A FitPro Guide to PNF Stretching

This blog will teach you about PNF stretching and how to instruct a PNF stretch with your clients to help them achieve their goals

You’ll discover:

  • What is PNF stretching?
  • 5 benefits of PNF stretching
  • How to do a PNF stretch?
  • Three Mock Questions to STRETCH your knowledge

What is PNF stretching?

There are many methods to stretching but I want to focus on Proprioceptive neuromuscular facilitation (PNF) and how this method exploits the above. 

PNF (proprioceptive neuromuscular facilitation) techniques involve a partner actively stretching the participant by some combination of altering contraction and relaxation of both agonist and antagonist muscles.  

Some of the different PNF techniques used include slow reversal hold, contract-relax, and hold relax.

PNF stretching is capable of producing greater improvement in flexibility compared to other techniques.

Its disadvantage is that it typically requires a partner, although stretching with a partner may have some motivational advantages for some individuals.  

Top 5 benefits of PNF stretching:

1. Rectify muscular imbalances and correct poor posture – which is exacerbated by sitting down a lot. Stretching commonly tight muscles (including the chest, hip flexors, hamstrings, adductors and low back) will help correct common postural deviations.

 2. To improve flexibility and avoid back pain. The lower back, hip flexors, and hamstrings are commonly tight, which can cause mild cramping feeling and “Knotts” inside the muscle.

This results in a downward spiral of poor blood flow, cramping, pain, and tightness. Stretching these regularly to help avoid lower back pain.

3. To avoid injury – by taking the muscle through increased ROM whilst controlled, your client is less likely to get injured by sudden movements or their exercise programme.

4. To release built up toxins – tight muscles create a network of tangled muscle fibres, which traps toxins.

Stretching realigns the fibres and helps to release these back into the blood flow, so they can be flushed out of the body.

5. Improve performance. Stretching a muscle to full range will “switch off” the muscle. Therefore, stretching the Antagonist of the targeted muscle during a warm up could encourage activation of the targeted muscles in your workout – for example, try stretching the hip flexors before a squat or running session – to really improve glute activation.

What happens to the muscle when we stretch?

We know why every client should stretch, but what happens physiologically when we stretch?

The muscle attaches to a bone via a tendon having crossed a joint;

a muscle contracts and pulls on the bone which now changes the angle of the joint. 

If the muscle is tight, it’s constantly shortened and therefore pulling on the bone which physically limits ROM at the joint. 

In contrast, if the muscle is weak or inactive, the joint is heavily compromised and ROM can be excessive. 

Within the Tendon there are Golgi Tendon Organs (GTO’s) and within the muscle there are muscle spindles. 

These two influence flexibility and stretching because of the reflex actions that they stimulate. 

Let’s dig a little deeper >>

What is a Muscle Spindle?

Muscle spindles are located within muscle fibres and their main function is to send messages back from the muscle to the central nervous system to inform about its state of stretch (length of the muscle). 

If the muscle is stretched, distortion of the muscle spindles causes a ‘myotatic reflex’ (automatic contraction) to come into play, thus avoiding damage through overstretching or miss-use of the muscle. 

This muscle spindle activation (muscle contraction) is felt as the “pull” during a stretch. 

The amount and rate of contraction elicited from the stretch reflex are proportional to the amount and rate of stretching.  Hence, the faster and more forceful the stretch, the faster and more forceful the reflex contraction of the stretched muscle; therefore, the greater the likelihood of the muscle tearing (particularly in an untrained muscle).

What is a Golgi Tendon Organ?

GTOs are proprioceptors located near the musculotendinous junction ( where muscles and tendons join). 

They are activated by a contraction in a muscle and help prevent excessive tension occurring within the muscle, or the tendon of that muscle. 

In contrast to the muscle spindles, stimulation of the GTOs will cause a reflex contraction of that muscle (the inverse stretch reflex).  This resulting relaxation is important for certain stretches because the inhibition of the muscle in which they are located, will allow muscle fibres to lengthen and stretch further.

Relaxation that occurs in the same muscle because of GTO activation called autogenic inhibition. 

This is achieved by contracting a muscle immediately before passively stretching it.  The contraction will increase GTO activation, thus increasing the subsequent muscle relaxation during the stretch.  Reciprocal inhibition is the relaxing effect that occurs in a muscle when the antagonist is contracting. 

This occurs to allow an easier contraction of the antagonist.  Hence, contracting the antagonist’s muscle will allow for a greater stretch in the muscle being elongated.

How to do a PNF stretch?

PNF stretching usually involves a 10 second push phase followed by a 30 second relaxation phase, typically repeated a three times.

Check out our lying hamstring PNF example >>


  • Your participant must be thoroughly warm first. Instruct your client to lie on the floor or mat.
  • Kneel beside the client and extend the client’s leg upward. Position the back of the client’s lower leg on your nearest shoulder.
  • Hold the client’s foot and just below the above the knee.  Your clients resting leg can be straight or bent here, and arms spread to the side so they are evenly positioned and can push through the floor.
  • Make sure your back is kept neutral.


  • Your client should feel a stretch and have a totally straight leg.
  • Hold here for 20-30 seconds or until tension fades.
  • Ask your client to push against your shoulder with approximately 40-70% of their strength, using their hamstrings isometrically.  
  • Hold this isometric contraction for 10seconds and then ask them to relax.
  • As they relax gently push your participant’s leg in the direction towards their chest, to increase the stretch.
  • Hold this stretch for another 20-30secs or until tension fades, then repeat the contraction and relaxation phases for 3-4 intervals.
  • Every stretch phase should increase the range of movement gradually.
  • Once the intervals have completed, shake out your client’s leg and remember to do the same on the other leg.

PNF stretching is a great way to develop flexibility and you will see immediate and long-lasting results with your clients. Make sure you monitor intensity throughout and only do PNF once fully warm

Test your knowledge with 3 stretching Mock Questions

Look at the 3 stretching Mock questions below and jot down your answer on a scrap paper or as a note in your phone.

Then scroll down to reveal the answers.

[NOTE: The answers are below the 3rd questions]

1. Which propriocetpor senses length in the muscle?
A. Golgi Tendon Organ
B. Muscle Spindle
C. Actin and Myosin
D. Baroreceptors

2. What does the acronym PNF stand for?
A. Peripheral Nerve Firing
B. Propriocetive Neural Familiarisation
C. Painful Neural Faciliataion
D. Proprioceptive Neuromuscular Facilitation

3. What is NOT a benefit of regular flexibility work?
A. Lower risk of injury
B. Improved performance
C. Tighter muscles around a joint
D. Correction of postural compensations

What’s the CORRECT answer?

Answers to the mock questions are :

Question 1= B, Question 2 = D, Question 3 = C

If you want more mock questions like this, then you can download more Free Mock Questions: DOWNLOAD NOW

Mock Questions

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Hayley “PNF stretching” Bergman

Parallel Coaching

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More blogs about stretching >> HERE