Wednesday, September 03, 2008

Academics on Bolt

  1. Usain Bolt: It's just not normal by Justin Wolfers.

    Usain Bolt’s wonderful run in the Olympic 200-meter sprint reminds us that the normal distribution — the familiar bell curve beloved by economists and statisticians — can be wildly inappropriate when analyzing extremely selected samples.

    This morning’s New York Times shows Usain Bolt’s new world record, relative to the 250 greatest 200-meter sprints ever. Not only does this not look like a normal distribution, it doesn’t even look like the tail of any standard distribution I’ve ever seen.

    BTW, this infographic on the history of world records is a fascinating time sink!

  2. The gene for Jamaican sprinting success? No, not really by Daniel MacArthur.

    I'm certainly not arguing here that genetics doesn't play any role in Bolt's success - or in the remarkable over-representation of West African descendents in Olympic short-distance track events, or the similarly impressive skew towards East Africans among marathon runners. ... Rather, my point is that an excessive emphasis on ACTN3 as a major explanation for Jamaican success does a grave disservice to the complex interplay of genetic and environmental factors required for top-level athletic performance. This suggestion goes against everything we've learnt about the genetics of complex traits from recent genome-wide association studies, which have revealed that quantitative traits (like height and body weight) are frequently influenced by dozens to hundreds of genes, each of small effect; if anything, it's likely that athletic performance will be even more genetically complex than these traits. The ACTN3-centred argument also dismisses the importance of Jamaica's impressive investment in the infrastructure and training system required to identify and nurture elite track athletes, the effects of a culture that idolises local track heroes, and the powerful desire of young Jamaicans to use athletic success to lift themselves and their families out of poverty.

    It is almost certainly true that Usain Bolt carries at least one of the "sprint" variants of the ACTN3 gene, but then so do I (along with around five billion other humans worldwide). Indeed, I'm fortunate enough to be lugging around two "sprint" copies - but that doesn't mean you'll see me in the 100 metre final in London in 2012. Unfortunately for me, it takes a lot more than one lucky gene to create an Olympian.

  3. Velocity dispersions in a cluster of stars: How fast could Usain Bolt have run? by H. K. Eriksen, J. R. Kristiansen, O. Langangen, I. K. Wehus. Link via Sean Carroll.

    Since that very memorable day at the Beijing 2008 Olympics, a big question on every sports commentator’s mind has been “What would the 100 meter dash world record have been, had Usain Bolt not celebrated at the end of his race?” Glen Mills, Bolt’s coach suggested at a recent press conference that the time could have been 9.52 seconds or better. We revisit this question by measuring Bolt’s position as a function of time using footage of the run, and then extrapolate into the last two seconds based on two different assumptions. First, we conservatively assume that Bolt could have maintained Richard Thompson’s, the runner-up, acceleration during the end of the race. Second, based on the race development prior to the celebration, we assume that he could also have kept an acceleration of 0.5 m/s^2 higher than Thompson. In these two cases, we find that the new world record would have been 9.61 +/- 0.04 and 9.55 +/- 0.04 seconds, respectively, where the uncertainties denote 95% statistical errors.