@mr.ultrarunner: ⬇️ Black toenails and blisters from running, why!? One reason could be your socks—they might be too slippery on the insole. Check your socks now and write in the comments whether they slide or not. I strongly recommend testing your running socks this way before a race, and your toes will stay safe. ❗️ Important. The photo of damaged toenails was taken from the internet for illustration purposes and does not relate to any specific brand of shoes or socks. #trailrunninglife #trailrunners #runningtips #runninglife #trailrunner #ultrarunners #ultratrailrunner