A Fitbit One is worn throughout the intervention as a self-monitoring tool, starting after baseline ActivPAL3 removal (ie, 1 week after baseline assessment). Participants retain the Fitbit after intervention completion. Self-monitoring occurs slightly differently in the Sit-Less versus the Move-More stage, as described below. The Fitbit One does not provide real-time information about sitting interruptions to the participants, but alarms can be set as a reminder to stand up throughout the day. For review of sedentary time during the Sit-Less stage, participants are instructed to login to the Fitbit website daily to view their daily activity log graphs. The logs show daily activity across time and sedentary periods are displayed with no steps. Participants are taught to use the logs so they can recognise sedentary and active periods, with example graphs provided in the programme manual to assist interpretation. By contrast, in the Move-More stage participants receive real time information about step counts on their phone. During the weekly coaching sessions in both stages, the participants and coaches view and discuss the activity logs together as they provide information about both sedentary time and stepping.