Background: Low cardiorespiratory fitness (CRF) and low musculoskeletal fitness (MSF) are important risk factors for future cardio-metabolic disease in adolescents, yet global physical fitness surveillance in adolescents, and all other age groups, is poor.
Goal: To describe the prevalence of low health-related physical fitness, including CRF, MSF, body mass index (BMI), and waist circumference (WC) of a large, population-based sample of 8th graders; and to identify independent physical fitness and sociodemographic correlates of each of the 4 physical fitness components.
Methods: The present cross-sectional study was based on 19,929 8th graders (median age = 14 years) in the 2011 National Education Survey (SIMCE) from all regions of Chile. CRF was assessed with the 20 m shuttle run test, MSF with standing broad jump, and body composition with BMI and WC. CRF, MSF, BMI, and WC were classified according to health-related standards. Regression adjusted for sociodemographic (age, socioeconomic status (SES), school type, urban versus rural, and region) and physical fitness characteristics.
Results: Girls had significantly higher prevalence of high-risk CRF, low MSF, and high-risk BMI than boys. Individual components of low physical fitness were significantly independently associated with each other and with many demographic characteristics. Notably, BMI and WC were significant independent correlates of CRF. BMI but not WC was a significant independent correlate of MSF. Adjusted significant declines in prevalence of low fitness by all 4 measures were observed from the highest of 5 SES groups to the lower 4. Students at private schools had significantly lower prevalence of low fitness by all 4 measures than counterparts at subsidized or public schools.
Conclusions: Prevalence of high-risk CRF, low MSF, and high-risk BMI was relatively high in the Chilean 8th graders compared with estimates of adolescent fitness from other countries, especially in girls. Higher prevalence of low health-related physical fitness in students of lower SES and non-private schools suggests opportunity for targeted intervention.
Table of Contents
Literature Review... 1
Introduction and definition of terms. 1
Contributions of obesity, physical activity, fitness to non-communicable disease risk and mortality in adults 2
Relationship between obesity, physical activity, and fitness in adults 4
Contributions of youth obesity, physical activity, and fitness to non-communicable disease risk 8
Relationship between obesity, physical activity, and fitness in youth 10
Fitness surveillance in adolescents. 12
Demographic influence on obesity, physical activity, and fitness 15
The transition towards non-communicable diseases in Latin America 19
Chile as a case study of the epidemiologic transition. 20
Summary of identified needs. 29
Study Objectives. 30
SIMCE Overview.. 31
The Sample. 31
Variable selection. 34
Variable classification. 36
Statistical Analysis. 50
Descriptive statistics. 54
Bivariate associations. 54
Multivariate models. 56
Contextualization of health-related fitness. 60
Explanations for observed low health-related fitness. 67
Adjusted correlates of health-related fitness. 70
Public health implications. 80
IRB Letter of Exemption 143
About this Master's Thesis
|Committee Chair / Thesis Advisor|
|Health-related fitness in Chilean 8th graders ()||2018-08-28||