Down Syndrome (DS), a genetic condition marked by the presence of an extra chromosome 21, is associated with various cognitive and physical challenges. Children with DS often experience motor development issues, including reduced endurance and decreased trunk stability, which underscores the need for targeted interventions. Common impairments in individuals with DS include hypotonia, ligament laxity, reduced muscle strength, limited muscle co-contraction, poor postural control, and impaired proprioception. This study is driven by a lack of research on the effects of High-Intensity Interval Training (HIIT) in this population, despite its documented benefits in enhancing cardiovascular fitness across other groups. Existing literature supports the benefits of exercise interventions for people with DS, but the application and advantages of HIIT-particularly concerning endurance and trunk stability-are underexplored.