Flexibility is key for athletes and nonathletes alike. It allows you to move freely and comfortably in your daily life, and can also help prevent injury during exercise. One of the best ways to increase your flexibility is by stretching. However, research suggests that not all stretching techniques are created equal. Proprioceptive neuromuscular facilitation (PNF) stretching relies on reflexes to produce deeper stretches that increase flexibility.
According to the International PNF Association, PNF stretching was developed by Dr. Herman Kabat in the 1940s as a means to treat neuromuscular conditions including polio and multiple sclerosis. PNF techniques have since gained popularity with physical therapists and other fitness professionals. It’s easy to understand why. According to research from the University of Queensland, PNF stretching may be the most effective stretching technique for increasing range of motion.
While there are multiple PNF stretching techniques, all of them rely on stretching a muscle to its limit. Doing this triggers the inverse myotatic reflex, a protective reflex that calms the muscle to prevent injury.
“PNF causes the brain to go ‘I don’t want that muscle to tear’ and sends a message to let the muscle relax a little more than it would normally,” says fasciologist Ashley Black.
One PNF technique that Black says can trigger the reflex is commonly called “hold-relax.” This involves:
- Putting a muscle in a stretched position (also called a passive stretch) and holding for a few seconds.
- Contracting the muscle without moving (also called isometric), such as pushing gently against the stretch without actually moving. This is when the reflex is triggered and there is a “6- to 10-second window of opportunity for a beyond ‘normal’ stretch,” Black says.
- Relaxing the stretch, and then stretching again while exhaling. This second stretch should be deeper than the first.
Another common PNF technique is the contract-relax stretch. It is almost identical to hold-relax, except that instead of contracting the muscle without moving, the muscle is contracted while moving. This is sometimes called isotonic stretching.
For example, in a hamstring stretch, this could mean a trainer provides resistance as an athlete contracts the muscle and pushes the leg down to the floor.
A third technique, hold-relax-contract, is similar to hold-relax, except that after pushing against the stretch, instead of relaxing into a passive stretch, the athlete actively pushes into the stretch.
For example, in a hamstring stretch, this could mean engaging the muscles to raise the leg further, as the trainer pushes in the same direction.
Regardless of technique, PNF stretching can be used on most muscles in the body, according to Black. Stretches can also be modified so you can do them alone or with a partner.
If you want to increase your range of motion in a particular area because of an injury, consult a physical therapist trained in PNF stretching. To improve your general flexibility, Black recommends targeting the “long kinetic chains” in the body. These include the:
- side fascia
- hip flexors
“If an individual can open these, then they can have a real impact on their mobility,” she says.
Black offers several tips to help you figure out whether you’re using PNF stretching correctly.
- “Every time you exhale and deepen the stretch, you should see a noticeable change in range of motion, from 10 to 45 degrees,” she says.
- Black recommends breathing through stretches and using calming thoughts to avoid tightening up during the stretch.
- Finally, when using PNF, “Keep it simple and just remember: contract, relax, breathe, and stretch,” Black says. “The nervous system and reflexes will do the rest.”
If you are not familiar with this type of stretching, seek out a professional or trainer to make sure you are doing the move correctly. If you are under 18, PNF stretching is generally not recommended. Always seek the advice of a doctor or fitness professional before trying it.
By working with your natural reflexes, PNF stretching is an easy and effective way to increase your overall flexibility and range of motion.