The present study aims to evaluate the modification of functional capacity induced by an adapted physical activity program in subjects with haemophilia. The exercise program used aims to improve joint mobility, muscle strength, static and dynamic balance, motor coordination. The program is structured in 1 hour sessions of 2 days/week and lasts 6 months. The primary endpoint is the change in functional capacity calculated as the difference between the baseline assessment and the 3 and 6 month assessment of the 6 Minutes Walking Test measured with the G-Walk (BTS Bioengineering S.p.A).