Determine the effect of repeated pelvis perturbation training on trunk posture and locomotor function in children with CP.

We will determine whether repeat exposure to pelvis perturbation during sitting astride will induce functional improvements in trunk postural control and locomotion in children with CP.

Inclusion Criteria:

• Children with a diagnosis of bilateral spastic CP attributed to complications of prematurity, intracranial hemorrhage and periventricular leukmalacia according to the definition of Bax.
• Children aged 4 to 12 years old without Botulinum toxin treatment within 6 months, and without surgeries (such as selective dorsal rhizotomy) within 12 months before the onset of the training.
• Subjects will be able to remain seated without help for ≥10s.
• GMFCS levels will be I to IV.
• Children must be able to signal pain, fear or discomfort reliably.
• Children with mild scoliosis (Cobb angle < 20 °).
• Children with CP who have no prior hippotherapy experiences within 6 months.

Exclusion Criteria:

• severe lower extremity contractures, fractures, osseous instabilities, osteoporosis.
• severe disproportional bone growth.
• unhealed skin lesions in the lower extremities.
• thromboembolic diseases, cardiovascular instability.
• aggressive or self-harming behaviors.