Cardiorespiratory Fitness in Indonesian Adolescents: Limited Role of BMI and Dominant Influence of Age and Sex in a Large Cross-Sectional Study

Authors

• Anies Setiowati, Department of Sports Science, Faculty of Sports Science, Universitas Negeri Semarang, IndonesiaFollow
• Sri Sumartiningsih, Department of Sports Science, Faculty of Sports Science, Universitas Negeri Semarang, IndonesiaFollow
• Nur Ilhaini Sucipto, Departement of Medicine, College of Medicine, Taipei Medical University, Taipei, TaiwanFollow
• Fatih Hazar, Department of Sports Science, Faculty of Sport Sciences, Bitlis Eren University, TurkeyFollow
• Philip X. Fuchs, Department of Physical Education and Sport Sciences, National Taiwan Normal University, Taipei,TaiwanFollow

Abstract

Background: Cardiorespiratory fitness (CRF) is a crucial indicator of long-term cardiovascular and metabolic health. Whether body mass index (BMI) independently predicts CRF beyond demographic factors in large, real-world adolescent cohorts remains inconsistently defined. Objective: To determine the independent contributions of body mass index (BMI), age, and sex to cardiorespiratory fitness among Indonesian adolescents using a large community-based dataset.. Methods: A cross-sectional study was conducted using community-based fitness screening data from Central Java, Indonesia. A total of 2,730 adolescents aged 10-18 years (mean 13.3 +/- 2.2 years; 49.6% male) were included. The primary outcome was CRF measured by the 1,600-meter run time (seconds). BMI was analyzed as both a continuous and a categorical variable. Multivariable linear regression models, including non-linear Restricted Cubic Spline (RCS) modeling, were applied. Result: The median run time was 453.0 seconds (IQR 360.6-660.0). Males ran significantly faster than females (491.4 vs. 658.6 seconds; t = -3.02, p = 0.003). BMI category was not significantly associated with run time (ANOVA F = 0.34, p = 0.799) or in adjusted models (beta = 3.8, p = 0.621). Age (beta = 56.7 s/year, p < 0.001) and sex (beta = 156.5 s, p = 0.005) were the sole significant predictors. Neither linear nor non-linear BMI modeling improved model fit (adjusted R2 ~1.0%). Conclusion: BMI did not independently predict CRF in this large Indonesian adolescent cohort. Age and sex were the dominant predictors. These findings challenge the use of BMI as a CRF surrogate in school-based health screening and call for direct fitness assessments with age- and sex-standardized benchmarks.

Recommended Citation

Setiowati, Anies; Sumartiningsih, Sri; Sucipto, Nur Ilhaini; Hazar, Fatih; and Fuchs, Philip X. (2026) "Cardiorespiratory Fitness in Indonesian Adolescents: Limited Role of BMI and Dominant Influence of Age and Sex in a Large Cross-Sectional Study," Indonesian Journal of Research in Physical Education, Sport, and Health: Vol. 4: No. 1, Article 11.
Available at: https://citeus.um.ac.id/ijrpesh/vol4/iss1/11