A REVIEW OF THE NEUROPHYSIOLOGICAL AND VISCOELASTIC MECHANISMS ASSOCIATED WITH PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION
AbstractThis study involved a review of the mechanisms and theories associated with proprioceptive neuromuscular facilitation (PNF). Since the inception of PNF in 1952, by Herman Kabat, much of the literature identifies the changes in the nervous system as being responsible for the increase in range of motion (ROM) realised through this type of training. In contrast to the neural theorists, are those that attribute the gains in ROM to the viscoelastic or biomechanical properties of the muscle-tendon-fascia1 unit. Traditionally, high intensity muscular contractions have been used when performing PNF flexibility exercises. A maximal or near maximal effort was deemed necessary to activate the neuromuscular receptors which allow greater ROM before triggering reflex shortening. Studies using low intensity PNF exercise protocols and denervated animal tests of viscoelastic properties of the muscle-tendon-fascial unit, have yielded similar increases in ROM as the typical high intensity forms of PNF training.