Fifty-six boys aged 10–14 years with moderate hemophilic knee arthropathy were randomized to receive Kinect-based virtual reality (KBVR) exercises plus conventional physical therapy (n=28) or conventional physical therapy alone (n=28). The primary outcomes were improvements in gait characteristics, including step length, cadence, walking velocity, peak knee extension moment during stance, and knee flexion amplitude during swing. Secondary outcomes included functional ability (6-minute walk test) and physical activity levels (Adolescents’ Physical Activity Questionnaire). Outcomes were assessed at baseline and after 12 weeks. Overall, the KBVR group demonstrated significant improvements in all primary and secondary outcomes compared to the control group, These findings suggest that KBVR is an effective supplement to physical therapy for enhancing mobility and physical activity in this population.