eMOTION: Examining Affective Mechanisms in Physical Activity Engagement

BEHAVIORAL

Physical Activity Goals mHealth Intervention

On days participants plan to exercise, they engage in two daily goal sessions (morning and evening). Morning sessions provide an activity goal for the day and ask the participant to create a plan, anticipate barriers, and brainstorm solutions for achieving this goal. The affect-based goal condition asks participants to engage in either (1) a type (50% of daily goals) or (2) a context (50% of daily goals) of physical activity that allows them to experience positive affect. Goals focused on context are randomly generated to suggest that the participant performs activity (1) in a place; (2) in a social situation; or (3) while listening to something that makes them feel good. The intensity-based goal condition asks participants to maintain a certain target heart rate range during physical activity. Starting heart rate reflects the approximate age-adjusted heart rate max, with goals progressively increasing from 55% to 70% heart rate max.

BEHAVIORAL

TYPE/CONTEXT enhancement

TYPE/CONTEXT augments intervention effects by providing tailored recommendations for activity types and contexts that satisfy personally-important psychological needs as rated by each participant at baseline. Ratings from a crowdsourced panel of adults on Amazon Mechanical Turk will be used to determine the potential for specific activity types and contexts to satisfy psychological needs; our tailoring algorithm will then recommend the corresponding activity type or context while accounting for reported constraints (e.g., ability, access). These details will be incorporated into a tailored recommendation provided to participants each Sunday as they make activity plans for the upcoming week. Specifically, the program will randomly select either type or context (i.e., location, audio, social) recommendations and will rotate every two weeks. For TYPE, participants' top 3 activity types are recommended; for CONTEXT, participants' top 3 activity contexts are recommended.

BEHAVIORAL

SAVOR enhancement

SAVOR implements a brief savoring exercise on the smartphone that takes place either after the planned physical activity session or during the evening goal session (after the self-monitoring module). Participants will respond to questions that are intended to enhance and prolong positive experiences during physical activity. To trigger attentional deployment, a common savoring strategy that involves intensifying experiences by focusing on them, participants will answer three open-ended prompts. These prompts are drawn from a prompt pool with slightly varied wording to promote a sense of novelty. Savoring prompts will rotate daily and have a day lag built in every week (i.e., Week 1 Monday Savoring Prompts are Week 2 Tuesday Savoring Prompts).

Physical Activity: Step Count

Time frame: Daily total for weeks 1-19

Daily steps will be calculated from minute-level accelerometer data. Fitbit Versa 3 smartwatches with internal accelerometers are worn for the duration of the study period, except while bathing or charging. Only days with sufficient wear time (defined as ≥ 10-hours of valid data, where no more than 20-minutes per hour has a consecutive step count of zero) are used for analysis.

Physical Activity: Minutes

Time frame: Daily total for weeks 1-19

Daily minutes of light, moderate, and vigorous physical activity will be calculated from minute-level accelerometer data. Fitbit Versa 3 smartwatches with internal accelerometers are worn for the duration of the study period, except while bathing or charging. Only days with sufficient wear time (defined as ≥ 10-hours of valid data, where no more than 20-minutes per hour has a consecutive step count of zero) are used for analysis.

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.