Identifying the ideal "body shape" associated with athletic performance using three dimensional (height, body mass and waist) allometry.

The purpose of the current study was to identify the most appropriate "body shape" associated with six athletic performance (AP) tests, using three-dimensional allometry (height (HT), body mass (M), and waist circumference (WC)), in a sample of Brazilian children and adolescents. The sample consisted of 11018 Brazilian children/adolescents (5147 boys) aged 7-17 years. The 6 AP tests were, a 20 m sprint test, an agility test, a 6/9 minute walk/run endurance test, an upper body strength test, an abdominal muscular endurance test, and a lower limb strength test. The "three-dimensional" allometric model was, A P = a ⋅ M k 1 ⋅ H T k 2 ⋅ W C k 3 . Results indicated that two of the three body-size dimensions (HT and WC) were consistently associated with all six athletic performance tests. These were a positive HT exponent/term together with a negative WC exponent/term, confirming that being taller benefited all six performance tests but excess WC was always detrimental. The contribution of M depended on whether the athletic performance required the children/adolescent to perform the exercise/test in a "weight-baring" protocol, i.e. having to perform the test carrying their own body weight or not. In conclusion, three-dimensional allometry provides new insights into what constitutes the "ideal" athletic shape associated with children/adolescents.