title: A daily process analysis of intentions and physical activity in college students.
abstract: Social-cognitive theories, such as the theory of planned behavior, posit intentions as proximal influences on physical activity (PA). This paper extends those theories by examining within-person variation in intentions and moderate-to-vigorous physical activity (MVPA) as a function of the unfolding constraints in people's daily lives (e.g., perceived time availability, fatigue, soreness, weather, overeating). College students (N = 63) completed a 14-day diary study over the Internet that rated daily motivation, contextual constraints, and MVPA. Key findings from multilevel analyses were that (1) between-person differences represented 46% and 33% of the variability in daily MVPA intentions and behavior, respectively; (2) attitudes, injunctive norms, self-efficacy, perceptions of limited time availability, and weekend status predicted daily changes in intention strength; and (3) daily changes in intentions, perceptions of limited time availability, and weekend status predicted day-to-day changes in MVPA. Embedding future motivation and PA research in the context of people's daily lives will advance understanding of individual PA change processes.
authors.affiliation: Department of Kinesiology and with the Department of Human Development and Family Studies, Pennsylvania State University, University Park, Pennsylvania.
authors.forename: David E
authors.initials: DE
authors.lastname: Conroy
authors.forename: Steriani
authors.initials: S
authors.lastname: Elavsky
authors.forename: Shawna E
authors.initials: SE
authors.lastname: Doerksen
authors.forename: Jaclyn P
authors.initials: JP
authors.lastname: Maher
mesh_terms: D005260:Female; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D033182:Intention; D007389:Internal-External Control; D008297:Male; D009042:Motivation / Q000502:physiology; D009043:Motor Activity / Q000502:physiology*; D020377:Self Efficacy; D013334:Students / Q000523:psychology* / Q000706:statistics & numerical data