This question often pops up on discussion forums and in comments about articles. It seems to be an age-old question from runners who are concerned about the health of their legs and feet. Those of us who put in many miles a week probably should question what the ground beneath us is doing to our joints, muscles, and tendons. But, do we concern ourselves too much by these sorts of things?
In an article
by Marc Bloom and Steve Smythe from Runner’s World
, they break down the many surfaces on which we run. You see, it’s more than just dirt and pavement; we may run on Grass, Woodland Trails, Earth, Cinders, Synthetic Track, Treadmills (dreadmills), Asphalt, Sand, Concrete, or Snow. I’m sure that there are more surfaces as well. So which is best? According to their findings (or opinions), grass is the optimal surface for running. While grassland may be uneven and have hidden dangers, if you find an even flat stretch of it, you should take advantage. Grass offers soft and easy impact on your legs, while letting your muscles put in some extra work. You may even see your muscles gain strength, giving you an added edge when you return to the pavement.
At the bottom of their list: Snow & Concrete. If you live in the North, you know about snow. If you reside in a big city, you will certainly understand pavement. If you live in a city up North, well… that’s a double whammy. Don’t get too down on yourself though; there are many benefits to both snow and concrete.
It is pretty obvious that snow presents potential dangers. But, fresh snow can offer a beautiful escape from the monotony that life often presents. With its beauty, you can get lost in your run, taking in the landscape around you. [Just be careful to trace your footsteps back to where you started] Snow also forces us to slow down, helping our muscles to recover from any injuries that we may have developed. Often times, our bodies may be experiencing trouble before we even know it.
Concrete, which consists of sidewalks, (most) roadways, parking lots, etc., is probably the most questioned surface we trek. There seems to be a little confusion between asphalt and concrete though. To clear things up, both are formed with an aggregate (a whole formed by combining several elements) mixture. The binders used in these mixtures are what set them apart. Asphalt uses natural deposits or crude oil, while concrete uses a cement binder. Many surfaces today use a mix of the two, or “asphalt concrete.” Don’t get all caught up in the lingo though, both surfaces are similar as far as impact on the legs and feet go. For the purposes of this article, we will refer to both as “pavement.”
Pavement is primarily made up of crushed rocks which are bonded together. This provides a hard, structurally sound, surface for runners. Because of constant construction, and the necessity of roadways, runners can typically depend on pavement as their go-to source for a route. If your city has a greenway or long even sidewalks, you can use them to avoid the traffic of motorists. When runners start reaching half-marathon
distances, they tend to start using roads more often. When training for a marathon, you should be reaching 20+ miles on your longest runs, thus making roads and streets the ultimate training courses. Besides, your race will most likely be taking place on a roadway.
So, how does pavement affect our bodies? In Paul Ingraham’s article, Always Running the Same Way
, he explains that the human body has the ability to take on many different running surfaces, including but not limited to, concrete and dirt. He states that, “Although most runners believe that the rigidity of concrete is the main problem, it may be that the continuity of the surface is just as bad or worse … Not only is the stress of impact exaggerated by the hard surface, but it is also repeated excessively because the mechanics of every step are exactly the same.” Worth noting, is that most running injuries are repetitive strain injuries. Running on the same surface, whether it’s sand or stone, will cause you to continually work the same muscles and stress the same joints. The most common running ailments from repeatedly running on concrete and asphalt are shin splints; medial tibial stress syndrome, compartment syndrome, and stress fractures. As Paul mentions, our anatomy is designed for shock absorption, but we have our limits. Highly repetitive pounding on a hard surface can simply crack the tibia (stress fracture).
[Another factor in the running-injury equation is elevation. Our legs use different muscles for going uphill than they do going downhill. If you live near the East Coast, you may be running on flat surfaces all year long. This is another example of repetitive running motion]
At this point, you may be wondering, “What are the alternatives? Should I give up pavement all together?” Some runners would suggest that you get off of the pavement for good. I recommend that runners try and vary their playing fields. Often times, after many injuries, runners will make the decision to do all off-road running. This is fine, if your off-road course has fluctuating surfaces, including gravel, dirt, sand, and clay. Unfortunately, we don’t all have access to such a course. So, remember that if you decide to go all trail running, it may not be adequate. It may be soft, but it is still “same-surface” running. Try and switch up your surfaces regularly and explore new options.
What is your favorite running surface? Do you prefer dirt, sand, gravel, concrete? Have you had any injuries from running on pavement? Comment below and let me know. I look forward to hearing from your experiences.