What's on their fast feet?

Oh yes, I'm into shoes, you know, of course heels, but being pregnant I've been wearing 2 inch sandals which to me is like flats. When watching the Olympics Opening Ceremony tonight and the Olympic games and track races, especially the track races (400 dash!) I'm paying attention to the shoes! I used to wear very colorful shoes when I ran (yes, gotta plug my new book, and in "Careful," and Estella used to run the 400 dash in hot pink racing flats. :)