This study evaluated the efficacy of a 12-week Internet intervention to help sedentary older adults adopt and maintain an exercise regimen. A total of 368 men and women over 55 years of age (x = 60.3; SD 4.9 ) were recruited and screened on line. They randomized into treatment and control groups and assessed at pre-test, 12 weeks, and at six months.

The multivariate model was significant at posttest (p = .001; large effect size) and at six months (p = .001; medium effect size). At posttest, intervention participation showed significant improvement on 13 of 14 outcome measures compared to the control group. At six months, treatment group participants were found to maintain large gains compared to the Ctrl participants on all 14 measures.

Based on the treatment group users self reported fitness level, activity goals, and self-identified barriers to exercise, the program helped users select exercise activities in the areas of endurance, flexibility, strengthening, and balance enhancement. They returned weekly for automated video and text support and education, with the option to change or increase in their exercise plan, and on-going problem solving to overcome barriers to exercise.

Inclusion Criteria:

• > 54 years of age;
• < 61 minutes of exercise per week;
• internet connection; email address

Exclusion Criteria:

• too young;
• too active;
• no web access;
• no email