# Change and Tracking of Physical Fitness Among Children Aged 5–12 Years: A Systematic Review

## TL;DR

This review examines how physical fitness changes in children aged 5–12 and finds that fitness generally improves, with differences between boys and girls.

## Contribution

The study provides a systematic synthesis of longitudinal PF changes and stability in children aged 5–12 years.

## Key findings

- Most studies showed improvements in aerobic, musculoskeletal, and motor fitness in children.
- Boys outperformed girls in aerobic and motor fitness, while girls had better flexibility.
- Stability coefficients for PF components were low-to-moderate, especially for motor fitness.

## Abstract

Background: Understanding physical fitness (PF) trajectories during childhood is essential because they reflect developmental differences and indicate whether early fitness levels predict later outcomes. Clarifying PF tracking is important for school monitoring, early identification of at-risk children, and planning targeted interventions. Objective: To synthesize evidence on change of PF among children aged 5–12 years and, secondarily, to descriptively analyze stability (tracking) of PF components. Methods: Searches were conducted in PubMed, Scopus, PsycINFO, and Web of Science covering the last decade (to May 2025). Longitudinal studies assessing at least one PF component in children aged 5–12 years were included. Data extraction included study/sample characteristics, PF components, assessment tools, statistical methods, and outcomes. Methodological quality was assessed with the NIH Quality Assessment Tool for Observational Cohort Studies. Results: From 33,995 records, 18 studies met the criteria, with sample sizes from 147 to 1148 children and follow-up from 12 to 48 months. Most studies reported improvements in aerobic, musculoskeletal, and motor fitness, while flexibility showed mixed results. Boys generally outperformed girls in aerobic, motor, and musculoskeletal fitness, whereas girls performed better in flexibility. Stability coefficients, analyzed in a set of four studies, varied across PF components, and results should be interpreted with caution. Conclusions: PF generally improves during childhood, with sex-specific patterns and low-to-moderate stability, particularly for motor fitness.