Secular trends in the physical fitness of Brazilian youth: Evidence that fitness is declining for the majority but not for a fit minority

Abstract

BackgroundThere 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.MethodsThis 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.ResultsANOVAs 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.ConclusionsResults 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.

Temporal trends in weight-based disparities in physical fitness of children: 30-years of continuous surveillance through Slovenian national system

“…43,58 Irrespective of weight status, several recent systematic reviews provided an update on general trends in relative muscle strength and handgrip strength and showed a general increasing trend, 23,59 either small negative quadratic trend or stability in muscle power proxies and for speed a small-to-medium increase in recent years no differences between sexes. 23,27,59 Some more recent individual studies showed declines such as the study among Brazilian youth in almost all tests related to MF 37 and adolescents from the United Kingdom. 30 We found an interesting trend in body core strength (i.e., the number of situps in 60s) which increased on average, certainly presenting a challenge in terms of explaining the background of these findings.…”

“…28 That said, fitness trends of children and adolescents from only several high-income countries were reported recently. [27][28][29][30]36,37 Fitness levels, similar to adiposity, can vary significantly across countries and even regions from the same country based on socioeconomic development, so it's important to consider each location's specificities. 36,37 Children and adolescents with lower SES have regularly presented less favourable trends in fitness.…”

“…[27][28][29][30]36,37 Fitness levels, similar to adiposity, can vary significantly across countries and even regions from the same country based on socioeconomic development, so it's important to consider each location's specificities. 36,37 Children and adolescents with lower SES have regularly presented less favourable trends in fitness. 38,39 It is important to note that we are aware of only one study that examined physical fitness trends of children and adolescents where both weight status and SES were considered.…”

Exercise training and physical activity in children: Hard interval training or low hanging fruits to ensure normal growth and maturation for the sake of lifelong physical activity?

“…Based on this, it can be concluded that slightly more than 4 h of physical activity per day, including some moderate‐to‐vigorous intensity activity too, is good goal for children to ensure that their normal growth and maturation as well as fitness develop well in youth. This is important for counteracting worrying global trends in physical (in)activity and fitness in young people 21,22 . It is not forbidden for adults either to try to accumulate as much as possible daily physical activity, in one way or another, to maintain or even increase physical fitness still in adulthood and aging.…”

“…This is important for counteracting worrying global trends in physical (in)activity and fitness in young people. 21,22 It is not forbidden for adults either to try to accumulate as much as possible daily physical activity, in one way or another, to maintain or even increase physical fitness still in adulthood and aging.…”