The effectiveness of distance interventions for increasing physical activity: a review.

OBJECTIVE Evaluate the effectiveness of distance physical activity interventions to establish intervention features that are key to success. DATA SOURCE Computerized searches for randomized controlled trials (RCTs) of distance physical activity interventions and visual scans of reference lists were performed between March 2004 and July 2006. STUDY INCLUSION AND EXCLUSION CRITERIA Studies were included if they (1) employed a randomized controlled design, (2) encouraged physical activity in adults, and (3) had no face-to-face contact between participants and researchers or health educators. DATA EXTRACTION Twenty-two studies were found that met the inclusion criteria. Authors assessed the quality of the studies and coded articles according to key intervention features. DATA SYNTHESIS This review is a systematic narrative review. Heterogeneity and poor study quality made formal meta-analysis inappropriate. Nevertheless, effect sizes were calculated for studies comparing intervention with control. RESULTS Overall, distance interventions increased physical activity in the short term (between-group effect size range, -.2 to .45). Print medium plus telephone contact was the most effective delivery mode. CONCLUSIONS Poor study quality prevented firm conclusions. However, distance interventions were found to promote physical activity in the short term for some populations. This review provided limited support for the efficacy of distance exercise interventions and revealed limitations of the extant literature. Expansion of RCT research into distance approaches to promoting physical activity is warranted.