This study aimed to determine the influence of age, anthropometry, and distance on stroke parameters of 10- to 17-y-old swimmers. Forty-six male swimmers were divided into 4 chronological age groups. Anthropometry and sexual maturity were assessed, and maximal efforts of 100, 200, and 400 m using front-crawl style were performed to determine stroke rate (SR), length (SL), and index (SI). Multiple linear regression, 1-way, and mixed ANOVA for repeated measures were used for statistical analyses. There was significant effect of distance for all stroke parameters (P < .001) and an age effect only for SL and SI (P < .001). Post hoc showed that the 10- to 17-year-old group significantly reduced SR with increasing distance (effect size –0.8 to –1.5 comparing 100, 200, and 400 m) but were not effective in offsetting this adaptation with increased SL, especially from 200- to 400-m distance, at which no group made both adjustments, highlighting the decreased efficiency with significant SI reduction (effect size –0.2 to –0.4 comparing 100, 200, and 400 m). Considering all stroke parameters, the performances were almost 100% explained, but SI itself could explain around 90% of the performance; furthermore, limb length contributed to explain all stroke parameter, and SI was the variable best predicted (around 75%) by anthropometrical (upper limbs and height) and descriptive variables (age and y of systematic training).Thus, distinct effects of distance and advancing age were found during childhood and adolescence on stroke parameters, and SI was highlighted as the best predictor of 100-, 200-, and 400-m maximal performances.
Mezzaroba is with the Postgraduate Program in Physical Education UEM/UEL, and Machado, the Dept of Physical Education, State University of Maringá, Maringá, Brazil. Address author correspondence to Fabiana Machado at email@example.com.