Anyone just read that and wonder: What is PNF stretching? What does PNF even mean? How is it so different from regular stretching? You’re not alone.

Usually when someone stretches, they take a target muscle, such as their hamstring, and they put it in a lengthened position (think touching your toes), hold it for 10-15 seconds, then return it to its initial position. This type of stretching is known as static stretching.

Static stretching is what most of us are accustomed to doing when we feel stiff or after a good workout. PNF stretching, as you will soon see, works differently and is much more beneficial for you than a typical static stretching routine.

PNF is short for proprioceptive neuromuscular facilitation. It’s a mouthful—essentially, what this means when we talk about PNF stretching, is using the neuromuscular system of the body to achieve greater range of motion at a joint. This stretching technique utilizes both the stretching and contracting of the targeted muscle to increase range of motion. The literature on PNF stretching lists a variety of benefits; these benefits include:

  • Increased Joint range of Motion
  • Increased Muscular Flexibility
  • Increased Muscular Strength
  • Increased Neuromuscular Efficiency
  • Decreased Muscular Hypertonicity

There are a couple of scientific papers concluding that PNF stretching is superior to increasing joint range of motion and increasing muscular flexibility when compared to traditional static stretching. Now, how and why is this the case, you might ask? There are three main mechanisms that researchers think might be at play while PNF stretching is occurring; they are: autogenic inhibition, reciprocal inhibition, and stress relaxation.

Let’s break these down so you can gain a better understanding of what’s really going on.


Autogenic Inhibition

This is the reflexive relaxation of the muscle after built up tension from a stretch. It’s the body’s natural protective mechanism utilized by the Golgi Tendon Organs in the musculotendinous junction, which detects this tension in the muscle. If our muscles didn’t have this protective function, we would be dealing with a lot more tears in the muscle anytime the muscles go through a stretch.


Reciprocal Inhibition

This is the relaxation of the muscle opposite to the muscle that is being contracted. The brain and body do this naturally when we want to move a particular part of the body. Take your arm, for example, if you wanted to do a bicep curl, your triceps muscle would need to relax so the biceps could move the arm effectively. If this didn’t happen, the arm would lock up with no way of being mobile.


Stress Relaxation

The musculotendinous unit of the muscle is made from viscoelastic properties. The viscous property of muscle will allow for the muscle to deform and change length with an external force applied to the muscle. The elastic property will allow the muscle to return to its normal length once the external force has been removed. Therefore, these properties allow the muscle to undergo mechanical stress in a linear fashion but can return to its normal form after the stress has been removed. However, if there is a low magnitude stress, such as a stretch applied to the muscle in a longer duration, the viscoelastic properties will adapt with it and lengthen. Simply put, stress relaxation is the musculotendinous unit of muscle relaxing after being under a constant linear “stress.”  This concept is known as “creep” and is utilized ALL THE TIME in stretching protocols. It would make sense that this would also occur in a PNF stretching routine.

The Three Types of PNF Stretching:

Yes, there are different types of PNF Stretching. They are all proven in clinical studies to have significant efficacy for improving joint range of motion and muscular flexibility, but the protocols for each of these are very different. The following are the different types and how they’re performed:

Hold-Relax

This technique is where you put the target muscle through a stretch and then perform an isometric (same length, no movement) contraction of that muscle. One example of an isometric contraction would be doing a bicep curl exercise but without the “curl” part. Think holding a dumbbell at with your elbow bent but not moving up or down.

Contract-Relax

This technique puts the target muscle on stretch, then uses an isotonic (through the full range) contraction of the same muscle instead of an isometric contraction to achieve a greater stretch.

Hold-Relax with Agonist Contraction

This technique puts the target muscle on stretch, then uses an isometric contraction of the muscle that is being stretched and an isotonic contraction of the muscle opposite of the muscle being stretched.

What’s important to note is that you don’t have to utilize all three techniques described to do PNF stretching. Pick one that works for you and you’ll be doing PNF stretching!

When and how to do PNF Stretching

There are two ways to perform PNF stretching. You could either a) perform it on your own or b)perform therapist/trainer assisted. PNF stretching technique is typically used post-exercise or on your rest day. If you are looking to get the maximal benefit from these techniques, they should be incorporated 2-3 times per week.

The type of PNF Stretching you would do alone is the Hold-Relax PNF stretching. The Contract-Relax or the Hold-Relax with Agonist Contraction techniques could be performed on your own, but they are much more difficult to do without a therapist or trainer assisting you. Here’s a simple step by step guide to doing PNF stretching on your own:

  • Pick a muscle you want to target
  • Put that muscle through a comfortable stretch
  • Hold for 15 seconds
  • Perform an isometric (same length) contraction of that target muscle for 6-7 seconds. This contraction should be 50-70% of your maximum.
  • Relax the muscle and go deeper into a comfortable stretch
  • Repeat steps 3-5 three times

How can we help

As an athletic therapist, I’m trained in the protocols and implementation of PNF stretching for any of my clients in need of it. As indicated by the evidence available in various literary sources, I believe that this stretching technique is an important tool to use post-exercise to increase your mobility and flexibility. I would HIGHLY recommend seeing someone trained in PNF stretching and the protocols before attempting on your own. This is a more advanced type of flexibility training and can lead to injury if you don’t know how to utilize the technique properly. I’ll be able to preform this technique for you in a safe and effective manner while showing you how to implement it on your own.

If you are interested in learning more about PNF stretching and its benefits, or if you are looking to experience it first hand, be sure to reach out to us at info@sandboxfitness.com.

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LinkedIn: Justin Vautour CAT(C), CSCS

References:

Hindle, K., Whitcomb, T., Briggs, W. and Hong, J., 2012. Proprioceptive Neuromuscular     Facilitation (PNF): Its Mechanisms and Effects on Range of Motion and Muscular Function. Journal of Human Kinetics, 31(2012), pp.105-113.

Lim, W., 2018. Optimal intensity of PNF stretching: maintaining the efficacy of stretching while ensuring its safety. Journal of Physical Therapy Science, 30(8), pp.1108-1111.

Lima, C., Ruas, C., Behm, D. and Brown, L., 2019. Acute Effects of Stretching on Flexibility and Performance: A Narrative Review. Journal of Science in Sport and Exercise, 1(1), pp.29-37.

Maddigan, M., Peach, A. and Behm, D., 2012. A Comparison of Assisted and Unassisted Proprioceptive Neuromuscular Facilitation Techniques and Static Stretching. Journal of Strength and Conditioning Research, 26(5), pp.1238-1244.

Yuktasir, B. and Kaya, F., 2009. Investigation into the long-term effects of static and PNF stretching exercises on range of motion and jump performance. Journal of Bodywork and Movement  Therapies, 13(1), pp.11-21.