Proprioceptive Neuromuscular Facilitation

PNF Background

  • Physical Therapy Technique - originally designed for polio patients with paralysis.
    • Enhances neuromuscular function by activating proprioceptors through targeted muscle contractions.

Reflexes Relevant to Facilitated Stretching

  • Myotatic Stretch Reflex - proprioceptors in the muscles (muscle spindles) monitor the length and tension of the muscle. If the muscle lengthens unexpectedly, the muscle spindles are stimulated, causing the muscle to contract.
  • Inverse Stretch Reflex (Autogenic Inhibition) - Golgi tendon organs (GTOs), receptors located in the musculotendinous junction area and tendon, monitor muscle tension. Common belief has been that if the load on the tendon becomes too great, GTOs are stimulated, causing the muscle to relax. Although this inverse stretch reflex is not clear today, experience had shown there is a postisometric effect that allows a muscle to stretch more easily.
  • Reciprocal Inhibition - during contraction of the agonist, inhibition of the antagonist allows movement to occur around the joint.
  • muscle spindle

Soft Tissues Affected by Stretching

  • Connective Tissue - the building block of all soft tissues - composed of collagen and elastic fibers, embedded in a jelly-like matrix that acts as a lubricant. connective tissue
    • Collagen is the most abundant protein in the body, exhibiting excellent tensile strength and relative inextensibility. Like a muscle fiber, collagen fibers are striated and composed of fibrils.
    collagen
  • Fascia - composed of various types of connective tissue - surround and connect every muscle and organ.
  • Ligaments - composed of collagen bundles running parallel with elastic fibers interwoven - connect bone to bone. ligament
  • Tendons - tightly packed bundles of collagen fibers in a wavy configuration (crimp) - connect muscle to bone. tendon
  • Muscle - Layer 1: endomysium wraps muscle fiber -> Layer 2: perimysium wraps bundles of muscle fibers (fascicles) -> Layer 3: epimysium wraps bundles of fascicles. muscle

Chronic Adaptations to Flexibility Training

  • Mechanical effects of stretching are inconclusive - belief used to be that increased ROM that occurs as a result of stretching was due to an increase in the sarcomeres of the muscle fiber.
  • Currently, the sensory theory is the most widely accepted theory - increased ROM is due to an increase in the stretch tolerance of the stretcher.

Stretch vs. Strengthen

  • Hypertonic muscles (need to stretch) - short and tight due to habitual concentric contraction (pec major).
  • Eccentrically stressed muscles (need to strengthen) - overstretched, long and tight, ususally due to postural stress (rhomboids).
  • hypertonic

PNF Stretching Techniques

  • Agonist contraction (reciprocal inhibition) - trainer moves stretcher's limb to point of stretch and then lets target muscle go a little slack. Stretcher contracts opposing agonist to the complete end range and holds for several seconds. The movement to end range is slow and controlled by stretcher, with no passive pressure applied by trainer.
  • Contract-Relax Stretching - ideal for clients who exhibit a marked limitation in ROM. Trainer moves limb to point of stretch and holds for 10 seconds. Stretcher then isotonically contracts the target muscle for 6 seconds (trainer allows slight movement). Then, stretcher relaxes and trainer moves limb to new ROM.
  • Hold-Relax Stretching - ideal for clients who exhibit extreme limitation in ROM. Trainer moves limb to point of stretch and holds for 10 seconds. Stretcher then isometrically contracts the target muscle for 6 seconds (no movement). Then, stretcher relaxes and trainer moves limb to new ROM.
  • Hold-Relax-Agonist-Contract - a combination of the HR and AC techniques. Trainer moves limb to point of stretch and holds for 10 seconds. Stretcher then isometrically contracts the target muscle for 6 seconds (no movement). Then, stretcher contracts opposing agonist to move limb new ROM.

Neck

    neck
  • Supine
    • Upper Trapezius - Guide stretcher's head to right and tuck chin to stretch point. Right hand on shoulder, left hand on occiput. Stretcher isometrically contracts against both hands, trying to move back of the head to left shoulder. After isometric contraction, stretcher relaxes and breathes in. Stretcher then exhales and moves head farther to right, tucks chin and pulls shoulder farther away from head.
    • upper traps
    • Sternocleidomastoid - Have stretcher turn head to the left. Cradle stretcher's head in left hand and place right hand above ear. Stretcher isometrically contracts against right hand by slowly rotating head to the right (not lifting head). After isometric contraction, stretcher relaxes and breathes in. Stretcher then exhales and rotates head farther to left.
    • sternocleidomastoid
    • Scalenes - Have stretcher laterally flex head and neck to the right to stretch point, keeping nose pointed to the ceiling. Stretcher also pulls left shoulder away from head. Place right hand on head, just above ear, and left hand against shoulder. Have stretcher push against right hand only as if trying to move ear to shoulder. After isometric contraction, stretcher relaxes and breathes in. Stretcher then exhales and moves right ear closer to shoulder.
    • scalenes

Additional Muscles That Move The Arm

    lats pectoralis
  • Seated
    • Latissimus Dorsi - Stretcher keeps back and neck lengthened as you move his right arm with elbow bent, up behind his head and reaching toward his left shoulder. Make sure chin doesn't drop to chest. Place your right hand against right elbow and left hand against left shoulder. Stretcher attempts to move right arm down toward right side. After isometric contraction, stretcher reaches right arm farther to the left.
    • lats
    • Pectoralis - Stretcher abducts and externally rotates arms to 90 degrees, with elbows bent to 90 degrees. Stretcher then actively pulls shoulder blades together to horizontally abduct arms, lengthening pecs to pain-free end range. Stand behind stretcher with hands supporting elbows in supine grip. Have stretcher press against hands, trying to pull arms toward chest.
    • pectoralis

Low Back Stretch

    low back
  • Supine
    • Both Knees to Chest - Stretcher actively pulls knees to chest. Place both hands behind knees and add passive stretch to stretch point. Stretcher pushes against you as if trying to straighten legs. After isometric contraction, stretcher relaxes while you add additional passive stretch.
    • low back

Hamstring Stretch

    hamstrings
  • Supine
    • Straight Leg - Stretcher raises right leg as high as possible, keeping knee straight. Hips remain flat on surface. Tell stretcher to allow knee to lock and push against you as if trying to put heel on the table. After 6 seconds of isometric contraction, stretcher relaxes and inhales deeply. On exhale, stretcher contracts hip flexors to left leg higher.
    • hamstrings

Gluteus Maximus Stretch

    gluteus maximus
  • Supine
    • Stretcher lifts knee to chest. Place right hand behind the knee, left hand on shin, just below the knee. Stretcher pushes against right hand, attempting to lower leg toward table or mat.
    • gluteus maximus

Piriformis Stretch

    piriformis
  • Supine
    • Stretcher flexes hip and knee to 90 degrees. Move foot toward opposite shoulder so thigh rotates laterally. Hand on lateral knee and ankle. Stretcher pushes leg diagnally with equal pressure on knee and ankle.
    • piriformis

Adductor Stretch

    adductors
  • Supine
    • Stretcher abducts hip to stretch range, knee facing up and other heel over end of table. With hand on medial aspect of knee and other hand supporting ankle, have stretcher try to close leg.
    • adductor stretch