title: The International Fitness Scale (IFIS): usefulness of self-reported fitness in youth.
abstract: BACKGROUND
  We examined: (i) the usefulness of the International Fitness Scale (IFIS) to correctly rank adolescents into physical fitness levels; (ii) the capacity of the IFIS for predicting cardiovascular disease (CVD) risk; and (iii) the reliability of the IFIS in adolescents.
  
  
  METHODS
  The study comprised 3059 adolescents (aged 12.5-17.5 years) from nine European countries (HELENA study). Blood samples were collected in one-third of the participants (randomly selected, n = 981). Test-retest reliability of the IFIS was studied in a separate sample of 277 adolescents. Physical fitness-cardiorespiratory fitness (CRF), muscular fitness (MF), speed-agility (SP-AG), flexibility and overall fitness-was self-reported using 5-point Likert-scale questions (1 = very poor, 5 = very good) and measured using standard field-based tests. The CVD risk factors measured included total/central adiposity indices and mean arterial pressure, total and high density lipoprotein cholesterol, triglycerides, insulin resistance (HOMA) and C-reactive protein.
  
  
  RESULTS
  Analysis of covariance showed that adolescents reporting better fitness had higher measured fitness levels for all the variables studied (all P < 0.001), regardless of gender, age and weight status. Adolescents reporting very good overall fitness, CRF and SP-AG had a healthier cardiovascular profile in eight out of nine CVD risk factors studied. Perfect agreement (same test-retest answer) was observed in 65% of the adolescents and perfect-acceptable agreement (same answer or ±1) in 97% of the adolescents.
  
  
  CONCLUSIONS
  (i) The IFIS is able to correctly rank adolescents according to their measured physical fitness levels; (ii) adolescents reporting a good/very good overall fitness, CRF or SP-AG have a more favorable cardiovascular profile; and (iii) The IFIS is reliable in adolescents.
authors: Department of Biosciences and Nutrition, Unit for Preventive Nutrition, Karolinska Institutet, Huddinge, Sweden. ortegaf@ugr.es
authors: Francisco B
authors: FB
authors: Ortega
authors: Jonatan R
authors: JR
authors: Ruiz
authors: Vanesa
authors: V
authors: España-Romero
authors: Germán
authors: G
authors: Vicente-Rodriguez
authors: David
authors: D
authors: Martínez-Gómez
authors: Yannis
authors: Y
authors: Manios
authors: Laurent
authors: L
authors: Béghin
authors: Dénes
authors: D
authors: Molnar
authors: Kurt
authors: K
authors: Widhalm
authors: Luis A
authors: LA
authors: Moreno
authors: Michael
authors: M
authors: Sjöström
authors: Manuel J
authors: MJ
authors: Castillo
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000704:Analysis of Variance; D001774:Blood Chemical Analysis; D001795:Blood Pressure Determination; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000453:epidemiology*; D002648:Child; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D007391:International Cooperation; D008297:Male; D016017:Odds Ratio; D010808:Physical Examination / Q000379:methods; D010809:Physical Fitness; D011237:Predictive Value of Tests; D015995:Prevalence; D018570:Risk Assessment; D017678:Sex Distribution; D012959:Socioeconomic Factors; D013548:Sweden