This group will not take any exercise intervention.

This group will get traditional therapy that is include range of motion exercises and resistance exercise training.

This group will get a specific programme that combinated with closed kinetic chain exercises and core exercises training

The therapy program will planned for 12 weeks and the sessions will be performed in 45 minutes (min) for 2 days a week. The lower extremity range of motion exercise and strengthening exercises will be applied on the mat 10 repetition. The number of repetitions and type of exercises will be changed every 3 weeks.

Mc Gill Short Form will used to determine the type and severity of the pain. A short form of the McGill Pain Questionnaire (SF-MPQ) has been developed. The main component of the SF-MPQ consists of 15 descriptors (11 sensory; 4 affective) which are rated on an intensity scale as 0 = none, 1 = mild, 2 = moderate or 3 = severe.

Time Up and Go test will used to determine ambulatory mobility. Time up and go test required documenting the time in seconds that subjects required to: "rise from a standard arm chair, walk to a line on the floor 3 meters away, turn, return, and sit down again." If relapsed time score is increased, that is mean mobility function will worse.

Two minutes walk test will used to determine physical activity. 2-minute walk test (2MWT) is classified to represent the most suitable method to assess the submaximal level of functional exercise capacity in children. This test measures the distance that a patient or participant quickly walk on a flat, hard surface in a period of 2 minutes.If the covered distance is increased, that is mean functional capacity will worse.

Sit to stand test will used to determine physical activity. The sit-to-stand test measures time needed to complete three consecutive sit-to-stand cycles as quickly as possible. The higher the rate of three-repetition sit-to-stand (repetitions per second), the more strength a children has.

The Children's Quality of Life Scale ( PedsQL) will used to determine to quality of life level. The quality of life scale for children questions the last month of children and adolescents. It is a 5-point Likert-type scale with never 100 points, rarely 75 points, sometimes 50 points, often 25 points and always 0 points. The total score is obtained by dividing the scores obtained from the scale by the number of filled items. The higher the total score, the better the quality of life.

Electro goniometer measurement will used to determine knee proprioception

Hemophilia Joint Health Scale will used to determine bilaterally knee, elbow and ankle joint health. Total score of the scale is 124 point. The higher score of the scale, the more deficit joints have.