A glimpse into the impact of physical activity on linear growth in children and adolescents through activity restrictions accompanying the COVID-19 outbreak.

Background: Linear growth in children and adolescents, a key health indicator, is influenced by various factors, including physical activity (PA). The COVID-19 lockdown in Taiwan created a unique opportunity to examine the effect of PA restrictions on growth. Methods: This retrospective cohort study was conducted at two hospitals in central Taiwan. The study included 72 children and adolescents (26 males, 46 females) who attended a growth clinic. Height and weight measurements were recorded in three stages: pre-lockdown, during lockdown, and post-lockdown. Growth rates were compared across stages using paired t-tests. Results: The average growth rate was lowest during lockdown (0.0181 cm/day) and highest pre-lockdown (0.0198 cm/day), although the difference was not statistically significant. In males, growth rates significantly increased post-lockdown compared to those during lockdown (p = 0.04), while no significant differences were observed in females across stages. Conclusion: PA positively influences linear growth in children, with a more pronounced effect in boys. Lockdown restrictions led to reduced PA, particularly impacting boys' growth rates. These findings emphasize the importance of PA for healthy growth in children, especially under restrictive conditions, and suggest the need to further encourage active lifestyles among children, particularly girls.