Evaluation report

Feasibility and Preliminary Effectiveness of a School-Based Speed- Related Fitness Program in Primary School Children: A Large Quasi-Experimental Study

Zhu J, Zhao M, Xu L, Song Z, Bu Y · 29 Jun 2026

Abstract

Abstract Background Speed-related fitness is an important component of children's health- and skill-related physical fitness and is routinely monitored in Chinese schools through the 50-m sprint. Speed, agility, and quickness (SAQ) training offers a framework for organizing speed-related learning tasks, but most evidence comes from youth athletes rather than ordinary primary school children, and pragmatic school-based evidence is scarce. Objective To evaluate the feasibility and preliminary effectiveness of an 8-week physical-education-embedded SAQ program for improving 50-m sprint performance in primary school children. Methods In this large two-group pretest-posttest quasi-experimental study with intact-class allocation in one primary school in Sichuan Province, China, 1,254 children (627 SAQ group; 627 routine physical education control group) completed paired 50-m sprint assessments. The SAQ group received 16 sessions (twice weekly, about 35 min) of equipment-light, progressively organized SAQ activities embedded in regular physical education. The primary outcome was 50-m sprint time. Analyses included paired and independent-samples comparisons, ANCOVA with robust standard errors adjusting for baseline time, age, and sex, linear mixed-effects and cluster-robust models using grade cohort as the higher-level grouping, baseline-stratified analyses, and a responder analysis. Results Groups were comparable at baseline in age, sex, grade, and 50-m time (all p > 0.40). The SAQ group improved by 0.41 s (95% CI 0.34 to 0.49; dz = 0.44), whereas the control group did not change appreciably (0.06 s; 95% CI -0.02 to 0.13). The between-group difference in improvement was 0.36 s (95% CI 0.25 to 0.47; p < 0.001; Hedges g = 0.37). After adjustment for baseline time, age, and sex, posttest time remained lower in the SAQ group (β = -0.36 s; 95% CI -0.44 to -0.28; p < 0.001), and the effect was consistent across adjusted models, exploratory grade-cohort analyses, and outlier-excluded sensitivity analyses; however, grade cohort was treated only as an approximate higher-level grouping because class identifiers were unavailable. More SAQ children were positive responders (70.3% vs 51.4%; odds ratio 2.25; 95% CI 1.78 to 2.83) and meaningful responders (improvement ≥ 0.30 s: 58.7% vs 35.6%; odds ratio 2.57; 95% CI 2.05 to 3.23). The intervention-associated benefit was present across baseline-speed strata, sexes, and grades, with the largest standardized difference among children with intermediate baseline speed. Conclusion An 8-week physical-education-embedded SAQ program was associated with greater improvement in 50-m sprint performance than routine physical education among primary school children. These findings provide preliminary, pragmatic evidence that equipment-light, progressively organized SAQ activities may be a feasible approach to support speed-related fitness in real-world school physical education. Cluster-randomized trials with broader motor, fitness, and psychosocial outcomes and longer follow-up are needed to confirm effectiveness, mechanisms, and sustainability.