It is used to increase range of motion and muscle elasticity.
In clinics, therapists use PNF to restore functionality of range of motion and muscle strength to patients who have received tissue damage or invasive surgeries.
PNF is more advanced stretching method than your regular stretching. Its purpose is to do two functions of muscle that are being targeted –
- Stretch it
- Contract it
They enhance muscles through the use of reflex and proprioceptive stimuli. Efficient recruitment of motor patterns involves use of the PNF techniques:
- Resistance – resistance applied to to muscle group will facilitate smooth motor response to muscle contraction and relearning. Different resistance levels vary to achieve motor response.
- Traction – Application of traction perpendicular to the arc of motion is used to facilitate an enhanced motor response
- Stretch Reflex – Stretch reflex is a stimulus that increases the state of responsiveness of a motor unit to cortical stimulation. This reflex is stimulated by fast elongation of the muscle. Stretch stimulates extrafusal and intrafusal muscle spindles to create a contraction. Muscle spindle and its reflex make a feedback device that works to maintain muscle length. Reflex makes a small window of isolated contraction, however with resistance can facilitate a muscular response.
- Manual Pressure – neuromuscular responses are influenced by contact with the skin and deeper pressure receptors.
- Irradiation – it is the overflow of neuronal excitation from stronger motor units to weaker ones, or units injury may inhibit that. This is done by applying graded resistance to larger muscle groups to enhance contraction in the weaker groups.
- And Approximation – a compressive force to approximate joint surfaces can facilitate a motor response and promote stability.
PNF Stretching Methods
We also know this as “active assisted” stretching in some literature.
The golgi tendon organs lie in the tendon of a muscle that mediate the stimulation of inhibitory interneurons in the spinal cord that causes relaxation of that muscle’s motor neuron.
They also make excitatory connections with the motor neurons that supply the antagonists of that muscle. Since the golgi tendon organs are in series with the muscle fibers, they are stimulated by both passive stretch and active contraction of the muscle.
The golgi tendon organ therefore acts as a transducer in a feedback circuit that helps to regulate muscle force through inhibition and relaxation of the muscle.
The contract-relax technique uses the development of tension in a muscle by isotonic contraction to facilitate the relaxation and therefore stretch a muscle. By facilitating the relaxation of muscles we can improve circulation and improve extensibility of myofascial tissues.
To accomplish this, we place the muscle in a maximally stretched position and apply resistance to a muscle contraction of the muscle that is being stretched (direct contraction) or that muscles antagonist (reciprocal relaxation).
Movement occurs during this contraction. Following this contraction the limb is relaxed and upon relaxation is actively or passively stretched further.
- Direct Contraction
For example, when stretching the hamstring, we place the hip in 90 degrees with the patient lying on his back. The knee is flexed against moving resistance isotonically and then relaxed.
The hip held at 90 degrees; we move the knee into its fully extended position to apply a stretch to the hamstring.
- Reciprocal Relaxation
For example, when stretching the hamstring, we place the hip in 90 degrees with the patient lying on his back. We then extend the knee against resistance, contracting the quadriceps.
The activity in the quadriceps causes reciprocal inhibition of the hamstrings, allowing for a greater stretch.
The hold-relax PNF stretching technique is used to facilitate the relaxation of muscles to gain range of motion. This method uses an isometric contraction rather than an isotonic one. To achieve this, we place the limb in pain-free range and it sustains an isometric contraction.
We then move the limb into the new range. The hold-relax method of PNF stretching is facilitated by the golgi tendon organ to allow a reflexive relaxation of the muscle.
It can be done individually or with help from a trainer or physical therapist. The danger of the hold relax PNF stretching technique is that with this inhibition of muscle activity, it may predispose an athlete to injury if done prior to an athletic event.
The first part of this stretch is like the hold-relax whereby the muscle being stretched is isometrically contracted for 3 to 6 seconds, then the antagonist muscle will contract for 3 to 6 seconds. It then pushes the joint into its new range.
Things That You Should Consider Before Engaging PNF Stretching
PNF stretching is advanced stretching technique so take caution before engaging.
Since PNF adds stress to the targeted muscle group, then there’s also possibility to damage soft tissue.
- Performing PNF stretching there is no need to apply maximum force, pressure or intensity, instead use gentle stretches and contractions. Aim for only half the force or intensity when executing PNF stretches – about 4/5 out of 10.
- Use more force for bigger muscle groups and less force on smaller muscle groups. If you are targeting smaller muscle groups like biceps, triceps and shoulders use only 3 or 4 out of 10.
- Before tackling the PNF warm up first! Warm up purpose is to get your body ready for more extreme physical activities. One benefit is that you get your body and muscle temperature to a level where it is safe to perform this kind of physical exercises. Also, it will grant maximum benefit.
PNF Stretching Benefits
- Muscles get relaxed, due to the fatigue in passive stretching phase.
- With time your coordination gets improved, this is due to practicing the movements.
- Overall flexibility through all body
- Stronger joints, perfect to prevent joint injuries.
- Balances strength, thanks to the strengthening and lengthening the muscle.
- Improves blood circulation to the muscles
- Increased overall performance, because of the increased blood flow, which in return increases oxygen levels that muscles receives.
- Increased range of motion and strength
- Repeated PNF stretching preserves muscle memory
- Similar benefits that of Yoga
PNF Stretching Precautions
- It is more painful than any other kind of stretching. Applying pressure and intensity to muscle groups can be painful, regardless you get out what you put in! You need to have strong mental game to do advanced stretching like PNF. It is worth it nonetheless!
- PNF stretching requires more work to be done, so you need to be motivated to tackle PNF.
- Rather dangerous, possible to get soft tissue damage if put too much pressure. In scale from 0 to 10 you shouldn’t pass the 6. Not all the pain from stretching is beneficial, therefore don’t over do it!
- Can’t do all the stretching by Yourself, simply because you won’t be able to reach all the areas on your body. But it’s no problem if you have someone to help you out!
- Always warm up your body before doing any kind of stretching
PNF stretching methods increases flexibility, performance, strengthens muscles and increases range of motion (ROM).
And considering all the benefits you get, the negative sides have little consequences when practiced with professional help. So We suggest that you try the PNF stretching routine.
- Take position in which your muscles you are targeting are being stretched and under tension.
- Contract stretched muscle for 5 seconds, while friend or immovable object, applies enough resistance to prevent movement.
- Contracted muscle group is relaxed with controlled stretch for 30 seconds.
- Mucle group you are targeting is allowed to rest and recover for 40 seconds.
- Repeat 3 or 4 times.
PNF Quad Stretch
- Lie down flat on your stomach
- Your friend or trainer puts his hand on your lower back while bending your leg upward pressing it toward your buttocks
- They stretch you out for 20-30 seconds and you try to resist for 5 seconds
- When you relax they push you for 20 more seconds
- Recover for 30 seconds
- Repeat for 3 more times
PNF Hamstring Stretch
- Lie on your back, while your training partner or friend lifts one leg up and holds it straight up pushing it slowly and gently towards your chest
- Maintain this stretch for about 30 seconds and after that resist for 5 seconds the stretch
- Take a rest and relax
- Stretch again for 30 seconds
- Do same thing for other leg
- Repeat for 3-4 times
PNF Chest Stretch
- Kneel on the floor with your back straight and with your arms tightly around back of your head
- Your training partner holds you by the elbows and gently pulls them backward towards themselves for 20-30 seconds
- Resist stretch for 4-5 seconds
- Finish the stretch by another 30 seconds of stretching
- Repeat for 3-4 sets