title: Age differences in change-of-direction performance and its subelements in female football players.
abstract: OBJECTIVE
  To describe cross-sectional age differences in change-of-direction performance (CODp) in female football players and investigate the relationship between CODp and linear-sprint speed, muscle power, and body size.
  
  
  METHODS
  A sample of 135 well-trained female football players was divided into 8 age groups. Anthropometry (height, body mass, and lean body mass) and athletic performance (10-m sprint speed, 10-m×5-CODp, and 5-step bounding distance) were compared to determine interage differences using ANOVA. Then, the participants were divided into 3 age groups: 12- to 14-y-olds, 15- to 17-y-olds, and ≥18 y-olds. Simple- and multiple-regression analyses were conducted to determine the correlation between CODp and the other measurement variables in each age group.
  
  
  RESULTS
  Age-related differences were found for CODp (F=10.41, P<.01), sprint speed (F=3.27, P<.01), and bounding distance (F=4.20, P<.01). Post hoc analysis revealed that the CODp of 17-y-old players was faster than that of 16-y-old players (P<.01), with no interage differences in sprint speed and bounding distance. Sprint speed and bounding distance were weakly correlated with CODp in 15- to ≥18-y-old players, but only sprint speed was correlated with CODp in 12- to 14-y-old players.
  
  
  CONCLUSIONS
  CODp improves from 16 to 17 y of age in female players. Linear-sprint speed, muscle power, and body size were weakly correlated with the age differences in CODp.
authors.affiliation: Faculty of Sport Sciences, Waseda University, Tokyo, Japan.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Hirose
authors.forename: Chikako
authors.initials: C
authors.lastname: Nakahori
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000367:Age Factors; D054874:Athletic Performance; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005538:Football / Q000502:physiology*; D006801:Humans; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012420:Running / Q000502:physiology*; D055815:Young Adult