Engineering Online and In-Person Social Networks for Physical Activity: A Randomized Trial

Abstract

Background: Social networks can influence physical activity, but little is known about how best to engineer online and in-person social networks to increase activity.

Purpose: The purpose of this study was to conduct a randomized trial based on the Social Networks for Activity Promotion model to assess the incremental contributions of different procedures for building social networks on objectively measured outcomes.

Methods: Physically inactive adults (n = 308, age, 50.3 (SD = 8.3) years, 38.3 % male, 83.4 % overweight/obese) were randomized to one of three groups. The Promotion group evaluated the effects of weekly emailed tips emphasizing social network interactions for walking (e.g., encouragement, informational support); the Activity group evaluated the incremental effect of adding an evidence-based online fitness walking intervention to the weekly tips; and the Social Networks group evaluated the additional incremental effect of providing access to an online networking site for walking as well as prompting walking/activity across diverse settings. The primary outcome was mean change in accelerometer-measured moderate-to-vigorous physical activity (MVPA), assessed at 3 and 9 months from baseline.

Results: Participants increased their MVPA by 21.0 min/week, 95 % CI [5.9, 36.1], p = .005, at 3 months, and this change was sustained at 9 months, with no between-group differences.

Conclusions: Although the structure of procedures for targeting social networks varied across intervention groups, the functional effect of these procedures on physical activity was similar. Future research should evaluate if more powerful reinforcers improve the effects of social network interventions.

Trial registration number: The trial was registered with the ClinicalTrials.gov (NCT01142804).

Keywords: Clinical trial; Environment; Exercise; Social media; Social support; Walking.

Conflict of interest statement

Liza S. Rovniak, Lan Kong, Melbourne F. Hovell, Ding Ding, Chester A. Ray, Jennifer L. Kraschnewski, Stephen A. Matthews, Elizabeth Kiser, Vernon M. Chinchilli, Daniel R. George, and Christopher N. Sciamanna declare that they have no conflict of interest. James F. Sallis has received grants from Nike Inc, royalties from San Diego State University Foundation, consulting fees from SPARK Programs of Sportime Inc, and is a stockholder in Santech Inc. Conflict of Interest Dr. Sallis reports disclosures (please see attached); all other authors declare that they have no conflicts of interest.

Figures

Figure 1

Social Networks for Activity Promotion (SNAP) model and intervention procedures. Note. This study tested the incremental effects of different intervention procedures that placed more vs. less emphasis on each ecological level, while acknowledging that all ecological levels interact. Intervention procedures most relevant to each ecological level are highlighted in italics. aIn addition to the contacts with program staff resulting from engagement in walking, evidence suggests that participants who walk in public settings may incidentally come into contact with other people who could reinforce their walking (e.g., pleasant conversations with neighbors, shopkeepers, or gym staff) [10, 12]. However, this program did not formally arrange these social contacts. bWe hypothesized that the program-provided social network interactions would function to prompt and reinforce walking. However, other family/friend social network interactions could function to discourage walking (e.g., criticism for walking) [10, 11].

Figure 2

Consort diagram: flow of participants through trial.

Figure 3

Mean change (estimate [95% CI]) in physical activity outcomes for subgroups with lower (n = 101) vs. higher (n = 189) moderate-to-vigorous physical activity (MVPA) at baseline. a indicates a significant change from baseline. b indicates a significant change between the 3 to 9 month assessments. There were no significant differences in the distribution of Lower vs. Higher Activity participants by treatment condition. The proportion of Lower Activity participants was 32.6% in the Promotion condition, 33.0% in the Activity condition, and 38.8% in the Social Networks condition (Pearson Chi-Square, p = .60).

Figure 4

Parts A and B: Percentage of participants in Social Networks group participating at least once in online and in-person activities to build social networks for physical activity, during 12-week program (n = 104). All activities self-reported weekly by participants. Data for all online networking activities, and for attending the staff-led “Meet the Group” walks were also tracked weekly by program staff; staff-provided data for these outcomes are used here. Parts C and D: Percentage of participants at 3-month assessment (n = 270) reporting that they “agreed” or “strongly agreed” that they had received/used specific program components. Data for attendance at the introductory skill training session were provided/tracked by program staff. All participants attended this session, except for three participants who dropped out immediately post-randomization. a indicates a significant difference between the Social Networks (reference category) and the Activity groups (OR = .52, 95% CI [.27, .98]). b indicates a significant difference between the Social Networks (reference category) and the Promotion groups (OR = .41, 95% CI [.21, .81]).