Review and special articleWebsite-Delivered Physical Activity Interventions: A Review of the Literature
Introduction
Regular physical activity decreases the risk of developing cardiovascular disease, diabetes, some cancers, obesity, osteoporosis, and other chronic conditions.1 Public health guidelines for adults recommend participating in at least 30 minutes of moderate-intensity physical activity on 5 or more days of the week.2 However, the proportion of the adult population meeting these guidelines is less than 50% in many industrialized countries.1, 3, 4, 5, 6 Thus, finding effective population-based intervention strategies to promote physical activity is a key challenge.
The Internet holds promise for wide-scale promotion of physical activity behavior change. Website-delivered interventions have a potentially broad population reach with availability 24 hours per day and widespread accessibility,7, 8 they have the potential to be hosted and promoted through state health agencies and nongovernmental organizations,7 and they are potentially cost-effective.8 In many industrialized countries, Internet access is greater than 50% and is increasing.9 Internet users are becoming more representative of the overall population, with users including more women, older adults, and people with low levels of educational attainment.10, 11 The Internet is identified as an important source of health information by more than half of its users, and may thus be an appropriate delivery medium for health behavior change interventions.12
Website-delivered physical activity interventions have the potential to overcome many of the barriers associated with traditional face-to-face exercise counseling or group-based physical activity programs. An Internet user can seek advice at any time, any place, and often at a lower cost compared with other delivery modalities.13 Although there may be many advantages of using the Internet for delivering health behavior change programs, to reach their public health potential, website-delivered physical activity interventions must first demonstrate feasibility and efficacy through rigorous scientific testing.
In 2000, the American Journal of Preventive Medicine published a set of articles that identified the potential of interactive health communications, including Internet and website-delivered interventions, for improving health behaviors.14, 15, 16, 17 At that time, there was little empirical literature to support these optimistic predictions. Since then, a wide range of studies evaluating website-delivered health behavior interventions have been reported. Several reviews have examined Internet or website-delivered health behavior change interventions;13, 18, 19, 20, 21 however, none have specifically focused on physical activity. A systematic review of study outcomes for website-delivered physical activity interventions is thus timely.
Three questions will be addressed: (1) What is the efficacy of website-delivered physical activity interventions? (2) Are there specific intervention elements that influence efficacy? (3) How well are participants engaged and retained? Answers to these questions inform an evaluation of the state of the evidence and are used to formulate guidelines and recommendations for future research.
Section snippets
Methods
The study protocol was adapted from previously published reviews22, 23, 24 and based on guidelines from the Cochrane Reviewers’ Handbook.25 The articles were independently reviewed and abstracted. Disagreements were discussed among the co-authors until consensus was reached.
Study Selection
The initial search across the four databases yielded 512 publications. Based on title and abstract, reviewing duplicates and irrelevant publications were eliminated, resulting in 77 studies. Reference lists of these publications yielded another 13 publications, in addition to seven publications that were already in the hands of the authors and two in-press publications that were provided by colleagues. After reviewing these 99 publications, 84 were excluded, as they did not meet one or more of
Discussion
This systematic review found modest evidence for the efficacy of website-delivered physical activity interventions, with a little over half of the studies reporting significant positive behavioral changes. However, the effect sizes for studies that found positive outcomes were small, and the intervention effects were mostly short lived. There was a clear decrease in efficacy when time to follow-up increased, with studies that had longer follow-ups being associated with less positive outcomes.
Conclusion
Research on website-delivered physical activity interventions is still at an early stage of development, and although progress has been made, and several studies show promising results, much remains to be learned about optimizing and enhancing these interventions to increase their efficacy. Intervening to influence physical activity over the Internet does not appear to be as straightforward as earlier optimistic predictions had suggested. However, this review suggests that the Internet still
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