title: Running economy in early and late maturing youth soccer players does not differ.
abstract: OBJECTIVE
  The aim of this study was to investigate the influence of maturity on running economy in a population of young soccer players.
  
  
  METHODS
  13 boys (mean age 14.3 years) active in soccer were divided into two groups: 6 early and 7 late maturers. Anthropometrical characteristics, respiratory exchange ratio, heart rate and maximal oxygen uptake were measured. Running economy was assessed at three submaximal running speeds (8, 9.5 and 11 km/h). Allometric coefficients were calculated and used to diminish the effect of body mass. In addition, running style was analysed biomechanically (stride length and meaningful kinematic values).
  
  
  RESULTS
  There was no significant difference in the running economy of early and late maturing soccer players, nor any significant differences in mass adjusted physiological values. Therefore physiological differences cannot explain why late maturers succeed in keeping up with early maturers. Late maturing boys take longer relative strides, and have more anteversion of the thigh at heel contact, a smaller knee-angle during swing-phase and a lower mass moment of inertia.
  
  
  CONCLUSIONS
  Running style seems to be an important determinant in running economy of children.
authors.affiliation: Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Segers
authors.forename: D
authors.initials: D
authors.lastname: De Clercq
authors.forename: M
authors.initials: M
authors.lastname: Janssens
authors.forename: J
authors.initials: J
authors.lastname: Bourgois
authors.forename: R
authors.initials: R
authors.lastname: Philippaerts
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology*; D000704:Analysis of Variance; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D011627:Puberty / Q000502:physiology; D012420:Running / Q000502:physiology*; D012916:Soccer / Q000502:physiology*