I'm a sucker for these type of analysis and article. It is a lot of fun to read when it isn't really connected to "significant" physics research, mainly because for me, it is a pleasant diversion from my work, but still intellectually stimulating. Furthermore, exercise like this can be something fun for a class or a group of students to do, because it is something they have seen or heard about, and it is based on really basic physics that they can do or follow along.
This is a preprint of a paper that will appear in AJP. It analyzes the mechanics of Usain Bolt's 100m sprints, both from the last Beijing Olympics in 2008, and the recent Track and Field Championship in 2009, both resulting in new world records.
Abstract: At the 2008 Summer Olympics in Beijing, Jamaican athlete Usain Bolt broke the world record for the 100 m sprint. Just one year later, at the 2009 World Championships in Athletics in Berlin he broke it again. A few months after Beijing, Eriksen et al. studied Usain Bolt's performance and predicted that the record could be about one-tenth of second faster, which was confirmed in Berlin. In this paper we extend the analysis of Ref.  to model Bolt's velocity profile for the Beijing 2008 and Berlin 2009 records. From the results we obtained, we were able to deduce the maximum force, the maximum power and the total mechanical energy produced by the athlete in both races. Surprisingly, we concluded that all of these values were smaller in 2009 than in 2008.
Oooh.. now that last part is, indeed, surprising. You have to read it to find out why! :)
Edit: this has now appeared in AJP. The exact citation is:
O. Helene and M.T. Yamashita, Am. J. Phys. v.78, p.307 (2010).