This study, using electromagnetic articulography (EMA), examines the supralaryngeal kinematics of bilabial voiced implosives in Central Vietnamese, focusing on lip aperture trajectories and gestural timing during stop formation and release. Results indicate that implosives exhibited a higher peak velocity away from closure, whereas their voiceless plosive counterparts were found to have a longer gestural plateau. To investigate whether these differences are inherently tied to implosivity or simply a consequence of voicing, we analysed voiced and voiceless bilabial plosives in Taiwanese Southern Min. The Southern Min data confirmed that voiced plosives did not exhibit the same rapid lip aperture movement, supporting the conclusion that, in the Central Vietnamese data, higher peak velocity away from the stop closure is a defining supralaryngeal feature of implosives.