There’s something primal and satisfying about running on dirt. When you look up and see a trail extend into the trees or a dirt road wind out of sight, it’s easy to imagine yourself as a prehistoric human, proudly chasing down an antelope to feed your family. We instinctively feel that if something is natural, it must be better for us. Dirt and grass are more natural than concrete, but does running on soft surfaces prevent injury?
And hey, the Kenyans run on dirt roads – that must make it good…right?? Well, like most things in running, it’s just not that simple. The simple answer is “no.” The more interesting answer is “it depends on your body but probably doesn’t make a huge difference either way.”
Does any running surface prevent injury?
Studies analyzing large groups of runners have found that running on soft surfaces does not reduce overall injury rates. (study, study) Like most miracle cures (cough cough minimalist footwear) it doesn’t hold up well when scientists look into it. Sadly, soft surfaces are probably not the solution to any runners’ injury problems.
Here’s why,
Running on soft surfaces changes what the brain tells the legs to do. When we switch from a hard surface to a soft surface, the foot hits the soft ground for the first time and immediately sends a signal to the brain. Then, the brain responds. It tells the leg, “my main priority is keeping this human upright and their center of mass in the same position, so I’m going to need you (the leg) to put out a little more force to balance out this squishy surface.” (There’s even a whole scientific paper on that first step if you want to nerd out.)
“Wait, ‘more power?’ I thought soft surface running was supposed to be easier on my body?”
Well, here’s where it gets tricky. Your body’s top priority is to keep its center of mass at the same height off the ground. When the ground squishes a bit, your leg has to work harder to keep you in the same position and posture. This increase in force is most notable in the achilles tendon.
Soft ground, stiff muscles. Hard ground, softer muscles. So, does this mean softer surfaces might actually increase your injury risk?
Could a running surface increase risk of injury?
The answer is a confident “maybe,” and funnily enough, we know more about ways that difference surfaces can hurt you than help you.
Treadmills, grass, dirt, and especially sand are all very soft. This leads to increased loads through the achilles tendon (like we mention above – your leg needs to put out more power). If you have a history of achilles tendon issues or are a masters runner (those over 40 are at higher risk for calf and achilles injuries (study)) soft surfaces may actually increase your risk of achilles pain or injury (study).
Wild!
So, what surfaces should you run on?
Answer: all of them, unless you’ve got an achilles problem! Run on trails – run on treadmills – run on a track made of marshmallows if it makes you happy. Variety is fun, and the surfaces just don’t matter that much! But, if you’re nursing a sore achilles, try the sidewalk and do some strengthening exercises. If you’ve never had a sore achilles in your life, run wild and don’t worry about it. The effects of different surfaces on running injury rates are SMALL.
Here are two things you can do that will significantly reduce your risk of injury.
Carefully monitor your training load: be careful to not do too much too soon and incorporate periods of less training load (down weeks.)
Strength training has been shown to decrease overuse injury rates in athletes by up to 50%
If you want a custom recovery routine with PT exercises specific to your running related soreness, try the Recover Athletics app. It uses evidence based techniques to help you run more, hurt less, and recover better!
