After completion of this chapter, the physical therapist should be able to do the following:
Proprioceptive neuromuscular facilitation (PNF) is an approach to therapeutic exercise based on the principles of functional human anatomy and neurophysiology.1,12,78 It uses proprioceptive, cutaneous, and auditory input to produce functional improvement in motor output, and it can be a vital element in the rehabilitation process of many conditions and injuries.78 It is a manual therapeutic technique that is widely used by clinicians in multiple aspects of injury rehabilitation.89
The therapeutic techniques of PNF were first used in the treatment of patients with paralysis and various neuromuscular disorders in the 1950s.84 Originally, PNF techniques were used for strengthening and enhancing neuromuscular control.15,28,31,58,79 Since the early 1970s, PNF techniques have also been used extensively as a technique for increasing flexibility and range of motion (ROM).10,11,19–21,35,39,41,55,66,82,87
This discussion should guide the physical therapist in using the principles and techniques of PNF as a component of a rehabilitation program.
PNF AS A TECHNIQUE FOR IMPROVING STRENGTH AND ENHANCING NEUROMUSCULAR CONTROL
Original Concepts of Facilitation and Inhibition
Most of the principles underlying modern therapeutic exercise techniques can be attributed to the work of Sherrington,76 who first defined the concepts of facilitation and inhibition.
According to Sherrington, an impulse traveling down the corticospinal tract or an afferent impulse traveling up from peripheral receptors in the muscle causes an impulse volley that results in the discharge of a limited number of specific motor neurons, as well as the discharge of additional surrounding (anatomically close) motor neurons in the subliminal fringe area. An impulse causing the recruitment and discharge of additional motor neurons within the subliminal fringe is said to be facilitatory. Any stimulus that causes motor neurons to drop out of the discharge zone and away from the subliminal fringe is said to be inhibitory.49 Facilitation results in increased excitability, and inhibition results in decreased excitability of motor neurons.95 Thus, the function of weak muscles would be aided by facilitation, and muscle spasticity would be decreased by inhibition.22
Sherrington attributed the impulses transmitted from the peripheral stretch receptors via the afferent system as being the strongest influence on the alpha motor neurons.76 Therefore, the physical therapist should be able to modify the input from the peripheral receptors and, thus, influence the excitability ...