There is strong evidence that physical activity is effective in reducing the risk of chronic diseases such as cardiovascular disease, high blood pressure, and depression (Warburton et al., 2006). Despite this evidence, a majority of adults do not meet the minimal requirements for physical activity wherein health benefits are thought to occur (Cameron et al., 2007). Although there are many reasons why individuals lead primarily sedentary lives, part of the low level of physical activity in North America is likely related to the increased opportunities to be sedentary, including an increase in sedentary occupations (Biddle and Mutrie, 2001). Indeed, because many North American adults work in primarily sedentary jobs, two reports, the U.S. Surgeon General’s report on “Physical Activity and Health ”(1996) and Health Canada’s “Business Case for Active Living at Work ”(2001) make recommendations for physical activity initiatives in the workplace. Such initiatives are further warranted because while sedentary lifestyles have been linked to many chronic diseases, it has also been recognized that sedentary occupations are linked to worker’s compensation claims and increased absenteeism. For example, Musich et al., 2001 found that physical inactivity, smoking, and life dissatisfaction were controllable health risks that were highly related to workers’ compensation costs. Other researchers found that being overweight or obese and having high stress had the highest correlation with worker absenteeism and that initiating a wellness programme decreased absenteeism (Wright et al., 2002). In an economic analysis of risk factors and health-care expenditures that included data from over 46,000 employees, it was found that employees at high risk for seven modifiable risk factors, including sedentary lifestyle, incurred significantly higher health-care expenditures than those employees at low risk (Goetzel et al., 1998). Although it has been reported that over 80% of North American worksites with 50 or more employees have some level of health promotion programme (Riedel et al., 2001), typically only between 15% and 30% of eligible employees participate (Gebhardt and Crump, 1990). Further, many of the participants are already active (Sharratt and Cox, 1988). Identified challenges to successful worksite physical activity programmes include limited time for those employees with inflexible schedules, and potential embarrassment due to exercising around coworkers (Wong et al., 1998). Because of the flexibility and anonymity afforded, one possible avenue for overcoming such challenges is to offer interventions through the internet. Further, tailoring interventions to the Transtheoretical Model (TTM) stages of change (precontemplation, contemplation, preparation, action, and maintenance; Prochaska and Norcross, 1994), have shown to be effective with both web-based interventions (Napolitano et al., 2003; Marshall et al., 2003) and in more traditional forms of interventions such as print handouts (Marcus et al., 1998). For example, a website which included stage matched information resulted in increases in physical activity and motivation to be physically active (Napolitano et al., 2003). However, these authors found that the greatest change was from baseline to one month, and thereafter, there was little change. Qualitative data indicated that this was because the website content was not updated and, therefore, participants did not feel the need to return to the site after the first month. Other authors have reported that an 8-week web-based intervention tailored to stage of change decreased the amount of time spent sitting, but only a matched print-based intervention resulted in increased physical activity in those who were inactive at baseline (Marshall et al., 2003). While there are possible advantages to initiating a website intervention in a workplace, one being that employees are already familiar with the main employer website and can easily navigate to the intervention page (Shephard, 1996), it has been found that despite targeted e-mails, employees did not visit a worksite health promotion website very often and use declined rapidly over time (Leslie et al., 2004). Work site physical activity interventions based on the internet hold some promise for changing employee behavior. The most effective interventions are those that are stage matched to the individual. However, one of the major criticisms of this approach has been that information contained on the web page becomes stale over time and that employees no longer access the cite for this reason. More research is necessary to evaluate the effectiveness of stage-matched web-based physical activity interventions that continuously update the internet information, thereby making it more appealing to the employee for longer periods of time. When considering physical activity interventions, it is also important to consider self-efficacy which has been shown to serve as a mediator between interventions and behavior (Bandura, 1997). Exercise self-efficacy is the belief that an individual holds in his or her ability to manage and plan regular exercise sessions in their life and is a primary determinant of effective exercise adherence (Dawson et al., 2000). Exercise adherence is also affected by beliefs that one can exercise regularly in the face of numerous obstacles or barriers (barrier self-efficacy) (Dawson, et al, 2000). As such, building confidence to overcome barriers to walking and improving confidence to schedule and plan regular exercise sessions is paramount to educational and activity interventions. Self-efficacy has also been shown to increase with the stages of behavior change outlined by the TTM (Marshall and Biddle, 2001). One of the few longitudinal tests of the TTM with exercise suggested that self-efficacy was a good predictor of stage transition (Plotnikoff et al., 2001). An additional consideration for workplace health promotion and exercise research is the issue of self-selection. Due to the generally low participation rates in such programmes as outlined above, it is important to determine who may be interested in participating. Thus, although self-selection is often said to be a limitation of research, the converse may also be true. Self-selection of intervention type strengthens the external validity of the findings by more readily representing the actual volitional control that individuals hold with respect to their choice of intervention formats. Based on these considerations, the purpose of this research was to compare the efficacy of a group-based educational exercise intervention with an internet-based intervention in terms of positively influencing stage of behavior change and exercise and barrier self-efficacy. An additional purpose was to determine if a web-based intervention attracted different participants than those who enrolled for a group-based on-site intervention. Two important questions to be answered were a) Are employees more interested in on-line interactions than structured group meetings? and b) Are there differences between intervention participants in terms of readiness to change, demographics, and psychosocial characteristics such as self-efficacy? It was hypothesized that: 1) The internet-based intervention, rather than the group-based intervention, would attract individuals in earlier stages of behavior change because the internet-based intervention provides the option to maintain anonymity which is an important need for some employees, particularly those who are currently inactive; 2) the internet-based intervention would attract more participants than the group-based intervention because of the relative ease of access and flexibility it afforded (Napolitano et al., 2003); and 3) both interventions would lead to increased exercise and barrier self-efficacy. |