During the acquisition of posturokinetic abilities such as walking, postural control of the trunk is of paramount importance. Indeed, its development is strongly linked to the overall motor function of children. In cerebral palsy (CP), a term that refers to a set of motor disorders following a perinatal lesion, deficits in axial control are present from early childhood. These deficits are strongly correlated with the functional deficits observed in this population. In particular, during walking, deviations of the trunk (amplitudes, accelerations) are observed in the three planes of space. While recent literature increasingly questions the impact of trunk control deficit on the walking of children with CP, elements are still missing for a holistic understanding of the interaction between locomotor and postural disorders in children with CP. In particular, no study has focused on the deviations of trunk control and the center of mass (which is a global indicator of balance strategies) during the development and maturation of walking in children with CP. Therefore, the primary objective of this cross-sectional observational study will be to characterize the development of trunk control and center of mass during walking in children with CP.