Internet-based randomized study on the effectiveness of the physical activity program active-online.ch - a feasibility study
www.active-online.ch is a freely available Internet-based counselling and motivation program for health enhancing physical activity. It is based on the Transtheoretical model of behaviour change and is disseminated population wide with a multimedia strategy. The feasibility of an Internet-based, randomised design for a longitudinal study of its effectiveness was investigated. Self-selected participants were recruited for a "health study" using various media channels (print advertisements, Internet banners, e-mail), answered an online questionnaire (n=321), were randomised into an intervention (n=97) and a control group (n=74) and re-contacted by e-mail after six weeks and six months to answer an online follow-up questionnaire. 6% of the potential participants stopped when their e-mail address was demanded. E-mailing and a print advertisement were effective to recruit study participants. Response after six weeks was 76%, complete data of all three measurements are available from 63% of the participants. The participants who quit the online questionnaire prematurely were significantly more often women, married and reported better subjective health than individuals willing to participate. Non-respondents after six months were significantly more often women, smokers and less educated than respondents. 57.4% of the recruited participants were physically inactive. This corresponds to the proportion of inactive persons in the Swiss population.
