 It is a physiological principle stating that soft tissue heal according to the manner in which they are mechanically stressed.It is also an application of the Mechanostat model of Harold Frost which was originally developed to describe the adaptational response of bones; however – as outlined by Harold Frost himself – it also applies to fibrous collagenous connective tissues, such as ligaments, tendons and fascia.The "stretch-hypertrophy rule" of that model states