PNF stretching, proprioceptive neuromuscular facilitation, is considered the most effective and fastest way to increase static-passive flexibility. PNF stretching involves the combination of Passive and Isometric stretches.

The 3 most common forms of PNF stretching are the following:
Hold Relax, Hold Relax Contract, and the Hold Relax Swing

Here is an example of a PNF stretch:

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