Nothing revolutionary but this is the first time I've seen it concluded from a study. http://news.yahoo.com/s/livescience/20100127/sc_livescience/runningshoeschangedhowhumansrun Cliffs: 1. There's more impact when you strike heel-first, but it hasn't been shown to be any harder on your body. 2. Landing toe-first uses more foot/calf muscle. 3. Kenyans run fast.