Running too many miles on the wrong surfaces can lead to running injuries. Alternatively, varying running surfaces can provide some very important benefits, including strengthening muscles, ligaments, and tendons, as well as aiding in the prevention of repetitive strain injuries and muscle imbalances.. The three most important points about running surfaces are:
- Running all your mileage on cambered roads can (and probably will) eventually lead to injury.
Because I had read that sidewalks were 40% to 60% harder than the asphalt used in most road base, I previously tried to avoid running on sidewalks. However, I recently read that the camber on most roadways can be as bad if not worse than the impact from a hard running surface. That's because as you run facing traffic, one leg is always landing uphill of another.
The March 2010 issue of Runner's World had an article by Amby Burfoot dealing with injury prevention. The article was titled "The Laws of Perpetual Motion". One of the laws was Run on a Level Surface. Here's an excerpt: "No doubt you always run on the left side of the road facing traffic. That's good for safety reasons. But it also gives you a functional leg length discrepancy, since your left foot hits the road lower on the slope than your right foot. You're also placing your left foot on a slant that tends to limit healthy pronation, and your right foot in a position that encourages overpronation. And you're doing this - running in an unbalanced way - 160 to 180 strides per minute for mile after mile, day after day, week after week."
Since there are advantages/disadvantages to each, what did I decide to do? I alternate between sidewalks, roads, and trails. Even though some sidewalks are cambered, you will generally return the way you came. This gives each leg equal time on the uphill part of the slant. With roads, that's not an option, because pedestrians and runners should run/walk facing traffic at the far edge of the road. That means the same leg is on the uphill side of the slant on the return route.
- Varying your running surfaces/routes may help to prevent repetitive motion injuries. When I checked into various training programs, some of them ran the same route week after week. It made logistics easier with a group of people, but it's not ideal. Why? Experts say that your muscles, ligaments, tendons have "memory". If you're continually moving your body in the same way (as would occur with running the same route week after week), you're more likely to have repetitive strain injuries than a runner who varies his routes. By varying your routes, your feet, ankles, legs perform many different movements adjusting to varying surfaces.
- Trail running can provide some important benefits, but be careful. "While road running generally provides a very uniform and stable surface, on the trail things are generally very uneven, with twists and turns, rocks and roots and frequent ups and downs...This kind of running with constantly changing conditions promotes the development of a very flexible and reactive system of body movements and trains your neuromuscular system to be ready for every kind of situation you might encounter...On the road...you end up with what you might call very linear development of your muscles and connective tissues. You will get very strong while moving directly straight ahead, but you will not be conditioned by absorb the impact of an unexpected misstep caused by a pothole, a branch in the road or even loose rocks...By teaching the body, legs, and feet to land on the ground at any angle, position, pitch or consistency, trail running builds the comprehensive strength that will help keep you injury free."*2 When I first started trail running, I twisted an ankle by tripping on a tree root. Running at a slower pace, working into trail running gradually (e.g. by starting out on non-technical trails), and being very aware of where your feet are landing are good tips for helping to prevent trail running mishaps.
|1||Sand||Extremely soft, very low impact stress, motion variability.||Not as much elastic recoil energy from footstrike as harder surface. Requires balance.|
|2||Grass||Soft, low impact stress, motion variability.||Not as much elastic recoil energy from footstrike as harder surface. Requires balance.Hidden hazards in taller grass (e.g. rabbit/gopher holes, rocks, glass).|
|3||Rubber (e.g. track)||Spongy feel, medium impact stress.||This is a great option, especially if you can find a rubber surfaces that isn't a circular track (e.g. part of Katy Trail in Dallas). Otherwise, continually doing circles on a track can lead to some of the same issues as a cambered road. I alternate directions halfway through if I'm using a circular track.|
|4||Dirt (e.g. trails)||Lower impact stress than crushed rock/concrete. Provides great motion variability. Great option for putting in the miles without all the pounding. Packed dirt on a groomed trail provides the softer surface with fairly good elastic recoil but not as much motion variability as on a technical (non-groomed) trail. Trail running leads to a more well-rounded development of your muscles, ligaments, tendons, and joints.*2||Pretty good elastic recoil but not as much as on concrete/asphalt. Usually not an option for a while after a hard rain. Also craters/holes/trenches from rain runoff if not well maintained. Technical trails usually have obstacles, drop-offs, roots, and rocks but provide the most motion variability and balance training.|
|5||Cinder/Crushed Rock (e.g. man made trails)||Softer than asphalt/concrete and usually more groomed than dirt trails. Not as susceptible to rain problems, but larger rocks can get stuck in tread of shoes.||Good elastic recoil, but the non-packed surface can result in some slippage on footstrike/pushoff.|
|6||Asphalt (e.g. road)||Supposedly 40% to 60% softer than concrete. Great availability and variability as far as distance and elevation. Due to a greater number of roads than trails, it's generally easier to find a road with the elevation profile of an upcoming road race than it is to find a trail with that elevation profile.||Safety concerns of sharing the road with cars. Cambered surface is not ideal for reasons mentioned above. Road that aren't well maintained (e.g. potholes) can be a hazard.|
|7||Concrete (e.g. sidewalk)||Lots of elastic recoil due to hardness of surface. Sidewalks provide safety from motorized vehicles (usually). If they are cambered, you can give each leg equal time on the upper slope.||One of the hardest surfaces. If in a neighborhood, there are usually lots of step ups/step downs on cross streets and some are not well maintained. Most of the park sidewalks I frequent are very well maintained. I can't say the same for many of the ones alongisde city streets. It's also difficult to find a continuous section of sidewalk over 7 miles or so. Many park paths are 3-5 miles at the most.|
*1 Boston Marathon Medical Directors: Pierre d'Hemecourt, MD (Co-Medical Director), Sophia Dyer, MD (Co-Medical Director), Aaron Baggish, MD
*2 Dr. Nicholas Romanov's Pose Method of Running