Purpose:The purpose of the study was to evaluate the effectiveness of respiratory muscle strengthening on trunk control in children with spastic diplegic cerebral palsy .

Subjects and Methods: Thirty children with spastic diplegic cerebral palsy aged from 8to 10 years selected with impaired trunk control and respiratory problems .They have spasticity degree of 1 to 2 according to modified Ashwarth scale. classified into 2 equal groups: control and study. Evaluation w by trunk control measurement scale and spirometer test pre and post treatment.Both groups will receive conventional program designed for diplegic cerebral palsy children in addition to incentive spirometer for study group and breathing exercises for control group for 1hour, three times per week for 1 month .

This study is a trial to evaluate the effectiveness of respiratory muscles strength on trunk control in children with spastic diplegic CP.

Inclusive criteria:

1. Children age ranged from 8 to 10 years old.
2. They were diagnosed as spastic diplegic cerebral palsy.
3. They had spasticity grade from1 to 2 according to modified Ashwarthe scale(appendix-II)(Balzer et al ,.2018) .
4. They had trunk control problems according to trunk control measurement scale (appendix-III)(Heyrman et al., 2011) .
5. They are able to follow orders and instructions.
6. They have respiratory function problems.

Exclusive criteria:

Children excluded if they had any of the following issues:

1. Having fixed deformities at lower limbs which affects sitting abilities.
2. Recent spine or lower limb surgeries or lower limbs Botox injection in the last six months before the study .
3. Moderate to sever scoliosis or spinal deformities.
4. Chest infection.