Table 1 Summary of the most recent studies using internet interventions to promote physical activity

First author	Sample size and population	Study design	Intervention design	Intervention duration	Major dependent variable(s)	Results	Unique features
Napolitano12	65 Worksite men and women; mean age 43 years	Internet vs control	Access to interactive website with weekly e-mail	3 Months; 1 and 3-month follow-up	Stage of change for PA; minutes of PA	Significant differences between groups for progression in stage of change and minutes of PA	One of the first internet-based PA studies
Rovniak13	61 Women; mean age 40 years	General feedback vs tailored feedback	Introductory walking session; 2 e-mails/week	12 Weeks; 3-week and 1-year follow-up	1-Mile walk; minutes walking/2 weeks	Significant improvement in 1-mile walk in tailored feedback; no other significant differences between groups	1-Year follow-up
Woolf14	256 Men and women; aged 18–60 years	Interactive tailored vs static website	Physician referral to interactive or static website	1 and 4-month follow-up after initial log on to website	Multiple measures of PA, diet, alcohol use, smoking	Significant increase in light/moderate PA at 1 month; no other significant changes	Used physician referrals to website
Marcus15	239 Men and women; mean age 44 years	Tailored internet vs tailored print vs standard internet	Interactive stage-based website with e-mail prompts	12 Months, no follow-up	Minutes of PA; meeting national PA guidelines	Significant changes from baseline to 6 and 12 months in all three groups. No significant differences among groups at any time point	12-Month intervention
Spittaels16	526 Belgian men and women; mean age 40 years	Tailored PA advice with e-mail vs tailored PA advice vs non-tailored PA advice	One-time log on for tailored/standard advice; 5 e-mails delivered over 8 weeks	8 Weeks; 6-month follow-up	Minutes of PA; sitting time	Significant increase in all three groups. No significant differences among groups	First fully automated internet-based intervention
Carr17	N = 32; US male and female adults; mean age 35 years	Internet vs wait-list control	Weekly e-mail or phone contact with study facilitators for the first 2 weeks; then e-mail contact every other week until week 16	16 Weeks; assessments at baseline and 16 weeks	Steps/week; body mass index; total cholesterol/HDL and triglycerides; 1-mile walk test	Significant changes in steps/week and 1-mile walk test in both groups; significant differences between groups in waist circumference, total cholesterol/HDL, and triglycerides when controlling for age	Found significant changes in blood lipids
Franko18	N = 476; US college students from six universities nationwide; mean age 20 years	2 Sessions on website vs 2 sessions on website with a booster session vs 2 sessions on control website	Interactive website targeting nutrition and physical activity	6 Months; assessments at baseline, 2 weeks post-baseline, 3 and 6 months	Fruit/vegetable intake; readiness to change fruit/vegetable intake; nutrition knowledge; previous 7 day physical activity; social support/self-efficacy for dietary change; benefits/barriers for physical activity	Groups 1 and 2 significantly increased fruit and vegetable intake, motivation to change eating, social support and self-efficacy for dietary change and attitude towards exercise	Nationwide recruitment targeting college students

HDL, high-density lipoprotein; PA, physical activity.