This study reports the first results of a research aimed to investigate how segmental variation is conditioned by prosody in Italian, by examining the acoustic and articulatory properties of syllables that are prominent at different levels of the prosodic hierarchy. We examined lip movement kinematics of unstressed, stressed and nuclearly accented syllables in order to understand the kinematic characteristics of accent-induced articulatory strenghthening. The kinematic results are then interpreted within a Task Dynamics model to evaluate how prosodically-driven variation can be accounted for by a particular dynamical parameter setting in a mass-spring gestural model.