Ever wonder why so many people run in the parks, on dirt trails where it’s nice and soft, rather than that hard concrete we punish ourselves on during marathons? The answer is very simple: natural trail surfaces “give”; concrete does not.

As we all know too well, the legs, knees, and feet of a runner take on the full extent of impact trauma, shock absorption, and friction. Under ideal conditions, therefore, we look for surfaces that will absorb shock to the lower extremities while simultaneously providing energy return to the foot in a continued motion.

There are quite a number of surfaces one can run on artificial snow, asphalt, bark, carpet, cinders, clay, concrete, dirt, grass, hard synthetics, rock, sand, snow, and wood. In a report featured in 1983 in Athletic Purchasing and Facilities, John Sprague described 106 synthetic surfaces for sports.

At one point, you may have run on a majority of these surfaces. Which one did you like the best, and which surface gave you the best without injury? Which surface has the best efficiency, and yet lowers the risk for repeated trauma to legs, knees, and feet?

One frequently asked question is, “Should we run on a natural surface or a synthetic surface?”

I prefer more natural surfaces, but with a cushioned ride there is also a trade-off. Soft surfaces give great shock absorption and cut friction down tremendously, however they sacrifice stability of foot and body alignment. This can translate into excessive supination/pronation of the foot, which can develop into heel pain/plantar fasciitis, Achilles tendonitis, posterior tibial and peroneal tendonitis, ankle sprain, and overuse knee pain. How many times have you run on a nice soft grass/dirt running trail, and quickly caught yourself in a divot or chuck hole? I’m sure we’ve all experienced that at one time or another. I suffered an ankle sprain that took many months to recover from after my foot rolled off the asphalt trail at a golf course. I always advise friends and patients to watch where they are going when they run on soft surfaces, particularly if it is a new course or trail.

Soft surfaces often feel bouncy and seem to give us the energy return that makes a run enjoyable and less stressful on our legs. We usually complain less about our knees the next morning. The problem with dirt/gravel or grass/dirt trails is that our 5K, 10K, and marathons are rarely ever run on these surfaces, and so, while it may be a great training surface on which to avoid injury during long runs, it does not prepare our bodies for the upcoming stresses of the city streets we have to pound during the course of most marathons. I often advise my running patients that if they do not experience or train on some concrete and asphalt before the marathon, they will set themselves up for a potential stress fracture of the metatarsals or the tibial-fibula (shins).

So what’s a good compromise? I like asphalt. In fact, I love asphalt! I can immediately tell the difference between concrete and asphalt during the marathon. After running on asphalt, my legs shock and strain, whereas running on concrete batters my calves, hamstrings, and knees. (Of course, if you think these surfaces are tough, try running across steel/concrete bridges at the N.Y.C. Marathon. All the carpet in the world on that bridge doesn’t soften the worst surface I’ve ever run on.)

So if concrete is too hard, and grass/dirt is too soft, what is one to do?
You could choose intermediate surfaces that don’t expose you to harmful injury. Indoor tracks are a good example. Indoor tracks offer wood surfaces, some with air suspension, and synthetic surfaces, many very well padded and rubbery, with excellent shock absorption properties and energy return. I have always enjoyed running on these indoor track surfaces during thunderstorms, heat, and inclement weather. I also like to run on these during rehabilitation from leg or foot injuries. They are excellent to start a walk/run program on, limiting the shock and friction which can lead to a recurrence of the initial injury.

And what about you winter runners? In the Panhandle and North Texas, snow is not unheard of, and many Lone Star runners like to travel to ski country. On my honeymoon in Austria, after skiing and before dinner, I would run around the Lake Zell am See, with flurries in the night sky, reflected by the lights, and listen to the church of the snow beneath my feet. I could feel the difference immediately. It was soft yet stable (except for the slide), and was actually fun to run on. Due to friction, you had to use the hamstrings a lot more to prevent hydroplaning. I’ve run on snow in Colorado, New England, and New York in the winter months, and it is quite and experience. Snow cuts impact shock tremendously, but you do not have to avoid falls.

So when pondering whether to run on an asphalt street or new development concrete, consider your past experiences, lower leg/foot health status (injuries), the distance and speed you are going to run, and then decide if the park with its soft surface is better or not. Also, pay attention to your shoes, keeping alert to the possibility of age and E.V.A. breakdown. When running the streets, good shoes with good shock absorption is a must.

Dr. Jeffrey Ross is a Podiatrist, M.D. in private practice in Houston, TX. To book an appointment with Dr. Ross or find out about his services he can be reached at 713.791.9521.