Each session will last approximately 15 minutes, with five physiotherapy sessions taking place over a period of 2 months. The Self-Myofascial release protocol for the lower limbs using a Foam Roller and and Solid Ball Massage, adapted to patients with hemophilic ankle arthropathy will include: Self-Myofascial release of the plantar region using and Solid Ball Massage; Release of the myofascial components of the back of the leg using a Foam Roller; Release of the myofascial components of the anterior part of the leg using a Foam Roller; Release of myofascial components of the hamstring region using a Foam Roller; Release of the myofascial components of the adductor muscles using a Solid Ball Massage in a sitting position; Release of the myofascial components of the abductor muscles using a Foam Roller in lateral decubitus; Release of the myofascial components of the pelvitrochanterian muscles using a Foam Roller in a sitting position.

The subjects included in the control group will not receive Physiotherapy sessions and will continue with their usual routine of activity and physical exercise, and with the same drug treatment schedule with FVIII / FIX and analgesic drugs.

This study followed the protocol designed for patients with hemophilic knee arthropathy. For its implementation, a 30-cm long15-cm diameter foam roller was used, and a ball 22 cm in length and 8 cm in diameter. The total duration of the intervention was 15 minutes, with 7 sessions per week over a period of 8 weeks. The physiotherapist who supervised the intervention followed up on all patients by telephone on a weekly basis to check for the absence of haemarthrosis during the intervention and to detect the possible need for protocol adaptations depending on the clinical situation of each patient. Each patient was individually provided with instructions as to how perform the exercises during the pretreatment evaluation, customizing the program if necessary. All patients had access to a mobile application, designed ad hoc for the research study (He-Foam®), where they could learn about the exercises through demonstration videos.

Visual analogic scale (VAS). This scale will be used to evaluate the perception of joint pain, where knee joint pain ranges from 0 to 10 points (no pain to maximum perceived pain).

Pressure algometer. Measuring instrument used to evaluate pressure joint pain. The instrument shall consist of a measuring device attached to a hard rubber tip 1.1 cm in diameter. Its sphere shall be calibrated in kg/cm2 with divisions of 0.1 kg/cm2. The pressure algometry methodology applied was based mainly on the study by Hogeweg. Before taking the measurements, patients will be instructed to say "yes" as soon as pressure exerted by the algometer becomes slightly unpleasant. The pressure algometer shall be kept perpendicular to the surface of the skin with the right hand, stabilizing the axis of the instrument using the thumb and index finger of the left hand. The pressure shall be increased at a uniform rate of approximately 1 kg/cm2 per second. As soon as the subject, according to the instructions, says "yes", the pressure will be stopped and the score will be noted.