The adaptations in kinematics and muscle activity, investigated by 3D gait analysis and dynamic electromyography recordings, will be studied in children with bilateral spastic cerebral palsy during level walking, and before and after a training on a treadmill with a sloped surface (7°). Data will be compared with those obtained in a sample of typically developing (TD) children (controls)

15 CP children and 15 TD children aged 6 to 14 years will take part in this study. Dynamic EMG recordings will be performed as well as kinematic data assessments through a gait analysis system. Three different slopes will be assessed, using a treadmill. The primary outcome measure will be the minimal knee extension value in the stance phase. The changes in kinematics will be overall assessed through the Gait Profile Score (Baker et al.). The details in changes will be assessed through statistical parametric mapping (SPM). The changes in muscle activity induced by the slope will be investigated by statistical parametric mapping of the EMG or kinematic data.

Inclusion Criteria for children with CP:

• age = 6-14 years old
• children with cerebral palsy: spastic type, bilateral involvement, forefoot initial contact and/or excessive knee flexion at mid-stance and/or decreased hip extension in late stance.
• GMFCS I or II,
• Score on Gillette scale between 8 and 10
• able to walk at least 10 min without help

Inclusion Criteria for TD children:

• age = 6-14 years old

Exclusion Criteria:

• botulinum toxin injection or lower limb surgery within the last year.
• Uncontrolled seizures