Cerebral palsy patients (cerebral infirm motor or IMC in French) present kinematical and kinetic differences with normal subjects and between their own left/right sides. These kinematical differences can be in relation with segmental coordination differences. The aim of this study is to characterize such segmental organization between the shank and the thigh for a cerebral palsy child in order to compare this coordination between left/right sides with the method of relative phase. A population of healthy subject let to validate our method with Byrne et al.'s results [1]. A young cerebral palsy child constitutes our clinical population for this study. A motion capture system (Vicon250) was used in order to capture movements of shank and thigh in sagittal plane. All the subjects walk at their self-selected speed along a horizontal walkway (9m). The angular position and angular velocity (calculated from position) of the shank and the thigh are computed as Byrne et al. After validation of our healthy results with Byrne et al's ones, we can describe the patient's curves. For him, the same path is observed between left and right sides. However, right side globally leads the left side. An important part of the stance phase presents the same temporal organization between these two sides.