RESUMO
The purpose of the current article was to use allometric models to identify the best body size descriptors and other anthropometric variables, body composition, and offset maturity that might be associated with the youngsters' 50m personal-best (PB) swim speeds (m·s-1). Eighty-five competitive swimmers (male, n=50; 13.5±1.8 y; female, n=35; 12.6±1.8 y) participated in this study. Height, body mass, sitting height, arm span, skinfolds, arm muscle area (AMA), and maturity offset were assessed. Swimming performance was taken as the PB time recorded in competition, and the propulsive force of their arm (PFA) was assessed by the tied swimming test. The multiplicative allometric model relating 50m PB swim speeds (m·s-1) to all the predictor variables found percentage body fat as a negative [(BF%) ß= -.121±.036; P=0.001], and PFA (PFA ß=.108±.033; P=0.001) and the girl's arm span (ß=.850±.301; P=0.006), all log-transformed, as positive significant predictors of log-transformed swim speed. The adjusted coefficient of determination, Radj2 was 54.8% with the log-transformed error ratio being 0.094 or 9.8%, having taken antilogs. The study revealed, using an allometric approach, that body fatness and PFA were significant contributors to 50m freestyle swim performance in young swimmers.
Assuntos
Desenvolvimento do Adolescente/fisiologia , Desempenho Atlético/fisiologia , Composição Corporal/fisiologia , Tamanho Corporal/fisiologia , Desenvolvimento Infantil/fisiologia , Natação/fisiologia , Adolescente , Antropometria , Criança , Feminino , Humanos , MasculinoRESUMO
Youth swimming performance may be influenced by anthropometric and body composition factors during growth. Propulsive force of the arm (PFA) is highly related to swimming performance as 85-90% of the propulsive power comes from the arms. The current study analyzed the mediating effect of biological maturation on the relationship between anthropometric variables and body composition with PFA in young swimmers. A total of 128 swimmers [boys: n = 53, age = 13.6 (1.8) y; girls: n = 75, age = 12.5 (1.8) y] were evaluated. Propulsive force of the arm was estimated by the tethered swimming test. Anthropometric characteristics (body mass, stature, sitting height, arm span, arm muscle area, %body fat, and fat-free mass) were evaluated. Biological maturation was estimated by the age of peak height velocity. Mediation analyses were performed using the Preacher and Hayes bootstrapping method, adjusted for chronological age and sex. All anthropometric and body composition variables, except %body fat, were positively associated with PFA, being mediated by biological maturation. Indirect effects and 95% confidence intervals were: body mass [.20 (.09-.34)], stature [.22 (.11-.43)], arm span [0.17 (.05-.31)], arm muscle area [.74 (.38-1.19)] and fat free-mass [.17 (.05-.34)]. In conclusion, biological maturation mediated the positive associations between body size and composition and PFA in young swimmers.