Exploring Proprioceptive Neuromuscular Facilitation (PNF): Lower Extremity 

Proprioceptive Neuromuscular Facilitation, which is a specialized stretching technique used in physical therapy and rehabilitation to improve flexibility and range of motion (ROM). It plays a vital role in reducing spasticity of muscle for example the Hold Relax technique. It promotes muscle relaxation.

Indications of Proprioceptive Neuromuscular Facilitation

Musculoskeletal Injuries

Musculoskeletal conditions like muscle sprain, ligament injuries and muscle spasm can be treated with PNF stretching techniques. Musculoskeletal problems can hinder the normal biomechanics of gait. Hamstring tightness is a common problem. An autogenic inhibition phenomenon leads to muscle relaxation and reduced resistance during stretch. Soft tissue mobilization can also be incorporated with PNF for better results. Hold relax technique can be used.

Post-surgery Rehabilitation

Post-surgery rehabilitation plays an important role in reducing muscle atrophy and restoring normal movement pattern. Anterior cruciate ligament injuries are a common example in athletes. Physiotherapy is beneficial for ensuring good quality of life. Stretching Technique is effective for anterior cruciate ligament reconstruction along with post isometric relaxation.

Neurological Disorder

Neurological disorders like stroke can be treated with PNF techniques for upper and lower extremity. Proprioceptive neuromuscular facilitation-based gait training along with routine physical therapy is more effective in improving balance thus reducing chances of falling. Spinal cord injury and Parkinson are also some examples in which PNF can be used.

Chronic Pain Management

PNF can be useful in treating chronic back pain and posture correction which can be a major cause for limb asymmetry. Proprioceptive neuromuscular facilitation trunk pattern exercises in sitting position improve muscle endurance and flexibility. The PNF lower extremity pattern training affects the activation of the core positively. Dynamic patterns of PNF are suggested to improve lumbar posture effectively.

Pediatric Rehabilitation

PNF technique can be used in pediatric population to treat conditions like cerebral palsy. One of the techniques within PNF is the Hold Relax technique, which involves lengthening the muscles to a specific point where an individual performs an isometric contraction for 10 seconds, followed by passive limb movement to a new range of motion.

 

Indications of Proprioceptive Neuromuscular Facilitation

• Increased flexibility
• Improved ROM
• Muscle strength
• Injury prevention
• Decrease muscle soreness
• Promote blood circulation
• Alleviate muscle spasm

 

Contra-indication of Proprioceptive Neuromuscular Facilitation

• Recent surgery
• Osteoporosis
• Joint instability
• Inflammation or swelling
• Nerve injury
• Fracture

 

Principle

The primary idea behind PNF is to draw in the neuromuscular reflexes that work with muscle unwinding, considering a more noteworthy stretch without setting off the stretch reflex, which could make the muscle contract in light of the stretch.

Hold-Relax (Contract-Relax):

In this technique, the patient actively stretches a muscle group until a comfortable limit is reached. The patient then contracts the target muscle isometrically (without moving) against resistance for about 5 to 10 seconds. After the contraction, the patient relaxes, and the therapist stretches the muscle further. This process helps to trigger the autogenic inhibition reflex, which allows for an increased stretch.

Contract-Relax-Antagonist-Contract (CRAC):

This technique builds upon the Hold-Relax method. After the isometric contraction and relaxation of the target muscle, the patient then contracts the opposing muscle (antagonist) while the therapist provides resistance. This reciprocal inhibition helps to further enhance the stretch and range of motion.

 

 

Slow Reversal-Hold-Relax (Slow Reversal PNF):

In this technique, the patient performs alternating concentric (muscle shortening) and eccentric (muscle lengthening) contractions of the target muscle against resistance. After several repetitions, a hold-relax contraction is performed to gain additional stretch.

 

PNF Technique for Lower Extremity

D1 Flexion

• Hip is in extension, abduction and internal rotation
• Ankle plantar flexion
• Foot eversion
• Toes flexion, and internally rotated

 D1 Extension

• Hip is in flexion, adduction and external rotation
• Ankle dorsiflexion
• Foot inversion
• Toes extension

 D2 Flexion

• Hip is in flexion, adduction and internal rotation
• Ankle dorsiflexion
• Foot inversion
• Toes extension

 D2 Extension

• Hip is in flexion, abduction and internal rotation
• Ankle dorsiflexion
• Foot eversion
• Toes extension

How do you perform a PNF technique?

1.  identify the target muscle
2. choose the starting position 
3. create tension in the target muscle by isometric contraction
4. relax the muscle
5. muscle is then further stretched passively by therapist
6. Repeat it few times i.e. 3-5 sets
7. Thera-band can also be used to provide resistance

Example

1. The patient is in supine lying with 90° flexion of the hip.
2. The physiotherapist passively extends the knee joint where the patient was feeling mild stretch.
3. Then physiotherapist asked the patient to do knee flexion in counter-resistance applied by the therapist by using about 50% of his maximum strength and isometric contraction of the hamstring muscles was achieved. 
4. Patient maintained that isometric contraction for 8 s then relaxes on the physiotherapist’s command.
5. Just after relaxation therapist further stretches the hamstring muscle to the point of mild to moderate painless stretch and the patient hold it for 30 s. Three repetitions are applied.