ACKNOWLEDGMENTS

1. BACKGROUND • Total minutes in MVPA were calculated within the 2 hours after the intention, self-efficacy, and outcome expectancy questions were answered by participants. • Three multilevel models controlling for clusters within individuals were fit using prompt-level intention/self-efficacy/outcome expectancy as the predictor, separately, and total MVPA minutes in the next 2 hours as the outcome. • All models controlled for age, gender, weight status, household income, weekend/weekday, and individuals’ overall average daily intention/self-efficacy/outcome expectancy scores. Intention, self-efficacy, and outcome expectancy are recognized as important cognitive determinants for physical activity (PA). However, few studies have examined the near-time (i.e., within a few hours) effects of these cognitive determinants on PA partially due to the difficulty in assessing intention, self-efficacy, and outcome expectancy in real-time under naturalistic conditions. beta coef. = 1.13 Figure 3. Prompt-level intention predicting total MVPA minutes in the following 2-hour period RESEARCH OBJECTIVE beta coef. = 1.01 The current study used Ecological Momentary Assessment (EMA) to examine whether intention, self-efficacy, and outcome expectancy predict physical activity levels in the next 2 hours during the course of adults’ everyday life; and determine which of the three cognitive factors is a stronger predictor of the subsequent physical activity levels. Figure 4. Prompt-level self-efficacy predicting total MVPA minutes in the following 2-hour period Examining the Immediate Effects of Intention and Self-Efficacy on Physical Activity among Adults: An Ecological Momentary Assessment StudyYue Liao, MPH, CPH; Jimi Huh, PhD; Donna Spruijt-Metz, PhD, Stephen Intille, PhD; Mary Ann Pentz, PhD; Genevieve Dunton, PhD, MPHInstitute for Health Promotion & Disease Prevention ResearchDepartment of Preventive Medicine, Keck School of Medicine, University of Southern California • A follow-up analysis including both intention and self-efficacy in the multilevel model showed that only self-efficacy remained significant in predicting subsequent total MVPA minutes (beta coef. = 1.74, p = .04), suggesting that self-efficacy might be a stronger cognitive determinant than intention and outcome expectancy. EMA Prompt Total MVPA Minutes EMA Prompt Total MVPA Minutes EMA Prompt Total MVPA Minutes EMA Prompt Total MVPA Minutes 9:30am 9:30-11:30am 12:50pm 12:50-2:50pm 4:35pm 4:35-6:35pm 7:20pm 7:20-9:20pm METHODS CONCLUSIONS Figure 2. Illustration of time-matched EMA and activity assessment • Participants were monitored for 4 days (Saturday – Tuesday) wearing a mobile phone (T-Mobile Shadow) and an accelerometer (Actigraph GT2M) during their waking hours. • Electronic surveys delivered by mobile phones assessed intention, self-efficacy (2 questions), and outcome expectancy (4 questions) in physical activity 4 times a day at random intervals throughout the day. • Physical activity level was measured by accelerometer and converted to moderate-to-vigorous physical activity (MVPA) minutes. • Adults who had greater intention and self-efficacy for physical activity relative to their usual level engaged in more MVPA minutes in the following 2-hr period. • Ecological Momentary Interventions might consider using strategies to increase adults’ self-efficacy state to promote physical activity level on a within-day basis. • Future studies could examine what other factors moderate the effects of cognitive determinants on subsequent physical activity (e.g., assessing stage of change, mood). PARTICIPANTS • 110 adult residents from San Bernardino County, California. • 72% females and 30% Hispanic. • Ages 27 – 73 (M = 40). • 62% were overweight/obese. RESULTS ACKNOWLEDGMENTS • Greater intention and self-efficacy relative to one’s usual (average) level were associated with more total MVPA minutes in the following 2-hour period (p’s<.05, see Figure 3 & Figure 4). • Outcome expectancy was not related to the subsequent MVPA minutes. Funded by: American Cancer Society 118283-MRSGT-10-012-01-CPPB (Dunton, PI) and National Cancer Institute R01-CA-123243 (Pentz, PI). Contact information: Yue Liao, MPH, University of Southern California. 2001 N. Soto Street, Institute of Preventive Research Alhambra, CA 90033 yueliao@usc.edu Figure 1. Screen shots of sample EMA questions