title: Validation of a noninvasive maturity estimate relative to skeletal age in youth football players.
abstract: OBJECTIVE
  To validate a non-invasive measure of biological maturity (percentage of predicted mature height at a given age) with an established indicator of maturity [skeletal age (SA)] in youth American football players.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  Two communities in central Michigan.
  
  
  METHODS
  143 youth football players 9.27 to 14.24 years.
  
  
  METHODS
  Height and weight were measured, and hand-wrist radiographs were taken. SA assessed with the Fels method was the criterion measure of maturity status. Chronological age (CA), height, and weight of the player and midparent height were used to predict mature height; current height of the player was expressed as a percentage of his predicted mature height as a noninvasive estimate of biological maturity status.
  
  
  METHODS
  Boys' maturation was classified as late, on time, or early maturing on the basis of the difference between SA and CA and of present height expressed as a percentage of predicted mature height. Kappa coefficients and Spearman rank-order correlations were calculated. Characteristics of players concordant and discordant for maturity classification with SA and percentage of predicted mature height were compared with MANCOVA.
  
  
  RESULTS
  Concordance between methods of maturity classification was 62%. The Kappa coefficient, 0.46 (95% CI 0.19 to 0.59) and Spearman rank-order correlation, rs = 0.52 (P < 0.001) were moderate. Players discordant for maturity status varied in midparent height and percentage of predicted mature height, but not in predicted mature height.
  
  
  CONCLUSIONS
  Percentage of predicted mature height is a reasonably valid estimate of biological maturity status in this sample of youth football players.
authors.affiliation: Tarleton State University, Stephenville, Texas, USA. rmalina@skyconnect.net
authors.forename: Robert M
authors.initials: RM
authors.lastname: Malina
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Dompier
authors.forename: John W
authors.initials: JW
authors.lastname: Powell
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Barron
authors.forename: Marguerite T
authors.initials: MT
authors.lastname: Moore
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000886:Anthropometry; D001827:Body Height / Q000502:physiology*; D015992:Body Mass Index; D049628:Body Size; D001835:Body Weight / Q000502:physiology; D001846:Bone Development; D002648:Child; D003430:Cross-Sectional Studies; D005538:Football; D006801:Humans; D008297:Male; D009141:Musculoskeletal System / Q000033:anatomy & histology*; D012863:Skeleton