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What Is PNF Stretching?

Reviewed by Dan Brennan, MD on May 18, 2021

Proprioceptive neuromuscular facilitation (PNF) is a stretching technique that can improve your range of motion. Many therapists use PNF to help people regain their range of motion after injury or surgery. However, it can also be used by athletes and dancers to improve their flexibility.

PNF can help you strengthen your muscles, but can be risky if you’re not a professional athlete or dancer. Read on to learn more about how PNF stretching works.

What Is PNF Stretching?

PNF is a form of stretching that can boost your flexibility, range of motion (ROM), and strength. In particular, it can boost your passive range of motion (PROM) and active range of motion (AROM).

Developed at the Kabat-Kaiser Institute from 1946 to 1951 by neurophysiologist Herman Kabat and physical therapist Margaret “Maggie” Knott, PNF was initially developed for people with neurological conditions such as poliomyelitis. Later on, PNF expanded to treating musculoskeletal conditions.

The PNF stretching technique can also be used by athletes as well as non-athletes to improve performance. Studies have found that doing PNF stretches before exercise can boost performance in exercises such as jogging. However, PNF can decrease performance if done before high-intensity exercises such as weight-lifting and sprinting. 

Methods

When doing PNF exercises, you typically:

  1. Stretch a muscle group.
  2. Contract this muscle group against resistance while it’s still in the stretched position.
  3. Stretch the muscle group again.

Resistance is usually provided through the help of a partner.

There are three PNF methods: contract-relax (CR), contract-relax-antagonist-contract (CRAC), and hold-relax-swing.

Contract-relax (CR) method. Also known as the hold-relax method, this involves lengthening the target muscle and holding it in that position while contracting.

You can perform a CR stretch by following these steps:

  1. Start with a passive stretch. A passive stretch is when a muscle is lengthened while not being stimulated to contract. An example of this is the stretching feeling in your hamstrings when you reach down to touch your toes.
  2. Isometrically contract the muscle that’s being passively stretched for seven to 15 seconds. An isometric contraction is when you hold your muscle at a constant length.
  3. Relax the muscle for two to three seconds.
  4. Passively stretch the muscle again. This time, make sure your muscle stretches further than in step one. Hold for 10 to 15 seconds.
  5. Relax the muscle for 20 seconds before doing another PNF technique.

Contract-relax-antagonist-contract (CRAC) method. Also known as the hold-relax-contract method, the CRAC is similar to CR but focuses on antagonistic pairs of muscles. In an antagonistic pair, one muscle contracts while the other relaxes or lengthens. The muscle that’s contracting is the agonist, while the muscle that’s relaxing is the antagonist.

You can perform a CRAC stretch by following these steps:

  1. Do a passive stretch.
  2. Hold the muscle that’s being stretched in an isometric contraction for seven to 15 seconds.
  3. Relax the muscle while performing an isometric contraction on its antagonist. Hold for seven to 15 seconds.
  4. Relax the muscle for 20 seconds before doing another PNF technique.

Since there's no final passive stretch, the CRAC method is one of the safest PNF techniques to perform. 

Hold-relax-swing method. This technique involves ballistic or dynamic stretches combined with static and isometric stretches. It’s not recommended for beginners and should only be done by experienced dancers and athletes who have achieved a high level of control over their muscle stretch reflex.

It’s similar to the hold-relax technique, but a dynamic or ballistic stretch is done instead of a passive stretch.

Benefits of PNF Stretching

PNF stretching can improve your range of motion, or ROM. It can also boost your muscle flexibility and strength. 

Increase ROM. By stretching or lengthening the muscle spindles and Golgi tendon organs (GTO) through PNF, you can increase your ROM.

Research indicates that PNF stretching may be the most effective method of stretching to increase your ROM.

Boost muscle flexibility. Studies have shown that PNF can increase muscle flexibility. In particular, PNF can boost hamstring and lower leg (gastrocnemius) muscle flexibility.

Boost muscle strength. PNF can boost the strength of your muscles if done before less strenuous exercises. A study shows how vertical jumping and throwing distance can improve by more than double when athletes do PNF stretching twice a week for eight weeks.

Risks of PNF Stretching

You need to be careful with PNF stretching since you can easily twist and tear your muscles. If you’ve never tried PNF stretching before, you should seek out a professional trainer to make sure you know what you’re doing. 

PNF techniques like hold-swing-relax and its cousin, hold-relax-bounce, aren’t recommended for anyone who isn’t a professional dancer or athlete.

Anyone whose bones are still growing, such as children and teens, should not try out PNF stretching. Children and teens are usually already quite flexible, so PNF techniques may have a higher chance of damaging their connective tissues and tendons.

Show Sources

SOURCES:

International PNF Association: “About IPNFA.”

Journal of Human Kinetics: “Proprioceptive Neuromuscular Facilitation (PNF): Its Mechanisms and Effects on Range of Motion and Muscular Function.”

Massachusettes Institute of Technology: “Types of Stretching.”

MUSC Health Sports Medicine: "The Role of Muscle Proprioceptors in Proprioceptive Neuromuscular Facilitation (PNF) Stretching.”

Perceptual and motor skills: “Comparative study of static, dynamic, and proprioceptive neuromuscular facilitation stretching techniques on flexibility.”

Sports Medicine: “Proprioceptive neuromuscular facilitation stretching: mechanisms and clinical implications.”

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