A Body Composition and Anthropometric Indicators as Predictors of Health-Related Fitness

Abstract

Background: Cardiorespiratory fitness is a key health indicator in young adults and can be influenced by anthropometric characteristics and body composition. Body Mass Index (BMI), body fat percentage, and Waist-to-Hip Ratio (WHR) are indicators that can be used to describe these characteristics. However, findings regarding the contribution of each indicator to cardiorespiratory fitness remain inconsistent. This study aims to analyze the relationship of BMI, body fat percentage, and WHR with the cardiorespiratory fitness index among university students.

Research Methods: This study employed a cross-sectional design involving second-year students from the Department of Nutrition at Poltekkes Kemenkes Surabaya. A total of 98 respondents participated in the study. Data collected included body weight, height, body fat percentage, waist circumference, and hip circumference. Cardiorespiratory fitness was measured using the Harvard Step Test. Bivariate analysis was conducted using Spearman correlation, while multivariate analysis utilized multiple linear regression with heteroskedasticity-consistent standard errors (HC3).

Research Result: The mean age of the respondents was 18.68 ± 0.62 years; BMI was 22.65 ± 4.86 kg/m²; body fat percentage was 27.67 ± 6.70%; WHR was 0.80 ± 0.06; and the Harvard Step Test score was 71.31 ± 16.51. Bivariate analysis revealed a very strong negative correlation between BMI and the Harvard Step Test (r = −0.816; p < 0.001) and a moderate negative correlation between body fat percentage and the Harvard Step Test (r = −0.508; p < 0.001). WHR did not show a significant relationship with the Harvard Step Test (r = −0.191; p = 0.059). Regression analysis indicated that BMI was the only significant predictor when controlled for body fat percentage and WHR (B = −2.863; 95% CI: −3.945 to −1.780; p < 0.001). Body fat percentage (B = 0.285; p = 0.377) and WHR (B = −26.037; p = 0.246) did not show significant associations. The model simultaneously explained 57.9% of the variation in the Harvard Step Test, with an Adjusted R² of 56.6%.

Conclusion: BMI is the anthropometric indicator most consistently associated with the cardiorespiratory fitness index among university students. The higher the BMI, the lower the Harvard Step Test score. Although body fat percentage showed an association in the bivariate analysis, this relationship was no longer significant after controlling for BMI and the waist-to-hip ratio.