Predicted percentage of overall range-of-motion (ROM) limitation by age and severity, for 2- to 19-year-old males with hemophilia. Graph was created using separate regression models for severe, moderate, and mild hemophilia (models are presented in Table 2). Percentage of ROM limitation was calculated by setting categoric variables equal to the reference value and by using the severity group mean value for continuous variables such as body mass index and number of bleeds.