Concrete, Asphalt, Dirt Roads & Grass
What’s the best surface for running on? Well, it depends! The reason we need to consider different surfaces are because they vary significantly in “hardness” which affects 1) the impact to our bodies and 2) the energy loss or return as we run.
1) Running is always classified as a high impact sport but we can use a variety of surfaces to reduce that impact. Reduced impact means lowered risk of bone injury like stress fractures and stress reactions.
2) Softer surfaces absorb energy more than harder surfaces, in other words, softer surfaces are less responsive than harder surfaces. Runners want more responsive surfaces for running fast and hard surfaces return more energy from each step, allowing us to run faster.
Concrete
Concrete is the hardest surface commonly available for runners and offers the least shock absorption. Runners literally “pound the pavement.” Concrete absorbs significantly less energy than softer surfaces which means more energy return for the runner, and therefore faster times. Concrete is a great choice for anytime you want to maximize your speed, such as time trials, virtual races, and intense workouts.
Some running tracks are laid on top of concrete which makes them fast for races, but not ideal for frequent training or high volume workouts because they are so hard.
Asphalt
Like concrete, asphalt is quite responsive but in general it is slightly softer and easier on the body. Asphalt actually gets harder in cold temps so in the middle of winter it is not significantly softer than concrete. However, on a hot summer day asphalt is softer, offers better shock absorption and will run slower than concrete.
New asphalt is softer and absorbs shock better than old asphalt. (Fresh blacktop is my absolute favourite surface to run on, no doubt about it!)
Asphalt is ideal for long runs, lots of volume at an honest pace, and road workouts.
Dirt Roads
Dirt roads, crushed gravel, limestone, and the like are significantly softer and easier on the body than asphalt and concrete, but still quite responsive. I personally don’t experience a significant difference in my ability to run easy to moderate paces on dirt roads, however hard and fast paces are slightly more challenging on dirt roads.
Dirt roads absorb shock much better than concrete and asphalt, so more energy is lost with each step. Furthermore, on gravel or limestone or even dirt that isn’t super hard packed there is a tiny bit of slipping backward with each step which slows us down.
Dirt roads are ideal for long runs, longer tempo runs and general mileage. Dirt roads are a great choice for runners who are prone to stress injuries and for runners returning to fitness after a stress injury.
Grass
Grass (or artificial turf) is one of the softest feasible options for runners. Not all grass works well - if it’s too long the grass will hide holes or uneven ground which can be dangerous for runners. If accessible, turf and well groomed grass on soccer fields and golf courses are preferred. These surfaces are perfect for runners returning to run after a stress injury, and should always be prioritized before adding miles on asphalt or concrete.
Grass is very soft and therefore not very responsive. Grass is a slow surface for running! This is generally not an issue when the purpose is reduced impact and return from injury. Grass isn’t a good choice for runners wanting to maximize their speed on a given day.
Because grass is so soft, it is inherently less stable than harder surfaces. Running on grass requires more engagement of stabilizing muscles which may not need to do much work on hard surfaces, which means that grass running requires more muscular contribution than harder surfaces and is more fatiguing. Grass isn’t a good choice for a runner who is returning from an ankle injury. However, once the ankle is strong enough for running on stable surfaces, some running on turf or very well groomed grass could be incorporated into the training schedule as rehabilitation and conditioning to strengthen the lower legs and ankles.
Prepare for Your Purpose
It may seem smart to run exclusively on soft surfaces to reduce injury risk, but it’s important to run on harder surfaces if your goal race will be run on roads. On the other hand, if your race is to be held on trails, grass, or dirt roads, you will need to train on those surfaces.
Other Considerations
Pay attention to the crown or slope of the roads you run on. For safety, runners should run on sidewalks or on the left hand side of the road, facing oncoming traffic. However, a sloped surface or crowned road can cause problems with alignment of the hips since one leg will be higher than the other. Avoid running any significant distance on a sloped or crowned surface whenever possible. If not possible, spend extra time working mobility and rolling after your run, and pay attention to any asymmetries of tightness or soreness in the body.
Nicole Sifuentes is a full-time Running Coach for adults of all ages and abilities. She is a former professional runner and 2-time Olympian, and Certified Strength and Conditioning Specialist. Read more about her services, and schedule your free coaching consultation.