The specific aims of the proposed study are:

• 1. To determine if web-based Motivational Interviewing (MI) is effective, compared to an informational web-based comparison group, in enhancing physical activity (PA) participation; and
• 2. To assess the mechanisms by which web-based MI enhances PA through changes in targeted cognitive mediators.

The specific hypotheses of the study include that:

• Hypothesis 1: Web-based MI will increase PA;
• Hypothesis 2: Web-based MI will lead to stage progression in the direction of increased readiness to participate in PA;
• Hypothesis 3: Web-based MI will influence theoretically identified cognitive variables;
• Hypothesis 4: Cognitive variables will mediate increases in PA participation.

Increasing physical activity (PA) is a public health priority. There is preliminary support for application of Motivational Interviewing (MI) for physical activity (PA), web-applications for PA promotion, web-based MI for behavior change, and finally web-based MI for PA. Based on collective findings in these areas of inquiry, it is necessary to investigate the efficacy of MI as a method that lends readily to practical applications for PA promotion. The current study seeks to investigate whether web-based MI can be applied in an adult population to enhance PA participation using a physician referral scheme. Additionally, mechanisms of behavior change are considered in order to inform future research and intervention.

Inclusion Criteria:

• Adults referred through primary care due to insufficient physical activity standards based on Centers for Disease Control (CDC) guidelines for aerobic activity.
• Must have internet access and e-mail.
• Cleared by physician for physical activity participation.

Exclusion Criteria:

• Greater than 10,000 steps per day on average based on baseline pedometer screening over the course of 7 days.