Proprioceptive Neuromuscular Facilitation (PNF stretching) is a different approach to stretching that involves both stretching and contracting the targeted muscle group. This form of assisted stretching developed as a rehabilitative therapy for paralysis or stroke and then found its way into the athletic world.
First, you passively stretch a specific muscle, then contract the muscle isometrically against resistance while holding the muscle in the stretch, and then you passively stretch again with an increased range of motion. Skip to video.
The basic process of doing a PNF stretch goes like this:
Move the targeted muscle into a position where you feel a slight stretch.
With the help of a partner, or using an immovable object, as resistance to inhibit movement, gently contract the stretched muscle for 5 to 10 seconds.
Relax for 2 to 3 seconds. Do a passive stretch for 10 to 30 seconds. (Exact timing recommendations vary, depending on who you ask.)
Rest for 30 seconds.
Repeat the process 2 to 4 times.
Note: Before any stretching, warm up to increase your body's core temperature and muscle temperature, preparing your body for more strenuous activity. More about warming up.