Shock waves are single pressure pulses of high pressure ranging from 400-1200 atmospheres. Their duration is only one microsecond, that is the millionth part of a second. A pressure registration of a shock wave is shown is the figure (source: Shock wave laboratory of the University of Stuttgart in Germany, group of Professor Eisenmenger: Ultrasonics 1993;31:267-273). The rise time of the pressure pulse (in the left part of the figure) has only a duration of a billionth second. The pressure pulse is always followed by a tensile wave(in the middle of the figure). This is important to note because it helps to understand how shock waves act in the body.