After stop running in Mizuno a few years ago I decided to give this shoe a try. I'm happy with the updates Mizuno has done. I felt like the shoe gave me enough support but was not a heavy, clunky trainer. Mizuno claims U4ic midsole weights in 30% lighter and I could tell. I felt the shoes were light and fast and was an enjoyment to pound the pavement the few times I have worn these.