Proprioceptive Neuromuscular Facilitation (PNF) encompasses a broad therapeutic approach to facilitate proper muscle function. There are many methods in this generic term.
Some methods are designed to strengthen muscles while other methods are designed to release restricted neuromuscular patterns. Many physiotherapists learn the first mentioned methods, while massage therapists can be trained in the latest methods.
PNF methods have been first designed by Herman Kabat, MD, PhD, Margaret Knott, PT, and Dorothy Voss during the 1940s and 1950s, and were based on the neuromuscular theories of Sir Charles Sherrington at the turn of the century. Sherrington’s laws of neurology, including irradiation, sequential induction, and reciprocal inhibition, became the basis of the earliest methods of treating PNF.
Initially, PNF was used to help patients paralyzed due to polio and associated injuries. Years later, PNF methods were used by physiotherapists as a supportive treatment option in movement and therapeutic exercises.
Benefits of stretching
PNF methods complement the traditional stretches performed by massage therapists. According to the Mayo Clinic, the top five benefits of stretching are:
• Increased flexibility and range of motion. Flexible muscles can improve your daily performance. Daily functional tasks become easier and less tiring. Flexibility tends to decrease with age, but can be regained and maintained.
• Improved circulation. Stretching increases blood flow to your muscles. Improved blood flow brings more nourishment, removes metabolic waste from tissues, and shortens injury recovery time.
• Better posture. Good posture relieves painful discomfort and chronic maintenance patterns in the body. When long-standing chronic tension has eased, the body’s parasympathetic mode can restore homeostasis.
• Stress relief. Stretching relaxes the tense, tense muscles that often accompany stress.
• Improved coordination. Maintaining a full range of motion with the joints helps you stay in better balance. Coordination and balance will keep you mobile and less prone to injury from falls, especially as you age.
Examining the anatomy and physiology involved in PNF methods explains how the use of PNF will bring these benefits. There are two key principles that work in conjunction with PNF style stretches: reciprocal inhibition and post-isometric relaxation. These principles allow PNF-style stretches to use the efficiency of the nervous system to enhance the effects of traditional simple stretches. Any section can be improved with the applied PNF methodology.
Reciprocal inhibition: This principle describes how a muscle relaxes when its antagonist contracts. Neurologically, an afferent (sensory) message from a muscle is brought into an interneuron in the spine. Because interneurons are inhibitory in nature, the efferent (motor) signal from the spine will stop the muscle antagonist from contracting.
Example: The anterior deltoid muscle, a flexor of the shoulder, relaxes when the posterior deltoid, an extensor of the shoulder, contracts.
Isometric post relaxation: This principle describes the three to five second window of time during which a muscle relaxes completely after stopping its contraction before muscle tone is restored. This allows the body to reset its proprioception.
What happens during a PNF stretch?
When you stretch a muscle for the first time, not all of the fibers stretch simultaneously. Some remain at rest. The length of an entire muscle depends on the number of stretched fibers.
When stretching occurs, two types of mechanoreceptor cells are at work: the Golgi tendon organs and muscle spindle cells. These cells perceive the position and movement of one’s own body by detecting changes in stress on the joints and muscles.
Golgi tendon organs are effective in ensuring that a muscle is not overworked. These cells communicate within the gray matter of the spine. When the gray cells perceive that a muscle may be damaged due to excessive load, the spinal cord sends a message to the muscle to relax. This is called a reverse stretch reflex.
Muscle spindle cells help maintain muscle tone and ensure that our muscles never stretch too much. These cells also communicate with the spinal gray matter. When the gray cells sense that a muscle is stretching beyond its limit, the spinal cord sends a message to the muscle to contract slightly. This is called a myotatic stretch reflex.
In addition, the articular nervous organs of Pacinian and Ruffini have an impact on the ability of the joints to remain stable and static during stretching. Pacini’s organs are active with rapid and rapid joint movements. Ruffini’s organs are active with slower and measured joint movements. If these organs cannot facilitate proper signaling, stretched joints may exhibit a feeling of abrupt or interrupted ending, the sensation experienced when a limb is stretched to its limit.
If the stretch is done slowly on a daily basis, the mechanoreceptor cells get used to the new proportions of length in the muscles. This is why daily stretching is essential for achieving optimal results from improving flexibility and range of motion.
[Visit the International PNF Association’s Open-Access Research Page for literature on PNF.]
Depending on the PNF method used, a practitioner may choose to engage a muscle with isometric or concentric muscle contraction. An isometric contraction involves a muscle held in a fixed position while it contracts. A concentric contraction involves muscle shortening as it contracts. Whether the contraction is isometric or concentric, only a slight contraction (about 10% of the offered force) is enough to engage the nerve cells involved to make PNF methods effective.
Full-strength contractions can easily lead to injury during treatments and are unnecessary to achieve the goals of PNF methods. Advising a client to exert a slight contraction to the maximum will avoid injury when stretching the PNF.
There are many types of PNF methods that can be learned. Physiotherapists will learn methods to strengthen muscles affected by injury, trauma and / or medical conditions.
These strengthening methods will help clients who need a greater range of motion to build muscle strength and endurance, as well as better continuity between agonist and antagonist muscles. Clients who are recovering from an injury will benefit greatly from improved muscle strength after the onset of muscle atrophy.
Physiotherapists and massage therapists can learn PNF methods to relax certain muscle regions for similar benefits. Clients with chronic pain will benefit from the relaxation effects provided. Functional improvements in daily tasks will be seen as the muscles improve their efficiency. Improved joint and muscle flexibility will promote proprioception and movement patterns, especially in people who are relearning to walk and use their bodies after an accident.
About the Author:
Jimmy Gialelis, LMT, BCTMB, is the owner of Advanced Arts and Education in Massage in Tempe, Arizona. It is a National Certification Board for Therapeutic Massage and Approved Continuing Education Provider of Bodywork, and teaches “Professional Ethics for LMTs” and many other continuing education courses. He is a regular contributor to MASSAGE magazine and his articles include “Massage for Trauma: 3 Ways of Responding to an Emotional Release” and “Diabetes and Massage: What Therapists Need to Know” (both, massagemag.com).
• “Facilitated Extensions”, McAtee, Robert & Charland Jeff, 1999, second edition.
• Mayo Clinic: https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/stretching/art-20047931, Staff, January 2020.