When is pnf contraindicated

Toning, strengthening, and stretching your hip adductors…. Contrast bath therapy is a series of brief, repeated immersions in water, alternating between warm and cold temperatures.

According to research…. Health Conditions Discover Plan Connect. Medically reviewed by Peggy Pletcher, M. What is PNF stretching? How does it work? PNF techniques. How do I start? Helpful tips. Staying safe. Bottom line. Read this next. If the studies used did mention a theoretical mechanism, the discussions were brief. Few studies even mentioned the underlying mechanisms that cause the physiological changes within the body as a result of PNF.

Only one study provided an attempt to evaluate the theories behind PNF stretching. Thus, there has been no previous systemic review that intensely examined the proposed theories and the physiological changes occurring during PNF stretching that would result in the alterations in performance of certain outcome measures behind PNF stretching Sharman et al.

Therefore, this systematic review aims to break down the literature surrounding the physiological mechanisms and adaptations that occur during PNF stretching in order to provide a foundation upon which application of this technique will be validated, along with describing PNF as a means of gaining more ROM and helping to develop muscular strength and performance Nelson et al.

Four theoretical physiological mechanisms for increasing ROM were identified: autogenic inhibition, reciprocal inhibition, stress relaxation, and the gate control theory Sharman et al. Each of these theoretical mechanisms are reflexes that occur when the Golgi tendon organs GTOs in the tendons of the TM, or in the antagonist muscle to the TM, detect harmful stimuli such as a stretching sensation or during a contraction. Autogenic Inhibition is what occurs in a contracted or stretched muscle in the form of a decrease in the excitability because of inhibitory signals sent from the GTOs of the same muscle Sharman et al.

This tension causes activation of Ib afferent fibers within the GTOs. Afferent fibers send signals to the spinal cord where the stimulus causes the activation of inhibitory interneurons within the spinal cord.

It is theorized that this reflex occurs as the body attempts to spread the workload evenly across the motor unit within the muscle, assisting the asynchronous recruitment of the body in preventing specific motor units from fatiguing.

Although, there is uncertainty as to how much of a part GTOs play in PNF stretching, and the long term improvements seen in subjects as a result Sharman et al. Research has shown that GTOs have a major role in inhibition of muscle fibers, but the duration, and even the activation of this inhibition, is questionable.

Studies have shown that after contraction, the activation of the inhibitory neurons of the GTOs are low or nonexistent, showing that the inhibitory signal of the GTOs is weak after contraction Laporte and Lloyd, Note that muscle activation usually indicates movement or exercise, in which case muscle inhibition would be counterproductive.

Reciprocal inhibition is what occurs in the TM when the opposing muscle is contracted voluntarily in the form of decreased neural activity in the TM Sharman, It occurs when an opposing muscle is contracted in order to maximize its contraction force, in this case, the TM relaxes.

This relaxation of the TM is a result of the decrease in the neural activity, and the increase of inhibition of proprioceptive structures in the TM Rowlands et al. On a spinal level, Ia afferent fibers enter the spinal cord and give off collateral branches that interact with interneurons in the spine, which then send signals to the alpha-motoneuron in the GTOs of the TM.

The effect of this connection is inhibitory and causes relaxation of the TM The Nervous Statement, ; Sharman et al. The mechanism of PNF referred to above, is the way in which TM and its antagonist muscles work together. When one contracts, the other relaxes and is thus inhibited in order to prevent the muscles from working against one another Neuroscience Online, This inhibition of the TM, along with the shortening contraction of the antagonist muscle, allows the muscle fibers of the TM to elongate even further, creating a greater stretching force for the TM and producing a larger inhibitory influence on the TM Etnyre and Abraham, ; Sharman et al.

The interneuron that innervates the alpha-motoneuron, which synapses onto the TM, causes the neural activity in the TM to decrease and leads to more stretching of the TM Rowlands et al. More research on how long this reflex affects the TM needs to be done in order to prove reciprocal inhibition is behind the effects of PNF stretching. Stress relaxation is what occurs when the musculotendinous unit MTU , which involves the muscles and the connected tendons, is under a constant stress Sharman et al.

Both muscles and tendons have viscoelastic properties in which they exhibit characteristics of both viscous and elastic materials. A viscoelastic material both resists shear flow and strain linearly when stress is applied and returns to the original form once the stress is removed from the MTU. This decreases the force generated by the viscous material when it resists the elongation stimulus that stretching causes within the MTU.

Though, as the stretch is held, the stress relaxation occurs and there is a decrease in the passive torque and muscle stiffness that lasts for a short period of time Sharman et al. This is a protective mechanism to prevent muscle tearing and maintain a healthy relationship between the contractile units of the muscle sarcomere.

This is similar to the CRAC method, except for the fact that the contraction of the antagonist muscle applies more tensile force on the TM. Out of the four theories, the passive properties of the MTU is most applicable throughout each theory, as the viscoelastic properties of the muscle tissue itself allow for the muscle to be stretched and elongated as a result of the inhibitory signals, without substantial damage to the tissue during stretching.

In order for there to be an increase in ROM and flexibility, there needs to be an adaptation within the muscle. It is usually short lived, lasting anywhere from 80 seconds to an hour after PNF stretching Magnusson et al. Thus, although it seems as the viscoelastic properties of the muscle do account directly for the increased ROM experienced after PNF stretching, more research is needed on longer term adaptations to muscle tissue as a result of stretching for conclusive results.

The gate control theory is what occurs when two kinds of stimuli, such as pain and pressure, activate their respective receptors at the same time Mazzullo, Peripheral pain receptors are connected to either un-myelinated or small myelinated afferent fibers while pressure receptors are connected to larger myelinated afferent nerve fibers.

Each type of afferent fibers connect to the same interneurons in the spine, and because the pressure afferent fibers are larger and myelinated the pressure signals make it to the spine before the pain signals do when they are stimulated simultaneously Mazzullo, The inhibition of the pain signals happens in the dorsal horn when the large fibers transmit signals Melzack, A large force and stretch is produced in the elongated muscle when the participant resists the stretch.

This large force is sensed as noxious stimuli, and is seen as potentially damaging, which invites the GTOs to activate in an effort to inhibit the force and prevent injury. As this process is repeated with a consistent protocol, the nociception, or cause of the amount of inhibition of the GTOs, decreases as it becomes more accustomed to increased muscle and tendon length, as well as increased force.

The GTOs adapt and decrease inhibition, allowing the muscle to produce a greater amount of force; however, this may increase the risk of injury. With increased muscle length comes ability to produce greater force because of the length-tension relationship. With increased ROM, and decreased GTO inhibition, the muscle may be able to increase its strength and force production.

The gate control theory argues that when the muscle is stretched forcefully, past its natural ROM, the GTOs are activated in an attempt reduce injury. In PNF stretching, not only are the muscles and tendons stretched, they are also contracted at this elongated length, decreasing the nociception, or pain that is sensed that causes inhibition, produced by the GTOs. The GTOs adapt to the increase in length and force threshold, which allow for greater force production. Some evidence suggests that GTOs play no role in sensing force or inhibiting it Chalmers, If true, gate control theory would be discredited, however further investigation is needed to prove or disprove this theory.

Effects can last 90 minutes or more after the stretching has been completed Funk et al. The duration of these effects can vary because of various things, such as changes in the percentage of MVIC asked for and the duration of the contraction of the TM during PNF stretching Feland and Marin, ; Rowlands et al.

This contraction has been proven to produce better effects when held a total of 3—10 seconds, while six seconds is preferred Feland and Marin, It is necessary to know why six seconds is preferred and if there is any benefit to a longer or shorter contraction. There is an increase in ROM and flexibility found regarding each variance, but to different degrees. While there was a large amount of literature that solely looked at changes in ROM over time, or after one bout of PNF stretching, there was a limited amount found regarding the effects of the variations on ROM.

This was also true in regard to the effects of PNF on athletic performance and muscular strength. Athletic performance was generally found to decrease when PNF stretching was performed before exercise, and increase when performed independent of exercise, or after exercise was completed Marek et al.

Find your nearest clinic » See our clinics on a map. PNF is a form of stretching designed to increase flexibility of muscles and increase range of movement. PNF is a progressive stretch involving muscle contraction and relaxation. Your physiotherapist will gently stretch the muscle and you will resist the stretch by contracting the muscle for about 5 seconds.

Your physiotherapist will indicate the force of contraction required and this depends on the condition of the muscle. You then relax the muscle and your physiotherapist will gently stretch the muscle further for about 30 seconds. There is then about 30 seconds rest and the process is repeated again several times. Above: PNF is an effective technique to imporve muscle length and prevent increased tension.

Renovascular Hypertension — Causes, Symptoms, Treatment. Hypertensive Encephalopathy — Causes, Symptoms, Treatment. Myocardium — Anatomy, Nerve Supply, Functions. At a glance User Review 5 3 votes. PNF Therapy Proprioceptive neuromuscular facilitation is common practice for increasing range of motion, though little research has been done to evaluate theories behind it.

The purpose of this study was to review possible mechanisms, proposed theories, and physiological changes that occur due to proprioceptive neuromuscular facilitation techniques. Four theoretical mechanisms were identified: autogenic inhibition, reciprocal inhibition, stress relaxation, and the gate control theory. The studies suggest that a combination of these four mechanisms enhance the range of motion.

When completed prior to exercise, proprioceptive neuromuscular facilitation decreases performance in maximal effort exercises. When this stretching technique is performed consistently and post-exercise, it increases athletic performance, along with a range of motion. Proprioceptive neuromuscular facilitation PNF stretching techniques are commonly used in the athletic and clinical environments to enhance both active and passive range of motion ROM with a view to optimizing motor performance and rehabilitation.

PNF stretching is positioned in the literature as the most effective stretching technique when the aim is to increase ROM, particularly with respect to short-term changes in ROM. With due consideration of the heterogeneity across the applied PNF stretching research. The muscle group to be stretched is positioned so that the muscles are stretched and under tension. The athlete then contracts the stretched muscle group for 5 — 6 seconds while a partner, or immovable object, applies sufficient resistance to inhibit movement.

The contracted muscle group is then relaxed and a controlled stretch is applied for about 30 seconds, taking the muscle slightly further than it was previously. The muscle group is then allowed 30 seconds to recover and the process is repeated 2 — 4 times. Position the muscle to be stretched in a way that it is full, but passively, stretched and under tension against an immovable object such as the floor, a wall, or with the help of a partner who can hold the limb steady.

Perform an isometric contraction of the target muscle at full stretch. Hold the contraction for at least ten to fifteen seconds. Relax the muscle briefly about three seconds and then move into another full, passive stretch and hold that for about 20 seconds.