PNF (proprioceptive neuromuscular facilitation) hold-relax is intended to stretch / increase length of a muscle and musculotendinous unit. Technique: A 5-second isometric contraction of the target or antagonist muscle is followed by a 10 second static stretch of the same muscle. Alternating between isometric contractions and stretch is typically performed 3-4 times. PNF Hold-relax stretching techniques are shown to be effective for increasing muscle length but the underlying mechanisms are unclear and research findings are mixed. This video briefly discusses the neurophysiological and viscoelastic mechanisms believed to be associated with PNF hold-relax techniques.
