Both training and use of scripts helps to ensure fidelity of the intervention. Fidelity will be assessed using basic metrics such as number of sessions completed, any deviations from the intended weekly schedule and the length of each session. Fidelity is also assessed using the detailed notes that the intervention coaches complete after every intervention session. Two primary components in each intervention coaching session that are expected to be present are (1) discussion of the tenet of SCT addressed in each session and (2) discussion and exploration of activity monitor (Fitbit results) and adjustment of goals as needed. Intervention notes will be reviewed and primary intervention components present will be recorded. This process will be completed by a research team member who is not involved with the intervention (ie, not an intervention coach), and the principal investigator (PM). The percentage of participants that receive at least 80% of the primary intervention components throughout the intervention will be reported. In addition, a total of 8–10 intervention sessions will be audio recorded and transcribed. The main purpose of the recordings is to allow spot checking for intervention components. The recordings are also used as a teaching tool during the intervention, which helps to ensure that interventionists use similar approaches. Finally, use of the Fitbit is an important part of the intervention. Its use will be tracked by one research assistant using Fitabase. Intervention coaches also track the participant’s use of the Fitbit wearing via the Fitbit website. Participants will be reminded to wear the Fitbit if it is apparent they are not wearing it (ie, no steps).