JMIR Publications

ABSTRACT

Background:

Despite the health benefits of engaging in regular physical activity (PA), the majority of American adults do not meet the PA guidelines for aerobic and muscle-strengthening activities. Self-efficacy, the belief that one can execute specific actions, has been suggested to be a strong determinant of PA behaviors. With the increasing availability of digital technologies, collecting longitudinal real-time self-efficacy and PA data has become available. However, evidence in longitudinal real-time assessment of self-efficacy in relation to objectively measured PA is scarce.

Objective:

This study aimed to examine a novel approach to measure individuals' real-time weekly self-efficacy in response to their personalized PA goals and performance over the 12-week intervention period in community-dwelling women who were physically inactive.

Methods:

In this secondary data analysis, 140 women who received a 12-week PA intervention were asked to report their real-time weekly self-efficacy via a study mobile application. PA (daily step counts) was measured by an accelerometer every day for 12 weeks. We used a logistic mixed model of the 12 weekly PA on the outcome of self-efficacy, controlling for potential confounders of age, body mass index, self-reported white, having a college education or higher, being married, and being employed.

Results:

The mean age with standard deviation (SD) was 52.7 (11.5) years with a range of 25 to 68 years. Descriptive analyses showed the dynamics of real-time weekly self-efficacy and weekly step goal success. Participants were more likely to be confident in meeting weekly step goals in the beginning week of the intervention but gradually less confident throughout the intervention. For instance, the majority (74.4%) of participants reported to be confident in the first week, whereas less than half (46.4%) reported confidence in the final week of the intervention. Participants who successfully met weekly step goals were 4.41 times more likely to be confident about achieving the following week's step goals compared to those who did not meet weekly step goals (adjusted OR=4.41; 95% CI: 2.59 to 7.50; P < .001). The significant association between real-time self-efficacy and weekly step goal success was confirmed in a series of sensitivity analyses, including 7 logistic mixed models and 1 multinomial mixed model.

Conclusions:

This study demonstrates the potential utility of a novel approach to examine self-efficacy in real time, for analysis of self-efficacy in conjunction with objectively measured PA. Discovering the dynamic patterns and changes in weekly self-efficacy and PA behaviors within participants and between participants may aid in designing a more personalized PA intervention than programs that are currently available. Evaluation of this novel approach in an RCT is warranted.