Which do you prefer running on, blacktop, concrete or trail, and why? Do you think that softer running surfaces are less likely to cause injury than harder running surfaces? I always felt this way too. I’ve purposely planned routes that I knew would have more blacktop instead of concrete, or would sometimes even run beside the concrete sidewalk on the softer grass because I felt that running on softer surfaces would cause less damage to my joints over time. However, the correlation between running on harder surfaces and injuries has yet to be definitively proven one way or another, but softer running surfaces are not always safer. Below I have linked a paper that seems to indicate that the running surface may not be directly correlated to number of injuries and another paper that provides a possible explanation as to why this may be true.
According to “Runners adjust leg stiffness for their first step on a new running surface”, published in the Journal of Biomechanics, the researchers found that muscles actually stiffen more when running on softer surfaces than when running on a harder surface. When you’re running with stiff muscles, you don’t absorb the shock of hitting the ground as well as you would with more relaxed muscles. Even though you’re running on a softer surface the impact forces may not be proportionally less.
“A prospective study of running injuries: the Vancouver Sun Run ‘In Training’ clinics”, published in British Journal of Sports Medicine found that there wasn’t a distinct correlation between running surface and injury rate.
These studies aren’t entirely conclusive, but these two papers, among other papers not listed, do show that the running surface may not be as strongly linked to running injuries as believed.
I would like to encourage you to run on whatever surface you want to. Although it is often believed that running on a softer surface is safer, this may not be true.
As always, it is important to be skeptical when you hear claims and to always do your own research. Just because someone tells you that you should be doing one thing or another doesn’t mean it is necessarily best for you. Even widely accepted claims may not be entirely true.