PNF Stretching techniques can maximize improvements in flexibility. PNF stretching works by developing muscular relaxation and allowing a greater range of movement during the stretching session.
Proprioceptive Neuromuscular Facilitation (PNF) Stretching techniques are more effective than simple passive stretching. The success is explained by the effect of PNF stretching on the proprioceptors within the muscle and tendon. One of these proprioceptors, the Golgi Tendon Orgran (GTO) is sensitive to increasing tension within a muscle. When stimulated, the GTO causes muscular relaxation. If this relaxation occurs in the same muscle experiencing the increased tension, the result is called autogenic inhibition.
If relaxation occurs in the muscle opposing the muscle experiencing the increased tension, the result is called reciprocal inhibition. During a passive stretch, reciprocal inhibition can be utilised by simultaneously contracting the muscle opposing the muscle being stretched. Then tension in the contracting muscle stimulates the GTO and causes a simultaneous reflex relaxation in the opposite muscle.