title: Maturity-associated variation in change of direction and dribbling speed in early pubertal years and 5-year developmental changes in young soccer players.
abstract: OBJECTIVE
  The purpose of the current study was to assess the developmental changes in change of direction and dribbling speed in youth soccer players taking into account skeletal age (SA), maturity status, body size, estimated fat mass, aerobic endurance, lower limb explosive strength and annual volume of training.
  
  
  METHODS
  Eighty-three male soccer players aged 10-15 years (SA) at baseline were annually followed over 5 years, resulting in an average 4.4 observations per player. After testing for multicollinearity, multi-level regression modeling was used to examine the longitudinal developmental changes on change of direction and dribbling speed.
  
  
  RESULTS
  Maturity-associated variability was significant in change of direction and also dribbling speed among young soccer players aged 12-14 years with better scores being performed by late maturers. Moreover, the predicted longitudinal scores for change of direction and dribbling speed improved with SA (P<0.01), SA2 (P<0.01) and skeletal maturity status entered as an additional developmental predictor (P<0.05). Estimated fat-free mass (P<0.01), aerobic endurance (P<0.01) and lower limb strength (P<0.01) were additional predictors in both models. The soccer-specific skill, dibbling speed, was also explained by annual volume of training (P<0.05).
  
  
  CONCLUSIONS
  Skeletal maturity status explains inter-individual variability on maximal short-term run performances with and without the ball possession at early ages of participation in competitive soccer. The effects tend to persist across ages combined with longitudinal changes in body composition and functional fitness. In the particular case of the ball test, annual volume of training was also a longitudinal performance predictor.
authors.affiliation: Faculty of Sport Sciences and Physical Education University of Coimbra, Coimbra, Portugal - mjcesilva@fcdef.uc.pt.
authors.forename: J
authors.initials: J
authors.lastname: Valente-Dos-Santos
authors.forename: M J
authors.initials: MJ
authors.lastname: Coelho-E-Silva
authors.forename: V
authors.initials: V
authors.lastname: Vaz
authors.forename: A J
authors.initials: AJ
authors.lastname: Figueiredo
authors.forename: L
authors.initials: L
authors.lastname: Capranica
authors.forename: L B
authors.initials: LB
authors.lastname: Sherar
authors.forename: M T
authors.initials: MT
authors.lastname: Elferink-Gemser
authors.forename: R M
authors.initials: RM
authors.lastname: Malina
mesh_terms: D000293:Adolescent; D000365:Age Determination by Skeleton; D000886:Anthropometry; D054874:Athletic Performance / Q000502:physiology*; D002648:Child; D002657:Child Development / Q000502:physiology*; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D010807:Physical Endurance / Q000502:physiology; D012420:Running / Q000502:physiology*; D012916:Soccer / Q000502:physiology*