Web-based exercise motivation program helps couch potatoes to get moving as well as traditional, print-based programs, a new study suggests.

In Monday's issue of the Archives of Internal Medicine, researchers in the U.S. compared tailored direct mail programs aimed at changing sedentary behaviour to standard and tailored internet approaches.

Nearly 250 healthy, sedentary adults with an average age of 45 were randomly assigned to one of the three groups.

Those in the tailored internet group were asked to log on to a website designed by the researchers that included educational materials, tips for adopting and maintaining physical activity, and goal-setting functions.

They were also e-mailed monthly questionnaires and received immediate feedback to their responses.

The tailored print group received the same information but the material and feedback was sent in the mail.

The standard internet group received links to physical activity web sites that are widely available and were not customized by the researchers. This group also filled in logs and questionnaires but they received no feedback.

Public health benefits

After six months, those in the tailored internet group reported about 120 minutes of physical activity per week, compared with 112.5 minutes in the tailored print group and 90 minutes among standard internet participants.

After 12 months, participants reported 90, 90 and 80 minutes of physical activity per week respectively.

"Because the largest public health benefit in physical activity interventions comes from having populations of sedentary persons become more active rather than already active persons becoming more active, the interventions, if widely implemented, could create substantial public health benefits," the study's lead author, Bess Marcus, a professor of psychiatry and human behaviour at Brown University's medical school in Providence, R.I., said in a release.

The findings are important, Marcus said, because they provide evidence that different ways of delivering motivation are equally effective and may help overcome barriers such as lack of access to fitness facilities and time constraints

Walking was the most common activity reported. Overall, participants showed a 5.2 per cent improvement in fitness after six months, and 5.9 per cent after 12 months.

Previous studies suggested directed mail programs might help change behaviour, but the lack of immediate feedback, interactivity and postage are drawbacks.