# Factors associated with device-based measured physical activity and sedentary behavior in a cross-sectional citizen science study of adolescents during the COVID-19 pandemic

## TL;DR

This study explores factors linked to physical activity and sedentary behavior in adolescents during the pandemic using a citizen science approach.

## Contribution

The study uses co-created questionnaires with adolescents to identify novel factors influencing physical activity.

## Key findings

- High traffic safety around schools and higher degree school types were linked to more moderate-to-vigorous physical activity.
- Feeling exhausted after school reduced physical activity, while internal motivation and active hobbies increased it.
- Female sex was associated with lower sedentary time, but other factors were not significantly linked to sedentary behavior.

## Abstract

Insufficient physical activity (PA) and extensive sedentary behavior (SB) in adolescents has been related to adverse outcomes related to physical fitness, body weight as well as social and psychological health indicators. Furthermore, these behaviors tend to track from adolescence to adulthood, thereby affecting adult chronic disease risk. The knowledge of factors associated with PA and SB is needed particularly in adolescents, in order to plan public health strategies aiming at increasing PA and reducing SB. The aim of this Citizen Science project (conducted between February 2020 and June 2021) was to work together with young citizens on a school-based epidemiologic study assessing device-based measured PA and SB in students (grades 8 or higher) to identify associated factors based on both established as well as co-created questionnaires.

In 12 school classes from Berlin and Brandenburg, students were as Citizen Scientists involved in the co-creation of class-specific questionnaires by collecting factors that may influence their PA and SB. Students participating in the study wore thigh-worn accelerometers (activPAL) for seven consecutive days and subsequently completed established as well as the newly developed class-specific questionnaires to ascertain potential influencing factors of PA and SB. Multilevel linear regression models were used to identify factors associated with time spent in moderate-to-vigorous physical activity (MVPA) and SB.

Accelerometry data with at least four recorded days were available for 119 students (783 recorded days). In models adjusted for age, sex and parental socioeconomic status, high traffic safety around the school (14.8 min/day, 95% CI 0.9, 28.7) and higher degree school type (10.7 min/day, 95% CI 1.7; 19.8) were associated with more time spent in MVPA. From the class-specific questionnaires developed based on input from students, the feeling of being exhausted after school and homework was associated with less time spent in MVPA, while internal motivation to be physically active, active hobbies and working out regularly at a gym were associated with more time spent in MVPA. The potential influencing factors under investigation were not associated with sedentary time (except female sex, which was related to lower sedentary time).

Although our findings warrant confirmation in larger samples, this Citizen Science study points to potential action points that may be targeted in public health interventions aimed at increasing PA to improve health in adolescents.

The online version contains supplementary material available at 10.1186/s12889-025-25776-5.