Aim: To describe age and gender differences in estimated maximum oxygen uptake (VO2max) and participation in organized physical activity in Swedish obese children and adolescents, and compare the results with an age-matched reference group representative of the general population.
Methods: Two hundred and nineteen obese children (102 boys, 117 girls, aged 8–16 years, Body Mass Index (BMI) 24.3–57.0 kg.m−2) performed a submaximal bicycle ergometry test and an interview concerning participation in organized physical activity.
Results: The obese children had lower relative VO2max (p < 0.001) than the reference group. In contrast to the reference group no age or gender differences were detected in the obese children aged 11–13 years and 14–16 years. With increased age (after 11 years) the obese children participated less in organized physical activity than the reference group (p < 0.001). In obese adolescents, participation in organized physical activity in leisure time explained 7% and BMI 45% of the variance in relative VO2max.
Conclusion: The obese children had lower relative VO2max, and participated less in organized physical activity than the reference group. The variance in relative VO2max was primarily explained by BMI. Obese adolescents, especially boys, were found to be at risk of physical inactivity.