Self selection of athletes into sports via skeletal ratios

This study examined differences in physique and skeletal dimensions between 1146elite Caucasian athletes classified into endurance, strength, speed, upper body orcombined sports categories and controls, to test the hypothesis that athletes of certaintypes of sport would exhibit a distinct morphology commensurate with their task.Participants were measured by experienced anthropometrists using an internationallyrecognisedprotocol to describe physique. This involved calculating the anthropometricsomatotype in terms of fatness, musculoskeletal robustness and linearity. Further skeletalmeasures were acquired sufficient to describe an array of morphological indices: cruralindex (tibial height / femur length), skelic index (leg length / sitting height), androgynyindex (biacromial breadth / bicristal breadth) and brachial index (forearm length / upperarm length). Significant inter-group differences in indices prevailed after adjustment for age. Endurance athletes had a high crural index and low brachial index, relative tocontrols. A low skelic index appears characteristic of female strength athletes while a lowbrachial index is typical of female endurance and strength athletes. Bayesian clusteranalysis has shown the crural index in particular is a discriminant in phenotypiccategorisation, in addition to the primary somatotype components of endomorphy,mesomorphy and ectomorphy. These findings are congruent with biomechanicalimperatives to maximise force and/or minimise energy expenditure offering sportsspecificadvantage. Because the skeletal relationships do not respond to the conditioningstimulus in the same way adipose and muscle tissue do, the observed inter-groupdifferences suggest a self-selection of athletes into sports in which they are likely to excel.