SmartMoves: A Prospective Observational Study of Mood, Motivation, and Physical Activity

Physical activity (PA) is a key determinant of health promotion and disease prevention, yet physical inactivity remains a pervasive global health challenge. Despite well-documented physical and mental health benefits (Perry et al., 2023; Teychenne et al., 2025), adherence to PA guidelines among adults remains low. Approximately 31% of adults globally do not meet the World Health Organization (WHO) recommendation of 150 minutes per week, and this proportion has increased in recent decades (Strain et al., 2024). In Canada, only 46% and 35% of adults meet aerobic and muscle-strengthening guidelines, respectively (ParticipACTION, 2025). University students are not exempt from this trend, with approximately 42% classified as insufficiently active (Pengpid et al., 2015). This is particularly concerning given the elevated psychological distress often experienced during the transition to adulthood, and the protective role PA may play in mental health (Santana et al., 2023). Because health behaviors established in young adulthood often track into later life, understanding determinants of PA in this population remains a public health priority (van Sluijs et al., 2021). Social cognitive and motivational theories such as the theory of planned behavior (TPB) and social cognitive theory (SCT) have been widely applied to explain PA behavior (Rhodes and Brennan, 2026). Across these frameworks, intention typically emerges as a proximal predictor of behavior. However, the well-established “intention–behavior gap” highlights that strong intentions do not consistently translate into action (Feil et al., 2023; Rhodes et al., 2022). Much of the existing literature relies on static, between-person designs that contrast individuals with relatively high versus low levels of intentions, self-efficacy, or attitudes (Phipps et al., 2021). Such approaches overlook dynamic within-person fluctuations in affect, motivation, self-regulation, and context that may influence whether PA occurs at a given moment (Dunton, 2017). Capturing these real-time processes may help clarify when and why individuals translate intentions into behavior (Haag et al., 2025; Maher et al., 2017). Ecological momentary assessment (EMA) provides a methodological approach to address these limitations. EMA involves repeated real-time assessments of experiences and behaviors in naturalistic settings, typically via smartphone-based surveys (Stinson et al., 2022). Compared with retrospective questionnaires, EMA reduces recall bias and enhances ecological validity, while enabling the examination of both within- and between-person associations (Dunton, 2017). Emerging EMA research suggests that momentary fluctuations in affect, stress, self-efficacy, and perceived barriers are associated with corresponding changes in PA (Dunton et al., 2018; Hevel & Maher, 2025). However, many EMA studies remain theoretically fragmented, drawing selectively from multiple frameworks without grounding measurement and interpretation within a coherent theoretical model (Maes et al., 2022). The Multi-Process Action Control (M-PAC) framework offers a comprehensive structure for examining PA behavior. M-PAC proposes that PA adoption and maintenance are governed by reflective processes (e.g., attitudes, perceived capability), regulatory processes (e.g., planning, self-monitoring), and reflexive processes (e.g., habit, identity) (Rhodes, 2021). Although the framework was developed to explain the intention–behavior gap and inform intervention design, applications have largely relied on traditional survey methods (Porter et al., 2024; Tang et al., 2023). Recent theoretical work suggests that M-PAC constructs may vary in their temporal dynamics, with some processes demonstrating substantial within-person fluctuation across contexts and time (Rhodes & Kwan, 2025). Preliminary EMA research applying an M-PAC lens has shown associations between state motivation, habitual patterns, and PA in adolescents (Harris et al., 2024), warranting further investigation in university populations. The purpose of this study is to apply the M-PAC framework within a prospective design incorporating ecological momentary assessment to investigate both between- and within-person determinants of intention follow-through and subsequent physical activity among university students. Based on the M-PAC framework, we hypothesize that regulatory and reflexive processes will be positively associated with intention follow-through and physical activity at both the between-person and within-person levels. We further explore whether affective variables, window of opportunity, emotion regulation, self-congruence, and anticipated regret are associated with these outcomes.