Validity of Cardiorespiratory Fitness Criterion-Referenced Standards for Adolescents

Abstract

The clinical utility of cardiorespiratory fitness (CRF) criterion-referenced standards (FITNESSGRAM) has not been tested in adolescents. We aimed to determine the ability of the FITNESSGRAM standards to discriminate between low and high cardiovascular disease (CVD) risk in a population-based sample of US adolescents. Participants included 1247 adolescents (45.7% females) aged 12-19 yr. A submaximal walking treadmill test was used to estimate peak oxygen consumption as a measure of CRF. Participants were dichotomized based on meeting or failing the sex- and age-specific FITNESSGRAM standards. CVD risk factors included systolic blood pressure, sum of triceps and subscapular skinfolds, homeostatic model assessment (HOMA) of insulin resistance, triglycerides, and total cholesterol/high-density lipoprotein ratio. A sex- and age-specific CVD risk score was computed as the mean of these five standardized risk factors. A risk score >1 SD was considered to indicate a high CVD risk. One third of the adolescents fail to meet the FITNESSGRAM standards. Body fat and CVD risk score were significantly lower in adolescents meeting versus failing the FITNESSGRAM standards (all P < 0.003). Receiver operating characteristics curve analyses revealed that the CRF thresholds that best discriminated between low and high CVD risk were very similar to those established by FITNESSGRAM: 44.1 and 40.3 mL x kg(-1) x min(-1) among 12- to 15- and 16- to 19-yr-old boys and 36.0 and 35.5 mL x kg(-1) x min(-1) among 12- to 15- and 16- to 19-yr-old girls, respectively. The CRF criterion-referenced standards established by FITNESSGRAM discriminate adolescents with a more favorable cardiovascular profile from those with a less favorable profile. Identification of children who fail to meet these standards can help detect the target population for pediatric CVD prevention strategies.