Temporal trends in standing long jump performance of 6,233,940 Chinese children and adolescents between 2000 and 2025

Background/objective Muscular strength is a powerful marker of current and future health status. Standing long jump (SLJ) is a convenient, feasible, and common method of assessing muscle power, which has historically been measured among Chinese children and adolescents. The aim of this study was to examine temporal trends in SLJ performance among Chinese children and adolescents from 2000 to 2025.Methods Systematic searches were conducted in six databases/web search engines (China National Knowledge Infrastructure, PubMed, Web of Science, MEDLINE, CINAHL, and SPORTDiscus) up to August 1, 2026. Trends in means of SLJ were assessed using General Linear Models (proc GLM), with different adjustment and stratification strategies for sex and school grade. The systematic review included 88 eligible studies and reports, providing SLJ data for 6,233,940 participants for temporal trend analyses, and raw data from an additional 22,346 participants were collected to harmonise the number of test attempts.Results SLJ performance declined among Chinese children and adolescents (effect size, ES) per decade [95% CI]: - 0.52 [ - 0.56, - 0.48] or - 6.88 cm [ - 7.50, - 6.27] over the entire period, with a negligible improvement pre-2010 and a small decline post-2010. We observed a small sex-related temporal difference, with a more pronounced decline for boys (ES per decade [95% CI]: - 0.70 [ - 0.77, - 0.63]) than girls (ES per decade [95% CI]: - 0.34 [ - 0.39, - 0.30]). There were small declines for primary and middle school students, while there was a moderate decline for high school students. A substantial increase in distributional variability was also found (ratio of CVs [95% CI]: 1.28 [1.25, 1.30]).Conclusions SLJ performance among Chinese children and adolescents has generally declined in recent decades. The decline was particularly marked among boys and high school students, indicating a narrowing of the sex and age gaps. These findings underscore the critical need for sex- and age-tailored interventions and programs designed to enhance muscular fitness.