally small compared to how much your body deflects that it makes no difference. 

The difference is purely psychological. That being said you should do what makes you happy.

But physics doesn't lie.

Here is an abstract on a study done on the subject: http://www.ncbi.nlm.nih.gov/pubmed/2946394?dopt=Abstract

Exactly.  No difference.  I use my trusty hammer test.  I take my hammer to the concrete trail and pound it as hard as I can.  Note the vibration and indention in the concrete.  Do the same on asphalt.  No difference.

I note an air of sarcasm.  It is true that asphalt is "softer" than concrete.  However asphalt is so MANY MANY time harder than your shoes, legs, joints, feet etc.. that the asphalt defects more than the concrete, an amount that is almost immeasurable. Therefore all of the deflection has to be on the opposite side of the road (into you).  Therefore, essentially no difference.

The knee specialist doc I work with  is a 5 x Ironman.   He would never routinely  run on concrete, only on rare instances.

The proof you might be requesting might not show up right away,  but in 3-5 yrs from now. Takes a while for the cartilage to wear down.

I love how people think anecdotal evidence trumps physics. So a person who never runs on concrete has never had knee issues.  And that proves what exactly?

There are LOTS of other possibilities as to why running on concrete might be different than asphalt (most sidewalks are concrete and you often have to step up up on curbs or move side to side to avoid cracks etc...).  However "softness" of the materials is not one of them.  Don't like concrete.  Then don't run on it.  But also don't spread misinformation.

But don't take my word for it... http://www.nytimes.com/2011/07/19/health/nutrition/19best.html

I run on whatever surface happens to be beneath my feet. Asphalt and concrete feel the same. I prefer running on asphalt for psychological reasons, like it's the same surface I race on (yay!) and I associate concrete with running on sidewalks (boo!).

As was pointed out using logic and supporting data, feet (and running shoes) are softer than the surface they are striking and will deflect accordingly. Assuming you replace shoes when needed, neither one is going to cause more wear and tear on your body.