What Is PNF Stretching?

Medically Reviewed by Ross Brakeville, DPT on June 18, 2023
4 min read

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 to improve their flexibility.

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

PNF 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. 

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 but with instruction, can easily be performed independently.

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 mild to moderate passive stretch for 7-12 seconds. 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 lying on your back, keeping one leg on floor and a partner lifting other up and back keeping knee straight.
  2. Isometrically contract the muscle that’s being passively stretched by pushing the leg back against the partner 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, increasing range. Hold for 7 to 15 seconds.
  5. Relax the muscle for 2 seconds before doing another contraction.
  6. Repeat this process 3-5 times.

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 in the same position as the CR technique above:

  1. Do a passive stretch of the leg with your partner.  Hold for 7–15 seconds.
  2. Perform an isometric contraction pushing back into your partner for seven to 15 seconds.
  3. Keeping your knee straight, have your partner hold your leg from moving while you try to lift it further back for 7–15 seconds.
  4. Relax the muscle for 2 seconds holding in the new position before doing another PNF technique.
  5. Repeat this process 3-5 times.

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 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.

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. 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.

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, are recommended for those trained first in contract-relax and contract-relax-antagonist-contract techniques.