Under water exercise program according to halliwick concept which will be applied as three sessions per week for three successive months. Underwater exercises will be performed under the supervision of a certified aquatic therapist. This practitioner will instruct the child in proper techniques for performing exercises while ensuring child's safety by using flotation devices, body boards or float belts when necessary. Also the pool where the children will perform underwater exercises will be equipped with ramps, chair lifts, stairs, and handrails to facilitate a child's ability to access the pool.

Conventional selected exercise program for 60 minutes , three sessions per week for three successive months aiming to improve the motor functions of the children in form of: (1) Neuro-developmental technique, (2) Back and abdominal exercises, (3) improving postural responses, (4) Flexibility exercises, (5) Strengthening exercise (particularly knee extensors, hip abductors and the ankle dorsi-flexors muscles) and (6) Improving standing, weight transfer and shift and finally facilitation of normal walking pattern .

The Halliwick Concept is a detailed swimming programme based on the scientific principles of body mechanics and the properties of water intended to educate individuals with special needs to be water safe and to move independently in the water as much as possible (Lambeck & Stanat 2001a).The programme consists of 10 specific progressive stages that are achieved without the use of floatation devices (Lambeck & Stanat 2001b).

The Gross Motor Function Measure (GMFM) is an observational clinical tool designed to evaluate change in gross motor function in children with cerebral palsy. There are two versions of the GMFM - the original 88-item measure (GMFM-88) and the more recent 66-item GMFM (GMFM-66) The scoring system of the GMFM is a four-point scale divided into five categories (lying and rolling; sitting; crawling and kneeling; standing; walking, running).