Wednesday, November 09, 2005

Homo Secretariat   posted by Jason Malloy @ 11/09/2005 08:14:00 AM

Two new reports suggest that humans are nearing their limit of record-breaking running achievement, and that the sex difference provides no evidence of ever closing. Abstracts below the fold:

More males run fast: a stable sex difference in competitiveness in U.S. distance runners
Robert O. Deaner
Evolution and Human Behavior
Article in Press, Corrected Proof

Sex differences in competitiveness are well established, but it is unknown if they originate from sociocultural conditions or evolved predispositions. Testing these hypotheses requires a quantifiable sex difference in competitiveness and the application of a powerful sociocultural manipulation to eliminate it. Study 1 reviews previous work showing that more male distance runners are motivated by competition and maintain large training volumes, suggesting that more males should run fast relative to sex-specific world-class standards. I then use two independent statistical approaches to demonstrate that, in matched populations of male and female U.S. runners, two to four times as many males as females ran relatively fast in 2003. Study 2 investigates whether the growth in opportunities and incentives for female athletes in the past 30 years is eliminating this sex difference. I first show that there was a marked increase in the number of fast female runners in the 1970s and early 1980s, a period during which female participation increased dramatically. However, I found no indication of an absolute or relative increase in the number of fast female distance runners since the mid-1980s. These findings therefore support the hypothesis that sex differences in competitiveness partly reflect evolved predispositions.


Are There Limits to Running World Records?
Medicine & Science in Sports & Exercise. 37(10):1785-1788, October 2005.
Nevill, AM, Whyte, G

Purpose: Previous researchers have adopted linear models to predict athletic running world records, based on records recorded throughout the 20th century. These linear models imply that there is no limit to human performance and that, based on projected estimates, women will eventually run faster than men. The purpose of this article is to assess whether a more biologically sound, flattened "S-shaped" curve could provide a better and more interpretable fit to the data, suggesting that running world records could reach their asymptotic limits some time in the future.

Methods: Middle- and long-distance running world record speeds recorded during the 20th century were modeled using a flattened S-shaped logistic curve.

Results: The logistic curves produce significantly better fits to these world records than linear models (assessed by separating/partitioning the explained variance from the logistic and linear models using ANOVA). The models identify a slow rise in world-record speeds during the early year of the century, followed by a period of "acceleration" in the middle of the century (due to the professionalization of sport and advances in technology and science), and a subsequent reduction in the prevalence of record-breaking performances towards the end of the century. The model predicts that men's world records are nearing their asymptotic limits (within 1-3%). Indeed, the current women's 1500-m world record speed of 6.51 m[middle dot]s-1 may well have reached its limit (time 3:50.46).

Conclusions: Many of the established men's and women's endurance running world records are nearing their limits and, consequently, women's world records are unlikely to ever reach those achieved by men.


Related: African Endurance Running and Genetics, The Physiology of Kenyan Runners, Baby, we were born to run, Born to run!, Born to Run. (Three times the same title; pretty lame, I know. On the other hand 1) I did it first 2) I came up with Homo Secretariat - I mean c'mon!)

Also see Steve's The Gender Gap: Elite Women Are Running Further Behind