Momentary physical activity intentions most strongly predict subsequent movement when a person’s self-regulatory capacity is lower than usual or generally low, acting as a compensatory mechanism rather than an augmenting one, according to an observational ecological momentary assessment study of young adults.
The investigation addressed the recognized intention-behavior gap in physical activity, where stated goals fail to translate into action at the momentary level. Researchers evaluated whether time-invariant self-regulatory traits—including behavioral inhibition and activation system sensitivities, trait self-control, and physical activity self-regulatory strategies—alongside time-varying momentary states like feeling focused, feeling in control, and procrastinating, moderated the within-day coupling between momentary intentions and subsequent movement.
The study protocol tracked 228 young adults between the ages of 18 and 29 over a 12-month period. Participants completed hourly, signal-contingent mobile ecological momentary assessment surveys that recorded their intentions to engage in physical activity during the subsequent 60 minutes across repeated four-day monitoring periods, while continuous movement intensity was captured using wrist-worn accelerometers across 20,491 total paired observations.
To analyze the nested observational data, the authors applied multilevel Gamma models that decomposed intention and moderator variables into distinct between-person and within-person components. In 13 of the 14 tested models, within-person momentary intentions consistently predicted significantly greater accelerometer-measured movement in the 60 minutes following the survey prompt (p ≤ .002).
Seven of the 14 tested moderators yielded statistically significant interaction terms at p < .01, spanning seven distinct self-regulatory constructs. Trait behavioral inhibition, physical activity self-monitoring, and time management moderated the between-person intention-activity association, reflecting for whom an overall tendency to form intentions produced greater physical activity. Conversely, social support and self-reinforcement moderated the within-person association, momentary focus moderated the within-person relationship at the occasion level to indicate when intentions were most predictive, and momentary procrastination moderated the between-person association.
Crucially, all seven significant interaction effects operated in a compensatory manner, meaning the association between intentions and subsequent physical activity was strongest among individuals with lower self-regulatory capacity and during specific occasions when an individual’s capacity dipped below their typical baseline. The authors concluded that momentary intentions may provide an alternative cognitive pathway to activity when self-regulatory resources are depleted, suggesting that just-in-time mobile interventions targeting intention formation during moments of personal self-regulatory vulnerability could help support physical activity.
In the study design, 228 young adult participants aged 18 to 29 completed hourly, signal-contingent mobile ecological momentary assessment surveys across four-day monitoring periods repeated over twelve months. Each mobile survey prompt assessed intentions for physical activity in the next 60 minutes. These momentary assessments were paired directly with wrist-worn accelerometry measuring movement intensity, accumulating 20,491 total observations. The investigation evaluated whether self-regulatory factors clarify for whom and when momentary physical activity intentions translate into behavior, focusing on the within-day association between momentary intentions and subsequent accelerometer-measured physical activity over each 60-minute window.
The researchers applied multilevel Gamma models to analyze the data, decomposing intention and moderator variables into distinct between-person and within-person components. Across 13 of the 14 tested models, within-person intention consistently predicted greater subsequent movement in the 60 minutes following each mobile prompt at p ≤ .002. This statistical decomposition allowed the authors to address the intention-behavior gap by separating whether intentions operated as between-person differences or within-person momentary dynamics across repeated daily observations.
The analysis examined whether the within-day coupling between intentions and physical activity was moderated by time-invariant self-regulatory traits and time-varying momentary states. The time-invariant traits evaluated included behavioral inhibition system sensitivity, behavioral activation system sensitivity, trait self-control, and physical activity self-regulatory strategies, including self-monitoring, time management, social support, and self-reinforcement. The time-varying momentary states assessed during the hourly surveys included feeling focused, feeling in control, and procrastinating. Across these measures, seven of fourteen moderators produced a significant interaction at p < .01, with one significant term emerging from each of the seven moderator constructs.
The significant interaction terms revealed specific patterns across the between-person and within-person levels of analysis. Trait behavioral inhibition, physical activity self-monitoring, and time management moderated the between-person intention-activity association, indicating for whom a higher overall rate of intending translated into greater activity. Social support and self-reinforcement moderated the within-person intention-activity association, indicating for whom momentary intentions more strongly predicted subsequent activity. Furthermore, momentary focus moderated the within-person association at the occasion level, indicating when within a person intentions were more predictive, while momentary procrastination moderated the between-person association.
All seven observed interaction effects functioned in a compensatory rather than augmenting direction. Specifically, the association between momentary intentions and subsequent physical activity was strongest among individuals lower in self-regulatory capacity, as well as on specific occasions when a person’s momentary capacity was lower than usual. Based on these findings, the authors suggested that momentary intentions can serve as an alternative route to activity when self-regulatory capacity is low. They concluded that just-in-time intervention strategies that support the formation of momentary intentions among individuals and moments of greatest self-regulatory vulnerability may be useful for improving physical activity.
Subject of Research: Self-regulatory moderators of momentary physical activity intentions and movement in young adults
Article Title: Self-regulatory moderators of the intention–behavior gap in physical activity: an ecological momentary assessment study among young adults
Article References: Samuelson, M., Wang, W.-L., Li, J., Hedeker, D., Rothman, A. J., Intille, S. S., Sheeran, P., Dunton, G. F., & Mason, T. B. (2026). Self-regulatory moderators of the intention–behavior gap in physical activity: an ecological momentary assessment study among young adults. Frontiers in Digital Health, 8, Article 1924099. https://doi.org/10.3389/fdgth.2026.1924099
Image Credits: AI Generated
DOI: 10.3389/fdgth.2026.1924099
Keywords: physical activity, intention-behavior gap, ecological momentary assessment, accelerometry, self-regulation, young adults, behavioral inhibition system, behavioral activation system, trait self-control, time management, self-monitoring, social support, self-reinforcement, momentary focus, procrastination, multilevel Gamma models, just-in-time adaptive interventions, movement intensity