title: Prevalence of Youth Fitness in the United States: Baseline Results from the NFL PLAY 60 FITNESSGRAM Partnership Project.
abstract: OBJECTIVE
  To assess age- and sex-specific patterns of 6 health-related fitness components in youth, baseline data from the NFL PLAY 60 FITNESSGRAM Partnership Project were analyzed.
  
  
  METHODS
  A total of 192,848 students from 1st through 12th grade in 725 schools completed the standard FITNESSGRAM testing in 2010-2014, including assessments of aerobic capacity (AC), body mass index (BMI), upper body strength and endurance, trunk extensor strength and flexibility, abdominal strength and endurance, and flexibility. Individual data were aggregated by grade and sex. Age- and sex-specific health-related criterion-referenced standards were used to classify fitness results into the healthy fitness zone (HFZ), needs improvement zone, or needs improvement health risk.
  
  
  RESULTS
  The proportion of youth meeting the HFZ for AC varied considerably by grade for both boys (62.1%-37.6%) and girls (49.1%-26.1%) among 1st-12th grade. There was less variability by age and sex for achievement of the BMI HFZ (ranged from 52.7%-65.0%). The prevalence of achievement was similar for the remaining fitness components. Significantly lower achievement was found in the middle school years for BMI HFZ in both sexes and for AC HFZ achievement in boys. Continuous age-related lower HFZ achievement was evident in girls for AC.
  
  
  CONCLUSIONS
  The results provide updated health-related fitness profiles for US youth and identify the critical ages when youth fitness levels start to decline.
authors.affiliation: Department of Kinesiology, College of Human Science, Iowa State University, Ames, IA. Electronic address: ybai@iastate.edu.
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Kinesiology, College of Human Science, Iowa State University, Ames, IA.
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Saint-Maurice
authors.affiliation: Department of Kinesiology, College of Human Science, Iowa State University, Ames, IA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Welk
authors.affiliation: The Cooper Institute, Dallas, TX.
authors.forename: Kelly
authors.initials: K
authors.lastname: Allums-Featherston
authors.affiliation: The Cooper Institute, Dallas, TX.
authors.forename: Norma
authors.initials: N
authors.lastname: Candelaria
authors.affiliation: The Cooper Institute, Dallas, TX.
authors.forename: Katelin
authors.initials: K
authors.lastname: Anderson
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength; D010101:Oxygen Consumption; D010807:Physical Endurance; D010809:Physical Fitness; D012015:Reference Standards; D014481:United States