학술논문

Secular trends in the physical fitness of Brazilian youth: Evidence that fitness is declining for the majority but not for a fit minority.
Document Type
Article
Source
Scandinavian Journal of Medicine & Science in Sports. Oct2023, Vol. 33 Issue 10, p2079-2089. 11p. 4 Charts, 5 Graphs.
Subject
*ANALYSIS of variance
*CONFIDENCE intervals
*CROSS-sectional method
*PHYSICAL fitness
*T-test (Statistics)
*ANALYSIS of covariance
*DESCRIPTIVE statistics
*DATA analysis software
*LONGITUDINAL method
*ADOLESCENCE
Language
ISSN
0905-7188
Abstract
Background: There has been a decline in children's physical fitness in recent decades. Such concerns are largely based on evidence from North America, Europe, and Asia. The current study describes the secular trend and variation (spread) in the physical fitness scores of young Brazilians from 2005 to 2022. Methods: This study is a repeated, cross‐sectional surveillance study (1999–2022). Children and adolescents (n = 65 139; boys = 36 539) participated between 2005 and 2022. In each cohort six physical fitness tests were conducted: (1) 20‐m sprint speed (m s−1), (2) cardio‐respiratory 6‐min run test (m min−1), (3) abdominal strength test (sit‐ups per min), (4) horizontal jump test (cm), (5) the agility test (m s−1), and (6) the medicine ball throw test (cm). Means and distributional characteristics of the population were assessed using ANOVA, ANCOVA adopting BMI as the body‐size covariate, Levene's test of equality‐of‐error variances, and Box and whisker plots. Results: ANOVAs and ANCOVA's identified significant declines in physical fitness over time/year in 5 of the 6 physical fitness variables (e.g., 20‐m sprint speed slope B = −0.018 (m s−1 y−1); 95% CI −0.019 to −0.017; p < 0.001), the only exception being the medicine ball throw test (cm). The Levene's test of equality‐of‐error variances also identified a systematic increase in the variances/standard deviations over time/years. Conclusions: Results provide powerful evidence that children and adolescents' physical fitness is declining, a trend that is also diverging asymmetrically, becoming more extreme in more recent years. The "fit" appear to be getting fitter, but the fitness of the "less‐fit" appears to be declining further. These results have important implications for sports medicine and government policy makers. [ABSTRACT FROM AUTHOR]