Proprioceptive Neuromuscular Facilitation (PNF) is a type of stretching developed by Dr. Herman Kabat in the early 1940s. One of the common ways to perform PNF stretching is to place a muscle under stretch, contract the muscle for approximately six seconds against a sturdy object (or the resistance of a trainer) and then relax.
What PNF does is create a response in the proprioceptors in the muscle that causes the muscle to relax, often to a greater degree than is possible with static stretching. However, a study published in the March 2011 issue of the Journal of Strength and Conditioning Research found that when performed before strength training, PNF stretching decreased muscular endurance (using between 40 and 80 percent of the 1-repetition maximum) in the bench press and in knee extension exercises. The study also showed that static stretching also decreased performance in these two exercises, although not as much as PNF stretching did, but more so than a control group that did no pre-workout stretching.
Copyright ©2011 Charles Poliquin