The core stability exercises will be used for core stabilization training of group (A) in addition to traditional physical therapy. The core stability program included 3 levels. Each exercise lasted 5 min, and the children shifted from one exercise to the next after the complete performance of the preceding exercise. The first (simple) level included supine abdominal draw-in (20 repetitions), abdominal draw-in with both knees to the chest (10-20 repetitions), and supine twist (10-20 repetitions). The second (medium) level included pelvic bridging (3e5 repetitions) and twist with a medicine ball (10e20 repetitions). Finally, the third (difficult) level included bridging with the head on a physio ball (the position was held for 3-5 s, followed by a slow relaxation phase, with 10-20 repetitions)

Rebound exercises will be applied for group B. this group will receive rebound exercise training in addition to traditional physical therapy . Rebound exercises were conducted on a mini-trampoline and BOSU ball. Passive bouncing will be conducted while the child was standing with his/her feet a shoulder-width apart. The therapist will held the child's legs while applying upward and downward movement. The bouncing started slowly. The child then will progress to include the rebound exercises, starting with active bounce, where in a hands free manner the therapist will ask the child to speed up or slow down the bounce rate according to the child's abilities

The treatment session lasted one hour with short breaks of around 10 minutes and will be conducted three times per week for twelve successive weeks

it measures the degree of tilting for each axis during dynamic conditions and calculates a medial lateral stability index (MLSI); an anterior-posteriorstability index (APSI); and an overall stability index(OSI),

measure gross motor function. higher scores indicate better outcome. scores are reported in percentage.

measure isometric muscle strength of knee flexors and extensors. higher scores reflect better outcome