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J Sports Med Phys Fitness. 2018 May;58(5):630-637. doi: 10.23736/S0022-4707.17.07480-1. Epub 2017 May 9.

Allometric associations between body size, shape, and 100-m butterfly speed performance.

Author information

Research Unit (UR17JS01), "Sport Performance Health and Society", Higher Institute of Sport and Physical Education of Ksar Said, University of La Manouba, Tunis, Tunisia.
Faculty of Education, Health, and Wellbeing, University of Wolverhampton, Walsall, UK.
Research Unit (UR17JS01), "Sport Performance Health and Society", Higher Institute of Sport and Physical Education of Ksar Said, University of La Manouba, Tunis, Tunisia -
Tunisian Research Laboratory "Sports Performance Optimization", National Center of Medicine and Science in Sports (CNMSS), Tunis, Tunisia.
Higher Institute of Sports and Physical Education, Manouba University, Tunis, Tunisia.



This study aimed to estimate the optimal body size, limb-segment length, and girth or breadth ratios associated with 100-m butterfly speed performance in swimmers.


One-hundred-sixty-seven swimmers as subjects (male: N.=103; female: N.=64). Anthropometric measurements comprised height, body-mass, skinfolds, arm-span, upper-limb-length, upper-arm, forearm, hand-lengths, lower-limb-length, thigh-length, leg-length, foot-length, arm-relaxed-girth, forearm-girth, wrist-girth, thigh-girth, calf-girth, ankle-girth, biacromial and biiliocristal-breadths. To estimate the optimal body size and body composition components associated with 100-m butterfly speed performance, we adopted a multiplicative allometric log-linear regression model, which was refined using backward elimination.


Fat-mass was the singularly most important whole-body characteristic. Height and body-mass did not contribute to the model. The allometric model identified that having greater limb segment length-ratio (arm-ratio = [arm-span]/[forearm]) and limb girth-ratio (girth-ratio = [calf-girth]/[ankle-girth]) were key to butterfly speed performance. A greater arm-span to forearm-length ratio and a greater calf to ankle-girth-ratio suggest that a combination of larger arm-span and shorter forearm-length and the combination of larger calves and smaller ankles-girth may benefit butterfly swim speed performance. In addition having greater biacromial and biliocristal breadths is also a major advantage in butterfly swimming speed performance. Finally, the estimation of these ratios was made possible by adopting a multiplicative allometric model that was able to confirm, theoretically, that swim speeds are nearly independent of total body size.


The 100-m butterfly speed performance was strongly negatively associated with fat mass and positively associated with the segment length ratio (arm-span/forearm-length) and girth ratio (calf-girth)/(ankle-girth), having controlled for the developmental changes in age.

[Indexed for MEDLINE]

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