They are leather so I expect them to stretch over time! If you are unfortunate enough to have a bump I would suggest a different style if you don't want to damage the shoe. The first wear out of the box was a bit uncomfortable but the second try was much better. I hope the third try will be a charm! I probably won't buy them again, but I won't be returning them either! It is best to use them for their intended purpose. cross training. But for running I prefer Nimbus!