Normative Values for Cardiorespiratory Fitness Testing Among US Children Aged 6-11 years.

Background: Nationally representative normative values for cardiorespiratory fitness (CRF) have not been described for US children since the mid 1980s.

Objective: To provide sex- and age-specific normative values for CRF of US children aged 6-11 years.

Methods: Data from 624 children aged 6-11 years who participated in the CRF testing as part of the 2012 National Health and Nutrition Examination Survey National Youth Fitness Survey, a cross-sectional survey, were analyzed. Participants were assigned to one of three age-specific protocols and asked to exercise to volitional fatigue. The difficulty of the protocols increased with successive age groups. CRF was assessed as maximal endurance time (min:sec). Data analysis was conducted in 2016.

Results: For 6-7, 8-9, 10-11 year olds, corresponding with the age-specific protocols, mean endurance time was 12:10 min:sec (95% CI: 11:49-12:31), 11:16 min:sec (95% CI: 11:00-11:31), and 10:01 min:sec (95% CI: 9:37-10:25), respectively. Youth in the lowest 20th percentile for endurance time were more likely to be obese, to report less favorable health, and to report greater than two hours of screen time per day.

Conclusions: These data may serve as baseline estimates to monitor trends over time in CRF among US children aged 6-11 years.