The patterns of movement associated with PNF are composed of multijoint, multiplanar, diagonal, and rotational movements of the extremities, trunk & neck. There are 2 pairs of foundational movements for the upper extremities; UE D1 flexion & extension, UE D2 flexion & extension. There are also 2 pairs of foundational movements for the lower extremities; LE D1 flexion & extension, LE D2 flexion & extension. Various PNF stretching techniques based on Kabat’s concept are: Hold Relax, Contract Relax, and Contract Relax Antagonist Contract (CRAC) etc.
Contract Relax: Passive placement of the restricted muscle into a position of stretch followed by an isotonic contraction of the restricted muscle. Most isometric contractions in PNF stretching techniques should be held for a minimum of 3 seconds at a sub maximal effort (20-50% of maximal effort) to avoid muscle fatigue and injury. After the contraction period the subject is instructed to relax the restricted muscle that was just contracting and activate the opposing muscle to move the limb into a greater position of stretch. Through Golgi tendon organ, the tight muscle is relaxed, and allowed to lengthen.
Hold Relax: Very similar to the Contract Relax technique. This is utilized when the agonist is too weak to activate properly. The subjects restricted muscle is put in a position of stretch followed by an isometric contraction of the restricted muscle. After the allotted time the restricted muscle is passively moved to a position of greater stretch. Contraction times and efforts will remain the same as the Contract Relax technique. This technique utilizes the autogenic inhibition, which relaxes a muscle after a sustained contraction has been applied to it for longer than 6 seconds
