There are basically four different way to produce the ‘shock wave’, which, without getting technical about it are : spark discharge; piezoelectric; electromagnetic and pneumatic (or electrohydrualic). The wave that is generated will vary in its energy content and also will have different penetration characteristics in human tissue. In therapy the most commonly employed generation method is based on the pneumatic system, and the key reason for this is that a radial (dispersive) wave results. The focussed waves are essential for ‘surgical’ interventions, but given their destructive nature, they are less appropriate for therapeutic uses. Focussed waves are sometimes also referred to as ‘hard’ shockwaves, the radial or dispersive wave sometimes called a ‘soft’ shockwave (another twist in the terminology).