title: Determinant Factors of Long-Term Performance Development in Young Swimmers.
abstract: OBJECTIVE
  To develop a performance predictor model based on swimmers' biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction.
  
  
  METHODS
  91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors.
  
  
  RESULTS
  Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] -2.05, P < .001), arm span (EST -0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST -0.17, P = .001) were entered in the final model.
  
  
  CONCLUSIONS
  Over 3 consecutive seasons young swimmers' performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Morais
authors.forename: António J
authors.initials: AJ
authors.lastname: Silva
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Marinho
authors.forename: Vítor P
authors.initials: VP
authors.lastname: Lopes
authors.forename: Tiago M
authors.initials: TM
authors.lastname: Barbosa
mesh_terms: D000367:Age Factors; D000886:Anthropometry; D001076:Aptitude; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D002648:Child; D004526:Efficiency / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D064797:Physical Conditioning, Human / Q000379:methods*; D012737:Sex Factors; D013550:Swimming / Q000502:physiology*; D013997:Time Factors
keywords: anthropometrics; biomechanical predictors; contribution; kinematics; talent development; talent identification