Project Summary/Abstract. Although previous research has identified the importance of a human-centered design approach to the development of digital behavior change interventions (DBCIs) which considers the digital literacy and health status of the target population, current commercially available mHealth applications do not meet the language, prerequisite knowledge, incentive, and unique cultural needs of Hispanic/Latinos3-7. Furthermore, simply taking the protocol of English language, higher digital literacy DBCIs, and translating the material to match the user’s preferred language has not been found to positively influence DBCI app usage or engagment7. The parent R01 is being conducted in Greater San Diego, where the population is estimated to be 34% Hispanic/Latino, and targets enrollment to recruit a representative sample of this region16. Therefore, the parent grant provides an excellent opportunity to study the implementation of, and engagement with, a PA focused DBCI among a diverse sample population including a significant group of Hispanic/Latino participants. This study will use a multimethod approach (qualitative and quantitative) to provide an in-depth understanding of the unique factors related to DBCI engagement among Hispanic/Latinos. These results will directly inform the design and optimization of the next generation of culturally relevant and engaging DBCIs based on the control optimization trial (COT) approach to developing personalized and perpetually adapting interventions. This diversity supplement will support Mr. De La Torre in developing a culturally adapted version of the YourMove intervention, specific for Hispanic/Latino families. This target produces multiple synergistic benefits including: 1) for Mr. De La Torre, the proposed work would be excellent for enabling him to apply for a possible K-award from the NIH, to support his transition into becoming a faculty member committed to developing DBCIs that specifically serve Hispanic/Latino populations in his career and to advance health equity, 2) for Hispanic/Latino communities, the diversity supplement will enable the rigorous cultural tailoring, through the supplements aims, and 3) for the parent R01, this diversity supplement will enable the methods and approaches to be used and refined, with a specific focus on reducing health inequities and disparities; thus, the diversity supplement provides a mechanism for the parent R01 to contribute more meaningfully to advancing health equity, by providing a concrete, actionable pathway for developing a translated and culturally appropriate extension of the YourMove intervention. The activities proposed in this supplement remain within the original scope of the parent award and will increase the impact of the knowledge gained from the parent study, particularly for Hispanic/Latino study participants.