Comparison of body mass index and physical fitness activity results of middle school students before and after the covid-19 pandemic and evaluation using survey results

BACKGROUND: This study aimed to examine changes in body mass index (BMI) and selected physical fitness parameters (push-ups, sit-ups, and right–left flexibility) among middle school students across three distinct periods; pre-pandemic, early post-pandemic, and late post-pandemicand to evaluate whether the negative effects of the COVID-19 pandemic persisted over time. Differences according to gender, grade level, and academic term were also analyzed, together with survey-based lifestyle indicators collected in the post-pandemic period. METHODS: A longitudinal observational design was used. Physical fitness test data obtained during Physical Education and Sports classes were retrospectively and prospectively analyzed for three academic years: 2017–2018 (pre-COVID period), 2021–2022 (early post-COVID period), and 2022–2023 (late post-COVID period). The sample consisted of 1,771 students aged 9–13 years from grades 5 to 8. Measurements included height, weight, BMI, push-up, sit-up, and right–left flexibility tests. In addition, a post-pandemic lifestyle survey was administered via Google Forms. Non-parametric statistical tests (Kruskal–Wallis, Mann–Whitney U, and Wilcoxon signed-rank tests) were applied, with statistical significance set at p < 0.05. RESULTS: Significant differences were observed in physical fitness and anthropometric parameters across periods. Compared with the pre-pandemic period, students in the early post-pandemic period showed higher body weight and BMI values, alongside marked declines in muscular strength and flexibility. Although partial recovery was observed in the late post-pandemic period, most physical fitness parameters did not return to pre-pandemic levels. Survey findings indicated changes in dietary habits and physical activity patterns; however, no statistically significant association was found between fast-food consumption frequency and academic performance. CONCLUSIONS: The findings indicate that the COVID-19 pandemic had lasting negative effects on physical fitness and BMI among middle school students. Although some improvements were evident over time, recovery remained incomplete. These results highlight the importance of structured school-based physical activity programs and proactive planning to mitigate the adverse effects of potential future pandemics.