Development of a Mobile Health Snacktivity^TM App to Promote Physical Activity in Inactive Adults (SnackApp): Intervention Mapping and User Testing Study (Preprint)

Background Despite the unequivocal evidence demonstrating the benefits of being physically active, few people manage to meet the recommended guidelines for physical activity (e.g. 150 minutes of moderate to vigorous physical activity. There is no reason to suggest that this will change without the development and implementation of innovative interventions. The use of mobile health technologies have been suggested as a mechanism to employ innovative health behaviour change intervention. Therefore, this paper reports the systematic, theory-driven processes and user testing applied to develop a smartphone-based physical activity application (SnackApp) to promote participation in a novel physical activity intervention. Methods and Results Intervention mapping was used to develop the SnackApp via a six step process. These steps include a needs assessment and identifying the determinants and behaviour change techniques. The SnackApp was developed based on control theory and habit formation theory. The SnackApp was developed to be linked to a physical activity tracker (Fitbit Versa Lite) for automated capture of physical activity and includes the provision for goal setting, activity planning, social support as well as the delivery of health and behaviour change information. As part of the intervention mapping process, the SnackApp was user tested for 28 days in 15 inactive adults. App engagement (as measured by mobile app analytics) was analysed to determine app use and inform further SnackApp development. Over the 28-day study period participants engaged with the SnackApp on average 77 times, for an average total SnackApp time use of 12.6 minutes per week, with most of this time spent on the SnackApp dashboard (14 bouts lasting 7.5 minutes per week). On average, engagement with the SnackApp was higher among males than females when considering overall use. App rating score as measured by user mobile application rating scale, was 3.5/5 suggesting the SnackApp was rated as moderate to good on the rating scale. Conclusion This article illustrates the development of an innovative mobile health app using a systematic theory-driven framework. The approach can guide the development of future mobile health programs. User testing of the SnackApp suggests that physically inactive adults will engage with the SnackApp, indicating its applicability of use in physical activity interventions.