Hemophilia is an inherited bleeding disorder characterized by recurrent musculoskeletal bleeding, particularly into joints, leading to impaired physical function and reduced functional performance. The 30-Second Sit-to-Stand Test (30STS) is a simple, reliable, and valid measure of lower extremity functional performance; however, evidence regarding its performance in individuals with hemophilia remains limited. This cross-sectional observational study aims to compare 30STS performance between adults with hemophilia and age-matched healthy controls and to investigate the relationship between 30STS performance, joint health, and activity level in individuals with hemophilia. Fifty-eight participants (29 individuals with hemophilia and 29 healthy controls) aged 18-35 years will be recruited. Participants will complete the 30STS. Individuals with hemophilia will additionally undergo joint health assessment using the Hemophilia Joint Health Score (HJHS) and activity evaluation using the Hemophilia Activities List (HAL).