A pistoncylinder unit having a selectively inhibited movement includes a cylinder filled with a hydraulic medium and a piston arranged on a piston rod and dividing the cylinder into working spaces. A driver DRV of a main switching device uses a PLL circuit PLL to apply frequency tracking control in such a manner that a driving frequency fsw is made to track a resonant frequency fr and that the phase of the driving frequency fsw leads the current zero phase of the resonant frequency fr always by a desired time. An opening can be formed in the membrane such that the membrane can act as a mask layer to the underlying wall surfaces and bottom surface of the cavity. An unprimed application is executed and an initialization signal is optionally communicated to the unprimed application. In a method for operation of a shockwave system for treatment of a patient, an indicator correlated with the calmness of the patient is detected and a measure to increase the calmness of the patient is taken dependent on the indicator. Preferably, the connection air pathway is provided with a valve mechanism for selectively isolating the connected rib strut from the leading edge strut.