I loved these trainers from the first sight because of the design and the special X at the back but I had to exchange my usual size 11 to 11.5 because the structure of the shoes is not right, it's tighter from the front and wider from the back, so I had to go up one size to solve the front problem even though the back became wider than it was already. I would normally return the shoes with a silly problem like that, as I walk now and my heels are loose but I couldn't resist the design and I do love it. The only advice I can say is go up next size.