I have run many 5k, 5m, 10k, 15k, 10m, half marathons and even a few marathons so know I running socks . Now I just run for fun, but I still know what works. These socks fit perfectly. The last thing I need is for the socks to move and get stuck in the wrong places as I run, so I was very happy that they fit perfectly and stay comfortably on my feet while I run.