To determine the effects of aerobic training on spasticity and gross motor function in children with diplegic Cerebral palsy.Cerebral palsy (CP) is a neurodevelopmental disorder characterized by abnormalities of muscle tone, movement and motor skills, and is attributed to injury to the developing brain. . The spastic CP is found to be the commonest presentation followed by athetoid, ataxic and mixed types. Children with cerebral palsy (CP) have decreased capacity to participate in play and sports activities .Reduced capacity to perform typical childhood activities contributes to low habitual physical activity and declining gross motor function in adolescence. Exercise opportunities are restricted in the population of cerebral palsy with spasticity, and so muscle strength may be reduced by disuse. Aerobic Training via Lower-extremity cycling is a rehabilitation tool used by physical therapists to improve spasticity, gross motor function and cardio-respiratory fitness, appears well-suited as a therapeutic intervention for children with CP. The tools used will be GMFM-66 and Modified Ashworth Scale. Study will be conducted on Thirty two patients in two Groups. Group A will be Control Group that will be provided with conventional physiotherapy (Stretching exercises , Trunk control training, walk and breathing exercises) and Group B will be Experimental Group that will be provided with conventional physiotherapy with cycling for 30 minutes with three sessions per week over the period of 12 weeks. Data will be analyzed using spss 22.0.

Inclusion Criteria:

• 6-12 years of age both genders will be included.
• Ability to follow simple verbal instructions.
• Ability to walk independently, with or without an assistive device, for short distances (gross motor function classification system [gmfcs] levels i-iii)
• Spastic Diplegic Cerebral Palsy scoring on Ashworth Scale of 1, 1±, 2

Exclusion Criteria:

• Orthopedic surgery, neurological surgery, or baclofen pump implantation within the preceding 12 months
• Botulinum toxin injections within the preceding 3 months
• Serial casting or new orthotic devices within the preceding 3 months
• Initiation of oral medications that affect the neuromuscular system (eg, baclofen) within the preceding 3 months
• Inability or unwillingness to maintain age appropriate behavior
• Serious medical conditions such as cardiac disease, diabetes, or uncontrolled seizures
• Significant hip, knee, or ankle joint contractures preventing passive movement of the lower limbs through the pedaling cycle