Table 1.

Overview of the persuasive strategies of the PAUL app, the app modules and a short description of the module.

Persuasive strategy	App module	Short description of the module
Reminders	Reminder module	• Timing of the reminders is adaptively personalized based on calendar availability, weather, the time of the day/day of the week, and previous PA behavior with the PAUL app. • Textual push notifications with a short and varying content.
Goal setting	Goal-setting module	• Each user sets a personal long-term PA goal for number of PA sessions/week and the duration of the PA sessions. • The system defines the (weekly and daily) short-term goals for the user based on the self-reported fitness level • The goals gradually increase in difficulty in order to reach the long-term goal by increasing PA time with ~10%. • Option to view and change the goal at all times.
Monitoring of behavior	Self-monitoring module of strength exercises	• After receiving a strength exercise prompt, the user has to log if she performed the exercise.
	Self-monitoring of outcome of behavior	• The user has the option to report notes about the training session, training intensity, and how satisfied she was with the training session.
	Automatic tracking module	• The app records and stores PA metrics during the app use (frequency, duration, speed, and distance). The user has to press “start” to initiate the behavior tracking. • The app also records and stores situational characteristics during each session and when sending a reminder (weather type, calendar availability, time, and date)
Feedback on behavior	Sustained feedback module	• The user can view simple on-screen feedback during PA and receives simple audio feedback.
	Cumulative feedback module	• The user can view a PA report immediately after the PA session with simple metrics such as distance and time (numerical). • The user can view a history consisting of all PA reports (including a map of the running route). • The user can view her progress toward weekly goal (home screen and goal-setting tag).
Rewards	Praise module	• Praise message after attaining the goal in on the landing page
Instructions	Instruction video module	• Instruction video to perform strength exercises (pushups and squats). • Triggered by a beacon during app usage. The user receives an audio tune and pop-up.