Proprioceptive neuromuscular facilitation (PNF) stretching is a more advanced technique that involves both stretching and contracting the targeted muscle group. Typically, this is done with the help of your therapist. One common PNF stretch is the contract-relax method, where you stretch a muscle, contract it against resistance for a few seconds, and then stretch it further. This method can lead to significant improvements in ROM by taking advantage of the natural reflexes of the muscles.