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The Truth About PNF Techniques

Vol. 15 •Issue 26 • Page 40 The Truth About PNF TechniquesProprioceptive neuromuscular rehabilitation is more than just stretching and functional movementBy James R. Scifers, DScPT, SCS, LAT, ATCMention proprioceptive neuromuscular facilitation (PNF), and most clinicians think of stretching orfunctional movement patterns. While it is true that PNF focuses on stretching and functionalmovement, it is also much more. PNF techniques help develop muscular strength and endurance,joint stability, mobility, neuromuscular control and coordination–all of which are aimed at improvingthe overall functional ability of patients.Developed in the 1940s, PNF techniques are the result of work by Kabat, Knott and Voss.1-3 Theycombined their analysis of functional movement with theories from motor development, motorcontrol, motor learning and neurophysiology.1To that end, PNF techniques have broad applications in treating people with neurologic andmusculoskeletal conditions, most frequently in rehabilitating the knee, shoulder, hip and ankle.4Stretching TechniquesStretching is a main component of PNF. In fact, PNF stretching is superior to other stretchingtechniques.5-7

Neuromuscular inhibition procedures reflexively relax the contractile components of shortenedmuscles so patients can gain range of movement. Various techniques are used, among them:Hold-Relax. Familiar to most clinicians, this technique involves lengthening a tight muscle andasking the patient to isometrically contract it for several seconds.As the patient relaxes, the clinician lengthens the involved muscle further and holds the stretch atthe newfound end-range of motion. This technique relies on the firing of the Golgi-tendon organ(GTO) to cause reflexive muscle relaxation. It's easily applied and can be incorporated in homeexercise and preventive programs.But while activating the GTO can increase flexibility, it also may predispose the patient to injury.Specifically, PNF stretching can decrease activity of selected hamstring muscles. A suddenstretch, which might occur during functional activity, may predispose patients to increased risk ofmusculotendinous injury, if PNF stretching is applied directly before activity.8Hold-Relax with Agonist Contraction. This technique follows the same procedure as the Hold-Relax technique. However, after the tight muscle is contracted isometrically against the clinician'sresistance, the patient concentrically contracts the muscle opposite the tight muscle to activelymove the joint through the increased range.1 The clinician then applies a static stretch at the endof this new range of motion and repeats the process several times.Agonist Contraction. With this stretch, the clinician passively lengthens the tight muscle (theantagonist) to its end-range. The patient then concentrically contracts the muscle opposite thetight muscle (the agonist) to move the joint to a new position in the range of motion.1 The clinicianapplies mild resistance during this contraction, being careful to allow for movement through therange of motion. This technique uses reciprocal inhibition to encourage the tight muscle to relaxand lengthen during agonist muscle contraction.Of the three techniques, the Hold-Relax is the most frequently used.4 But over the last decade,the Hold-Relax with Agonist Contraction has gained popularity.4 Research indicates that sub-

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the Hold-Relax with Agonist Contraction has gained popularity. Research indicates that sub-maximal contractions that are progressive in intensity over the course of a rehab program increaseflexibility.9 For the best results, clinicians should use PNF stretching early in the rehabilitationprogram and gradually increase the intensity of the contractions throughout the rehab process.While clinicians know the difference between the three techniques, they often intermixterminology. For example, many clinicians and authors refer to Hold-Relax stretching as Contract-Relax stretching. Some even incorporate a concentric contraction of the tight muscle againstminimal resistance before applying a second stretch.This procedure, however, is incorrect and doesn't allow for maximum gains in flexibility; any firingof the GTO is negated by the time the person moves the extremity back to the starting point of theconcentric contraction.Strengthening TechniquesAlong with stretching, PNF strengthens the body through diagonal patterns, often referred to as D1and D2 patterns. It also applies sensory cues, specifically proprioceptive, cutaneous, visual andauditory feedback, to improve muscular response.1 The diagonal movements associated with PNFinvolve multiple joints through various planes of motion. These patterns incorporate rotationalmovements of the extremities, but also require core stability if patients are to successfullycomplete the motions.Two pairs of diagonal patterns exist.10 These patterns can be performed in flexion or extensionand are often referred to as D1 flexion, D1 extension, D2 flexion or D2 extension techniques forthe upper or lower extremity.1 Although patients can perform these patterns with many forms ofresistance, the interaction between patient and clinician is key to the early success of PNFstrengthening.1This interaction requires manual resistance throughout the range of motion through carefullypositioned hand placement and appropriately choreographed resistance. By placing the handsover the agonist muscles, the clinician applies resistance to the appropriate muscle group, whileguiding the patient through the proper range of movement.1In using manual resistance, the clinician can make minor adjustments as the patient's coordinationimproves or fatigue occurs during the rehab session. In general, the amount of resistance appliedis the maximum amount that allows for smooth, controlled, pain-free movement throughout therange of motion.10 In addition to manual resistance strengthening, PNF diagonal patterns enhanceproper sequencing of muscular contraction, from distal to proximal. This promotes neuromuscularcontrol and coordination.1To enhance coordination, movement and stability, clinicians use numerous techniques during PNFexercises, among them:Rhythmic stabilization. This technique, which incorporates passive movement of the jointthrough the desired range of motion, is a teaching tool to re-educate the neuromuscular system toinitiate the desired movement. The technique begins with the clinician passively moving theextremity through the desired movement pattern at the desired speed several times. It thenprogresses to promote active assistive or active movement, with resistance, through the samepattern to help the patient improve coordination and control.Slow reversal. This technique involves a dynamic concentric contraction of the stronger agonistmuscle group. A second dynamic concentric contraction immediately follows, this time involvingthe weaker antagonist muscle group.1 Rest periods don't occur between contractions. Therefore,this technique promotes the rapid, reciprocal activities the agonist and antagonist muscle groupsneed for many functional activities.Slow reversal hold. This technique adds an isometric contraction (hold) at the end-range of eachmuscle group. It's especially beneficial in enhancing dynamic stability of the larger proximal musclegroups.Alternating isometrics. This technique encourages stability of postural trunk muscles andstabilizers of the hip and shoulder girdle. With alternating isometrics, the patient "holds" hisposition, while manual resistance is alternately applied in a single plane from one side of the bodyto the other. No motion should occur.Instead, the patient should maintain the starting position of the involved limb. This technique canstrengthen the trunk, a single extremity or bilateral extremities, and can be applied with the limbsin the open- or closed-kinetic chain.

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in the open- or closed-kinetic chain.Alternating rhythmic stabilization. This technique is simply an extension of alternatingisometrics in which the involved muscle groups co-contract. Rhythmic stabilization is mostcommonly performed in a closed-chain position to further enhance muscular co-contraction andjoint stability.1With this technique, the clinician applies manual isometric resistance in a multidirectional pattern.The clinician may apply simultaneous manual resistance in multiple directions, forcing the multiplemuscle groups to contract simultaneously to support and stabilize the extremity. This technique isparticularly beneficial in isometrically contracting the proximal joint rotators.1PNF exercises can be applied to patients of all ages. Klein et al. found that using PNF techniquesfor older adults improved range of motion, isometric strength and selected physical functiontasks.11

Additional studies have shown that PNF stretching is superior to static stretching in improvinghamstring flexibility in people 45 to 75 years of age.12

One study compared PNF stretching to static stretching in active seniors. While static stretchingand PNF stretching yielded gains in hamstring flexibility, PNF stretching was most beneficial inparticipants younger than 65.13

Still another study demonstrated the value of PNF stretching vs. static stretching when comparingthe techniques in Special Olympic athletes.14

Whether promoting flexibility, developing muscular strength and endurance, improving jointstability or increasing neuromuscular control and coordination, PNF is a valuable part of everyrehabilitation program. Proprioceptive neuromuscular facilitation encompasses all aspects of therehabilitation process—and can help patients with various dysfunctions achieve their goals.References are availale at advanceweb.com/pt; click on the references tool bar.James R. Scifers is program director for the athletic training education program at WesternCarolina University in Cullowhee, NC. He is a practicing athletic trainer and board-certifiedspecialist in sports physical therapy.

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