Children with Down Syndrome have joint laxity, low muscle tone, and cognition impairments that lead to delayed walking and exploration compared to their typically developing peers. Supporting mobility at a developmentally appropriate age can benefit not only physical development, but also social, emotional, and cognitive development. There are a wide range of mobility aids that children with other disabilities use, like gait trainers and powered mobility – but evidence is lacking to support their use in prewalking children with Down Syndrome. The proposed project will test the ability of two mobility aids, partial bodyweight support and powered mobility, to promote increased mobility and play in young children with Down Syndrome. This TL1 application will fund the training of Ms. Hoffman, a PhD Student in the Department of Mechanical Engineering, whose research is at the intersection of accessibility, biomechanics, and rehabilitation medicine. In parallel, we aim to 1) measure exploratory behaviors during play with both devices, 2) measure a child's postural alignment and muscle activity with both devices, and 3) conduct a stakeholder analysis using qualitative interviews and children's responses. Twelve participants with Down Syndrome, from 12 to 36 months of age, will join four play sessions: a) control – no devices, b) partial bodyweight support, c) powered mobility in a sitting posture, d) powered mobility in a standing posture. We will quantify the impact of device use on environmental exploration of the play space via overhead cameras. Additionally, we will use electromyography (EMG) to measure muscle activation and wearables sensors (IMUs) to measure posture with and without mobility devices. Finally, we will conduct qualitative interviews to understand caregivers' and clinicians' perspectives on using mobility devices to augment play and exploration. Ms. Hoffman aspires to lead an independent research group specializing in the evaluation of mobility and play technologies for young children with disabilities. Her project is poised to expand her engineering training with co-sponsor Dr. Kat Steele to create a diverse range of sensing metrics that cater to participants' unique needs, ensuring comfort and durability. Ms. Hoffman will also collaborate with clinicians, forming a strong foundation for her future translational research. Didactic coursework and guidance from co-sponsor Dr. Heather Feldner will allow Ms. Hoffman to build her qualitative research skills to incorporate the perspectives of all stakeholders into her research and enrich her technical background. This award will not only support completion of her PhD but will foster her growth as an independent researcher through her multidisciplinary mentorship team and focused career development plan. In sum, Ms. Hoffman's participation in the TL1 program through the INCLUDE initiative is poised to equip her with essential skills to drive the future translation and advancement of pediat...