EVALUATION OF AN INTERNET, STAGE-BASED PHYSICAL ACTIVITY INTERVENTION

Abstract

The purpose of this study was to evaluate the effect of online, stage-based materials on exercise behavior and stage of readiness to change. Subjects were 525 employees of a large university. Subjects completed a baseline questionnaire, which included a staging algorithm to stage subject's exercise behavior. Subjects were randomly assigned to one of three groups, a stage-based intervention group (n = 175) that received different weekly email messages specific to their current stage, an action-message group (n = 175) that received a different “one-size fits all” weekly message tailored for action takers and maintainers, and a control group (n = 175) that received weekly email messages regarding nutrition. From baseline, 402 subjects completed a follow-up questionnaire. Three different questionnaires assessed changes in activity; a 7-day physical activity recall (PA), occupational activity (OA), and leisure activity (LA). ANOVA indicated no differences between baseline scores in the three activity groups for any of the outcome variables (PA:F = 1.28, p = .28; OA:F = 1.18, p = .16; LA:F = .03, p = .97). Within group analysis indicated the action-message group demonstrated a 3.8% increase in PA (2756 kcals vs 2861 kcals), a 8.4% increase in OA (8.46 vs 9.17), and a 8.6% increase in LA (6.48 vs 7.04). All increases were different from baseline (p = .05). The staged group also showed a significant (p = .05) increase from baseline (6.80 vs 7.23). In a separate group-by-movement Chi-square, no significant differences were seen between the control, stage-based, or action-message groups (X2 =.83, p = .93), however, three-times as many moved toward maintenance as moved away from maintenance. The Transtheoretical Model with its stages of change sub-component, is one of the most promising and popular models of behavior change. This study indicated that exercise interventions involving stage-based messages may be less effective than action-oriented messages. Future research of other online interventions will likely be needed to more fully understand the utility of internet-based intervention strategies.