Longitudinal changes in objectively-measured physical activity and sedentary time among school-age children in Central Texas, US during the COVID-19 pandemic.

Background: Most available evidence on the effects of the COVID-19 pandemic on child movement behaviors is from cross-sectional studies using self-report measures. This study aimed to identify change trajectories and their associated factors for objectively-assessed physical activity and sedentary time among an ethnically and socioeconomically diverse sample of school-age children from Central Texas, U.S.A., during COVID-19.

Methods: Pre- (Sept. 2019 - Feb. 2020) and during- (Oct. 2020 - March 2021) COVID-19 physical activity and sedentary behavior data were collected for school-age children (8-11 years) enrolled in the Safe Travel Environment Evaluation in Texas Schools (STREETS) cohort study. Daily time spent in moderate- to vigorous-intensity physical activity (MVPA) and sedentary time were assessed using GT3X-wBT Actigraph accelerometers. Parent surveys were used to assess socio-ecological factors. Latent class linear mixed models were used to identify change trajectories of MVPA and sedentary time. Logistic regression models were used to assess the association between socio-ecological characteristics with physical activity and sedentary time change trajectory groups.

Results: There was a significant decrease in mean daily MVPA (- 9.4 mins, SD = 18.54) and an increase in sedentary behavior (0.83 hrs, SD = 1.18). Two trajectory groups were identified for MVPA ('decrease MPVA' and 'maintain high MVPA'), with the majority (82.1%) being in the 'decrease MVPA' group. Three trajectory groups were identified for sedentary behavior ('moderate increase sedentary, 'steep increase sedentary,' and 'decrease sedentary'), with most children (78.5%) being in the 'moderate increase' group. Girls had significantly lower odds of being in the 'maintain high MVPA' group than boys (OR = 0.27, 95% CI = 0.11, 0.61). Children living in neighborhoods with higher perceived social cohesion had significantly higher odds of being in the 'maintain high MVPA' group (OR = 1.22, 95% CI = 1.06, 1.41), while those in neighborhoods with higher social cohesion had lower odds of being in the 'decrease sedentary' group (OR = 0.86, 95% CI = 0.74, 0.99).

Conclusions: Declines in physical activity and increases in sedentary time among most school-age children during COVID-19 in a socioeconomically and ethnically diverse U.S. sample, were observed in our study, especially among girls. These findings highlight the need to counteract the short-term negative changes in movement behaviors in response to COVID-19 among children.