PlankvariationExtended plankCoreVideosExtended PlankFunctional BodybuildingExtended PlankJenny LaBawTEST YOUR CORE! Extended Plank.The Calisthenics SchoolMove hands further in front of you than shoulder-width to increase core activation. Muscles worked PrimaryAbdominalsExternal ObliqueInternal ObliqueObliquesRectus AbdominisTransversus AbdominisSecondaryAnterior DeltoidDeltoidsLatsPectoralis MajorSerratus AnteriorTriceps