Shoes are way too,too narrow in the heal, to the point of hurting foot. Oddly enough they are too wide in toe, while jogging your foot slides around. Another thing I have noticed is my feet sweat more in Salamon trail shoes. I think this is the material used for integrated tongue. Perhaps in an effort to provide some water resistance against morning dew or small puddles, material is not letting water in. Unfortunately, it doesn't breathe either and my feet get really hot.  I have returned these, opting for a pair of ASICS instead.