The really obvious thing, if you watch the Freeze "best of" clip, is that most people have terrible running form. In most cases, I suspect I could tell who has a chance and who doesn't simply by looking at one stride from each competitor.

There are so many factors that go into biomechanics--I struggle to improve my own running form--but it's interesting to me that it comes together in such an obvious-at-a-glance factor as "looks fast."