By looking through the internet one is lead to believe that pnf stretching is all there is to PNF. Proprioceptive neuromuscular facilitation (PNF) is an effective way of using reflexes to assist muscular relaxation. Stretching using these principles is only one part of a system used by physical therapists to help muscular strengthening, stability, neuromuscular control, as well as mobility and coordination. This has been shown to be superior to static stretching in some literature.
facilitation (PNF) was first developed by Margaret Knott PT, and Herman
Kabat MD in the 1940's to treat neurological dysfunctions. This was an
attempt to gain better control in a population of neurologically
impaired instead of just offering the standard treatment at the time
which was range of motion exercises and gait training. Treatment
involved reeducation of developmental movements and postures. This
approach helped patients become more efficient in their movements and
activities of daily living.
Muscle recruitment is enhanced through the use of the appropriate reflex and proprioceptive stimuli. The efficient recruitment of motor patterns involves the use of the following PNF techniques:
PNF patterns of movements were developed because all normal coordinated human movements occur in spiral or diagonal motions. Muscular contractions are strongest and most coordinated during these diagonal patterns of movement. These diagonal patterns involve rotation of the extremities and require core stability. Muscular contraction is also enhanced through irradiation and there is optimal facilitation of the stretch reflex in a synergistic muscle group during movements within these patterns of movement.(2)
This is also known as "active assisted" stretching in some of the literature.
The golgi tendon organs lie in the tendon of a muscle that mediate the stimulation of inhibitory interneurons in the spinal cord that cause relaxation of that muscle's motor neuron. They also make excitatory connections with the motor neurons that supply the antagonists of that muscle. Since the golgi tendon organs are in series with the muscle fibers they are stimulated by both passive stretch and active contraction of the muscle. The golgi tendon organ therefore acts as a transducer in a feedback circuit that helps to regulate muscle force through inhibition and relaxation of the muscle.
The contract-relax technique uses the development of tension in a muscle by isotonic contraction to facilitate the relaxation and therefore stretch a muscle. By facilitating the relaxation of muscles we can improve circulation and improve extensibility of myofascial tissues. To accomplish this the muscle is placed in a maximally stretched position and resistance is applied to a muscle contraction of the muscle that is being stretched (direct contraction) or that muscles antagonist (reciprocal relaxation). Movement occurs during this contraction. Following this contraction the limb is relaxed and upon relaxation is actively or passively stretched further.
The hold-relax PNF stretching technique is used to facilitate the relaxation of muscles to gain range of motion. This method uses an isometric contraction rather than an isotonic one. To achieve this the limb is place in painfree range and an isometric contraction is sustained. The limb is then moved into the new range. The hold-relax method of PNF stretching is facilitated by the golgi tendon organ to allow a reflexive relaxation of the muscle. It can be done individually or with assistance from a trainer or physical therapist. The danger of the hold relax PNF stretching technique is that with this inhibition of muscle activity, it may predispose an athlete to injury if done prior to an athletic event.
The first part of this stretch is
similar to the hold-relax whereby the muscle being stretched is
isometrically contracted for 3 to 6 seconds, then the antagonist muscle
will immediately contract for 3 to 6 seconds. The joint is then pushed
into its new range.
PNF Stretching: The Role of the Stretch Reflex
The muscle spindle is a long thin nerve receptor found within the muscle. Information from this receptor transmits information to the spinal cord regarding muscle length and the speed of lengthening. When a muscle is stretched quickly this muscle spindle fires and causes a reflexive contraction within that muscle that is undergoing the stretch. The greater the speed of stretch, the stronger the reflex contraction in the muscle being stretched.
PNF Stretching: Reciprocal Inhibition
inhibition of the antagonist muscle group is mediated by the muscle spindle. If the agonist muscle contracts, then the spindle fires, sending messages to the spinal cord causing the antagonist muscle to relax.
PNF Stretching: Autogenic Inhibition
The golgi tendon organ is a nerve receptor found in tendons. This receptor fires when tension increases within the tendon. This tension can be due to stretch or contracting muscle. When the golgi tendon organ fires a signal is sent to the spinal cord causing the agonist muscle to relax.
During pnf stretching, these three mechanisms all work together to allow normal smooth movements and can be manipulated through PNF techniques to increase our ability to stretch.
1. Carter, A., Kinzey, S.,
Chitwood, L., & Cole, J. (2000). Proprioceptive neuromuscular
facilitation decreases muscle activity during the stretch reflex in
selected posterior thigh muscles. Journal of Sports Rehabilitation,
2. Knott, M., & Voss, D. (1968). Proprioceptive Neuromuscular Facilitation (2nd ed.). Harper & Row: Philadelphia.