PROJECT SUMMARY AND ABSTRACT: Chronic musculoskeletal pain (CMSKP) is common in adolescents. Participation in regular physical activity (PA) is effective in reducing CMSKP but PA participation is still below recommended levels. There is a need to better understand ways to better promote PA in adolescent CMSKP (e.g., decreasing sedentary activity vs. increasing moderate to vigorous PA), factors that affect PA (e.g., resilience, pain modulation, stress dysregulation), and the mechanistic underpinnings of how these factors affect PA and pain. This knowledge may lead to the development of improved interventions for CMSKP. Psychological resilience factors that build on positive attributes, such as self-efficacy, motivation, and psychological flexibility may help adolescents to engage in PA. While resilience factors are important for overall pain coping, they only recently are being considered as predictors for PA. The overall goal of this proposal is to develop and pilot a feasibility study of an intervention that increases resilience for PA in adolescents with CMSKP. This is significant because the development of such an intervention may lead to improved PA and subsequently improved chronic pain for adolescents with CMSKP. This study first evaluates pathways of resilience factors on PA and pain in adolescents with CMSKP (Aim 1), and the modulation of pain and stress. 60 adolescents with CMSKP will complete self-report measures of resilience and vulnerability factors, and objectively measured PA, pain (Quantitative Sensory Testing), and stress (Cortisol Awaking Response). We will evaluate whether endogenous pain modulation and stress regulation mediate the relationships between resilience and PA. This study also will consider resilience factors that are significant in predicting less sedentary PA as intervention targets, and it will develop, refine (Aim 2) and (Aim 3) conduct a pilot feasibility and acceptability study of a resilience-focused chronic pain intervention for youth (Pain REsilience Promotion for Youth [PREP-Y]). The manual will be developed based on an established treatment program for adolescent CMSKP in adolescents (i.e., FIT Teens) and modified to target resilience mechanisms and sedentary activity. This will be done with integrated feedback from content experts in pediatric pain and CMSKP patients. The intervention will then be provided to 30 patients in groups of 4 to 6. This project will be implemented as part of a strong career development plan consisting coursework, experiential training, and intensive mentorship from a team of experts in pediatric behavioral intervention development and evaluation, psychological factors of pediatric pain, physical activity intervention, and pain physiology and assessment. Completion of this study will occur across two academic medical centers with a joint department of pediatrics, a well-establish pain treatment service, and research institutes to promote the growth and development of research fa...