Gait abnormalities, which occur in Cerebral Palsy (CP), are characterized usually by a toe-to-floor or a plantar-to-floor initial contact (equinus gait), followed by an early braking of the tibia's forward progression (during ankle dorsiflexion). This causes consequently a trunk deceleration. Moreover, children with CP have difficulties to stabilize the trunk and the head in the space, and that could have impact on gait. If equinus gait is often attributed to the triceps surae spasticity, recent works suggest rather that this early braking of the dorsiflexion could be a motor adaptation to axial postural control difficulties. This thesis project aims firstly to attest that locomotor disorders are related to these difficulties in the stabilization of the axial body segments in children with CP and, secondly, to show that improving the trunk and head postural control with a specific rehabilitation protocol could reduce the early braking of the dorsiflexion and, consequently, the gait abnormalities observed in CP.

Inclusion Criteria:

• Gross Motor Function Classification System I or II
• no or minimal contracture of the triceps surae
• presence of soleus spasticity

Exclusion Criteria:

• botulinum toxin injections or surgery in the lower limb respectively in the 6 and 12 months preceding the study
• any modification of the physical or orthopaedic therapy within the last two months
• minimal hip flexion above 20° in a clinical examination
• pain in the lower legs when standing or walking