Using a full factorial design , participants were randomized to @ of the @ levels of each experimental factor ( message tone -LSB- prescriptive vs. motivational -RSB- , navigation autonomy -LSB- dictated vs. not -RSB- , e-mail reminders -LSB- yes vs. no -RSB- , and receipt of personally tailored testimonials -LSB- yes vs. no -RSB- ) and provided access to the online intervention .