The study aims to:

1. Investigate the effect of segmental trunk stability training on sitting in children with spastic CP.
2. Investigate the effect of segmental trunk stability training on upper limbs functions in children with spastic CP.

Postural dysfunction is one of the most limiting factors in children with CP. It restricts reaching skills and in turn reduces participation in activities of daily living.

The trunk plays a key role in maintaining the postural control mechanism and also in the organization of balance reactions in this developmental process. The trunk control is also required for a stable base of support which is necessary to execute functional activities for limb movements.

The optimal level of trunk support for a child with spastic CP still remains unknown. Thus, providing intermediate levels of trunk stabilization would be a better solution than providing full support in children with CP. Innovation is necessary to improve outcomes for children with moderate to- severe CP who are at level IV and V on GMFCS. However, these children are often excluded from posture research . Very little research has examined postural constraints in children with moderate-to-severe CP.

As there is a lack of tools used in precise trunk stabilization during training, a further researches are needed. Recently, a special attention has been given to the segmental trunk control and its effects on improvement of gross and fine motor skills. Most of previous studies have been applied during segmental fixation of the trunk at multiple levels from static position either sitting or standing. In the present study, the effect of external segmental stabilization of the trunk at selected parts will be monitored during the active training and participation of the child.

Inclusion Criteria:

1. Children with spastic CP, their chronological age will be ranged from 2 years to 4 years.
2. Their level of motor function will be 4 or 5 according to Gross Motor Function Classification System - Expanded and Revised
3. The degree of spasticity for these children will ranged from grade 1 to 2 according to Modified Ashworth Scale
4. All children's level of segmental trunk control will be level 3 according to Segmental Assessment of Trunk Control
5. They will be able to follow instructions during evaluation and treatment.

Exclusion Criteria:

• Any child with the following criteria will be directly excluded from the evaluation for the consistency of the sample and statistically obtained results: 1. Surgical interference in upper limbs and/or spine that may restrain the child performance during activities.2. Orthopedic problems or fixed deformities in the vertebral column and/or upper extremities. 3. Uncontrolled seizures. 4. Visual or hearing impairment.