Factorial Trial Testing Guided Thinking Tasks to Optimize a Physical Activity Intervention

Factorial Trial to Test Unique and Combined Effects of Guided Thinking Tasks to Optimize a Physical Activity Intervention Among Underactive Adults

The objective of this study is to optimize a novel, audio-recorded physical activity intervention that is scalable. Using principles of the Multiphase Optimization Strategy (MOST) framework, a full factorial study will test the unique and combined effects of different intervention components to identify which combination of components is optimal for increasing physical activity and mechanisms by which the components are or are not effective. This information will inform decisions about an optimal intervention package that is effective, efficient, and minimizes participant burden.

Eligible participants who provide informed consent will be enrolled in a 6-week study. At the baseline session, participants will be randomized to listen to a brief audio-recording of different guided thinking tasks. The audio-recordings are based on combinations of four different intervention components that will be tested in a 2 (positive affect imagery vs. neutral) x 2 (episodic future thinking vs. recent thinking) x 2 (action planning: yes, no) x 2 (dose: high vs. low) factorial trial. Participants will also complete a 30-minute brisk walking session on a treadmill. Participants will return for weekly visits in which they again listen to their assigned audio-recording and complete a 30-minute brisk walking session.

Inclusion Criteria:

• Adults ages 18-64
• Not currently meeting physical activity guidelines (<150 minutes/week of self-reported moderate-to-vigorous physical activity)
• Capable of providing informed consent
• Access to a smartphone with active data plan
• Willing to attend all study visits and comply with the protocol
• Conversant in English

Exclusion Criteria:

• BMI > 40
• orthopedic problems that would limit physical activity
• self-reported coronary artery disease, stroke, COPD, chronic bronchitis, emphysema, diabetes