Background/Objectives: Physical inactivity and sedentary lifestyles remain leading behavioral risk factors for chronic disease across generations. Mothers with young children face unique barriers to exercise, including time constraints, fatigue, and limited access to supportive environments. Lion Hearts was developed to address these barriers through a family-centered, community-based approach that integrates physical activity, strength training, and health education. This protocol describes the systematic application of the Intervention Mapping (IM) framework to develop Lion Hearts, a multigenerational CrossFit-based program for mothers and children. Methods: Following the first four steps of the IM framework—needs assessment, matrices, intervention design, and program creation—behavioral determinants were identified through literature review, national data, and community input. The resulting 12-week program integrates twice-weekly family CrossFit sessions, monthly cardiovascular health workshops, and weekly home-based challenges delivered through local affiliates using a train-the-trainer model. Results: IM produced a theoretically grounded and evidence-based intervention targeting individual (self-efficacy, outcome expectations), interpersonal (modeling, relatedness), and environmental (access, social support) determinants. The process resulted in detailed logic models, behavior change matrices, and implementation materials, including family handbooks and coach guides. Conclusions:Lion Hearts represents a scalable, multigenerational approach to CVD prevention that leverages existing community fitness infrastructure. By embedding prevention within family systems and CrossFit affiliates, the program offers a sustainable, replicable model to enhance physical activity, strengthen family health behaviors, and reduce intergenerational CVD risk.

Children and adolescents with disabilities experience disproportionate challenges in achieving recommended levels of physical activity (PA) and adequate sleep, two core determinants of health and functional well-being. This systematic review examined associations between meeting PA guidelines and sleep duration among youth with disabilities. Following PRISMA guidelines, MEDLINE, PsycARTICLES, and SPORTDiscus were searched through Spring 2024 for studies assessing PA and sleep in children and adolescents (<18 years) with disabilities using subjective or objective measures. Data were extracted from 28 studies (N = 138,016) and synthesized using qualitative methods and regression-based quantitative analyses to examine the effects of diagnosis category and PA guideline adherence on sleep duration. The diagnosis type was associated with sleep duration, with youth with autism spectrum disorder (ASD) exhibiting shorter sleep than those with physical disabilities. Meeting PA guidelines (≥60 min/day) was associated with longer sleep duration among youth with ASD, but not consistently across other diagnostic groups. Qualitative findings further indicated diagnosis-specific variability, with PA positively associated with sleep outcomes in ASD, attention deficit/hyperactivity disorder, and epilepsy, and mixed associations observed for cerebral palsy and intellectual disability. These findings suggest that PA may support sleep health in specific disability groups. Given persistently low PA participation among youth with disabilities, integrating accessible, diagnosis-specific PA opportunities within school, community, and clinical settings may represent a feasible strategy to improve sleep and overall health.