Physical Fitness and Body Composition in Youth

Physical fitness in young people encompasses multiple interrelated components—cardiorespiratory endurance, muscular strength and endurance, flexibility and body composition—that together shape both immediate performance and long-term health trajectories. Adequate levels of fitness during childhood and adolescence not only support motor skill development and psychological well-being but also reduce future risk of non-communicable diseases. Recent decades have witnessed worrisome trends: declining aerobic capacity, rising prevalence of overweight and obesity, and notable disparities according to gender, socioeconomic background and geographic setting. Understanding how physical activity patterns, nutritional status and environmental factors interact to influence fitness and body composition is essential for designing effective school- and community-based interventions that promote sustainable healthy lifestyles.

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Physical Fitness and Body Composition in Youth publication trend

The graph below shows the total number of articles in physical fitness and body composition in youth across all publications each year (not limited to Nature Index journals).

Technical terms

Body mass index (BMI): A ratio of weight (kg) to height squared (m²) used to classify underweight, normal weight, overweight and obesity.

Body composition: The relative proportions of fat mass and fat-free mass (including muscle, bone and water) in the body.

Cardiorespiratory fitness: The ability of the circulatory and respiratory systems to supply oxygen during sustained physical activity, often measured by endurance tests.

Muscular strength: The maximal force that a muscle or muscle group can exert in a single effort, assessed via tests such as handgrip or push-ups.

Physical activity levels (PAL): Quantitative measure of all bodily movement produced by skeletal muscles that results in energy expenditure, often tracked by questionnaires or accelerometry.

References

1. Health-related physical fitness, physical activity and its correlates among school going adolescents in hilly state in north India: a cross sectional survey. BMC Public Health (2024).
2. Trend in health-related physical fitness for Chinese male first-year college students: 2013–2019. Frontiers in Public Health (2023).
3. Rural–Urban Differences in Physical Fitness and Overweight Prevalence of Children and Adolescents from Central South China. International Journal of Environmental Research and Public Health (2023).