Physical activity (PA) in children and adolescents provides immediate and long-term benefits(Chaput et al., 2020; Downing et al., 2021; Piercy et al., 2018). The World Health Organization (WHO) recommends children and adolescents perform moderate-to-vigorous physical activity (MVPA) for ≥60 min per day (WHO Guidelines on Physical Activity and Sedentary Behaviour, 2020). However, recent studies showed that >80% of adolescents aged 11–17 years worldwide did not meet international recommendations (Guthold et al., 2020). Similarly, a 2017 national survey in China showed that the prevalence of physical inactivity among children and adolescents was as high as 65.9% (Zhu et al., 2019). Although some school-level interventions have been implemented, such as improving the quality of physical education classes and PA-focused after-school programs, overall, no noticeable effects have been found (Love et al., 2019; Messing et al., 2019). The latest literature has shown little effect in 89 school-based randomized controlled trials worldwide, with 66,752 children and adolescents (aged 6–18 years) enrolled in daily MVPA (Neil-Sztramko et al., 2021). Also, studies have confirmed that participation in structured physical activities, such as physical education, does not promote PA among young people (Bélanger et al., 2009). After school time, when young people engage in a significant proportion of their daily leisure activities, is a predictor of overall activity patterns (van Sluijs et al., 2007). In the most recent high-quality studies, leisure-time PA is recognized as the dominant indicator of the overall PA for children (Bauman et al., 2012). Carlson et al. found a large percentage of adolescents' exercise time occurred outside of school when using Global Positioning System (Carlson et al., 2016). Thus, investigating PA outside of school among children and adolescents is critical.

Since multiple factors may influence motor behavior, understanding the barriers and facilitators is pivotal in guideline implementation in out-of-school settings. Recent meta-analyses of out-of-school PA interventions have shown no significant effect of the social cognitive theory and behavioral change theory in children and adolescents. A possible explanation for this is that the theories are loosely structured, resulting in obscure pathways to guide interventions, and the optimal theoretical frameworks may not have been adequately selected or applied (Mears and Jago, 2016; Tapia-Serrano et al., 2023). Problem Behavior Theory (PBT), a psychosocial theory originally coined by Richard Jessor, is now widely used to explore the factors influencing health-hazardous behaviors among young people, such as regular PA (Cai et al., 2015; Donovan et al., 1991; Hays et al., 1987). Jessor suggests that individual behaviors depend on the interaction between personal and environmental factors and maladaptive behaviors (Jessor, 2018). Unlike most previous observational studies, which only examined a single and isolated perspective, the PBT takes a holistic view of the complexity of the interactions between various factors, providing a comprehensive assessment.

According to the PBT theoretical framework (Jessor, 1991), children's and adolescents' out-of-school PA may be influenced by multiple dimensions of personality, perceived environment, and behavior. At the level of the personality system, intrinsic motivation, the intrinsic drive to satisfy basic psychological needs in a given activity, has been shown to positively contribute to in-school and out-of-school PA (Deci and Ryan, 2000). Similarly, academic stress, a common problem for students, has also been shown to be associated with PA, particularly in Asians (Yang et al., 2022). As for the perceived environment system, parental support plays a crucial role in promoting PA among children and adolescents in various settings (Messing et al., 2019). Several studies have indicated positive correlations between parental encouragement, companionship, financial support, participation, and role modeling in PA and high participation in a child's MVPA (Liu et al., 2017; Wang et al., 2017). Moreover, the availability and accessibility of green spaces, parks, and recreational facilities in the community are important determinants of PA participation among Chinese children and adolescents (An et al., 2019). Regarding the behavior system, modifiable health risk behaviors, such as poor dietary habits, sleep deficit, and prolonged screen time (ST), are often linked to physical inactivity (Bae et al., 2020; Cai et al., 2015; Hays et al., 1987).

The purpose of this study was to investigate PA in children and adolescents and to explore out-of-school PA correlates based on the PBT framework. In addition, this study employs structural equation modeling (SEM) to determine the association between the three systems of PBT and out-of-school PA among Chinese children and adolescents.