Developmental trajectories of physical fitness and health and their influencing factors among primary school students in Suzhou, China (2015–2023): an accelerated longitudinal study
Year: 2026
Type: article
Abstract: Background This study characterized developmental trajectories of physical fitness and health among primary school students, identified latent trajectory subgroups, and examined associations with sex, baseline weight status and the COVID-19 pandemic. Methods We analyzed mandatory annual National Student Physical Fitness Standard test records of students in grades 1–6 at five primary schools in Suzhou, China (2015–2023). After linking records across student-ID changes, 8,280 records from 2,238 students formed an accelerated longitudinal design. A three-level growth model with a piecewise term at 2020, using grade as the developmental axis and calendar year as a period covariate, described the average trajectory of the total score. Group-based trajectory modeling (GBTM) identified latent classes, and multinomial logistic regression examined their predictors. Sensitivity analyses examined cohort splice-ability, attrition, breakpoints, classification uncertainty and the scored body mass index (BMI) item. Results The total score declined across grades (−0.73 per grade, P < 0.001), but within-student scores were stable before 2020 (+0.29 per year, P = 0.14) because a positive period trend offset this decline; cohort splice-ability was only partly supported. From 2020, the period trend changed from +1.02 to −1.35 points per year ( P < 0.001); breakpoints in 2021–2022 fitted better. Girls scored higher than boys on this sex-specific composite (+2.80, P < 0.001). Students with obesity scored 6.99 points lower than normal-weight peers ( P < 0.001), about two-thirds of which reflected the scored BMI item. GBTM identified four classes: persistently low (11.4%), below-average declining (33.4%), good-but-declining (35.7%) and high-then-declining (19.6%) (average posterior probabilities 0.80–0.90). Relative to the good-but-declining class, girls were less likely to belong to the lower-level classes, whereas baseline overweight/obesity was associated with the persistently low (OR = 5.25) and below-average declining (OR = 2.42) classes. Conclusions Scores were stable within students before 2020 and declined thereafter, coinciding with the pandemic period; the decline across grades depends on how developmental and period effects are separated. Trajectories were heterogeneous, and baseline overweight/obesity was associated with weaker trajectories beyond the scored BMI item. Early identification and targeted intervention should prioritize students in the persistently low and high-then-declining classes.
Source: Frontiers in Public Health
Language: English
Topic: Physical Activity and Health
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7225806522