It looks like the new Adidas trainers played their part. All of the top 3 in the marathon were wearing them yesterday, and they made them much lighter and springier than the previous iteration. I think I read that for elite athletes, the new shoes were saving about 1% in running economy, which over two hours is about a minute, and that's what Sawe knocked off the old world record.
Obviously there's a lot more to it than that, and Sawe is genuinely a Usain Bolt-like freak for long distance running, but the shoes certainly helped.
