Whether improving your flexibility was one of your new year’s resolutions, or you’ve been inspired watching certain tennis stars warming up at the Australian Open, maybe 2025 has you keen to focus on regular stretching.

However, a quick Google search might leave you overwhelmed by all the different stretching techniques. There’s static stretching and dynamic stretching, which can be regarded as the main types of stretching.

But there are also some other potentially lesser known types of stretching, such as PNF stretching. So if you’ve come across PNF stretching and it piques your interest, what do you need to know?

What is PNF stretching?

PNF stretching stands for proprioceptive neuromuscular facilitation. It was developed in the 1940s in the United States by neurologist Herman Kabat and physical therapists Margaret Knott and Dorothy Voss.

PNF stretching was initially designed to help patients with neurological conditions that affect the movement of muscles, such as polio and multiple sclerosis.

By the 1970s, its popularity had seen PNF stretching expand beyond the clinic and into the sporting arena where it was used by athletes and fitness enthusiasts during their warm-up and to improve their flexibility.

Although the specifics have evolved over time, PNF essentially combines static stretching (where a muscle is held in a lengthened position for a short period of time) with isometric muscle contractions (where the muscle produces force without changing length).

PNF stretching is typically performed with the help of a partner.

There are 2 main types

The two most common types of PNF stretching are the “contract-relax” and “contract-relax-agonist-contract” methods.

The contract-relax method involves putting a muscle into a stretched position, followed immediately by an isometric contraction of the same muscle. When the person stops contracting, the muscle is then moved into a deeper stretch before the process is repeated.

For example, to improve your hamstring flexibility, you could lie down and get a partner to lift your leg up just to the point where you begin to feel a stretch in the back of your thigh.

Once this sensation eases, attempt to push your leg back towards the ground as your partner resists the movement. After this, your partner should now be able to lift your leg up slightly higher than before until you feel the same stretching sensation.

This technique was based on the premise that the contracted muscle would fall “electrically silent” following the isometric contraction and therefore not offer its usual level of resistance to further stretching (called “autogenic inhibition”). The contract-relax method attempts to exploit this brief window to create a deeper stretch than would otherwise be possible without the prior muscle contraction.

The contract-relax-agonist-contract method is similar. But after the isometric contraction of the stretched muscle, you perform an additional contraction of the muscle group opposing the muscle being stretched (referred to as the “agonist” muscle), before the muscle is moved into a static stretch once more.

Again, if you’re trying to improve hamstring flexibility, immediately after trying to push your leg towards the ground you would attempt to lift it back towards the ceiling (this bit without partner resistance). You would do this by contracting the muscles on the front of the thigh (the quadriceps, the agonist muscle in this case).

Likewise, after this, your partner should be able to lift your leg up slightly higher than before.

The contract-relax-agonist-contract method is said to take advantage of a phenomenon known as “reciprocal inhibition.” This is where contracting the muscle group opposite that of the muscle being stretched leads to a short period of reduced activation of the stretched muscle, allowing the muscle to stretch further than normal.

What does the evidence say?

Research has shown PNF stretching is associated with improved flexibility.

While it has been suggested that both PNF methods improve flexibility via changes in nervous system function, research suggests they may simply improve our ability to tolerate stretching.

It’s worth noting most of the research on PNF stretching and flexibility has focused on healthy populations. This makes it difficult to provide evidence-based recommendations for people with clinical conditions.

And it may not be the most effective method if you’re looking to improve your flexibility in the long term. A 2018 review found static stretching was better for improving flexibility compared to PNF stretching. But other research has found it could offer greater immediate benefits for flexibility than static stretching.

At present, similar to other types of stretching, research linking PNF stretching to injury prevention and improved athletic performance is relatively inconclusive.

PNF stretching may actually lead to small temporary deficits in performance of strength, power, and speed-based activities if performed immediately beforehand. So it’s probably best done after exercise or as a part of a standalone flexibility session.

How much should you do?

It appears that a single contract-relax or contract-relax-agonist-contract repetition per muscle, performed twice per week, is enough to improve flexibility.

The contraction itself doesn’t need to be hard and forceful – only about 20% of your maximal effort should suffice. The contraction should be held for at least three seconds, while the static stretching component should be maintained until the stretching sensation eases.

So PNF stretching is potentially a more time-efficient way to improve flexibility, compared to, for example, static stretching. In a recent study we found four minutes of static stretching per muscle during a single session is optimal for an immediate improvement in flexibility.

Is PNF stretching the right choice for me?

Providing you have a partner who can help you, PNF stretching could be a good option. It might also provide a faster way to become more flexible for those who are time poor.

However, if you’re about to perform any activities that require strength, power, or speed, it may be wise to limit PNF stretching to afterwards to avoid any potential deficits in performance.

Lewis Ingram, Lecturer in Physiotherapy, University of South Australia and Hunter Bennett, Lecturer in Exercise Science, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

You’ve probably seen recent claims online seed oils are “toxic” and cause inflammation, cancer, diabetes and heart disease. But what does the research say?

Overall, if you’re worried about inflammation, cancer, diabetes and heart disease there are probably more important things to worry about than seed oils.

They may or may not play a role in inflammation (the research picture is mixed). What we do know, however, is that a high-quality diet rich in unprocessed whole foods (fruits, vegetables, nuts, seeds, grains and lean meats) is the number one thing you can to do reduce inflammation and your risk of developing diseases.

Rather than focusing on seed oils specifically, reduce your intake of processed foods more broadly and focus on eating fresh foods. So don’t stress out too much about using a bit of seed oils in your cooking if you are generally focused on all the right things.

What are seed oils?

Seed oils are made from whole seeds, such as sunflower seeds, flax seeds, chia seeds and sesame seeds. These seeds are processed to extract oil.

The most common seed oils found at grocery stores include sesame oil, canola oil, sunflower oil, flaxseed oil, corn oil, grapeseed oil and soybean oil.

Seed oils are generally affordable, easy to find and suitable for many dishes and cuisines as they often have a high smoke point.

However, most people consume seed oils in larger amounts through processed foods such as biscuits, cakes, chips, muesli bars, muffins, dipping sauces, deep-fried foods, salad dressings and margarines.

These processed foods are “discretionary”, meaning they’re OK to have occasionally. But they are not considered necessary for a healthy diet, nor recommended in our national dietary guidelines, the Australian Guide for Healthy Eating.

I’ve heard people say seed oils ‘promote inflammation’. Is that true?

There are two essential types of omega fatty acids: omega-3 and omega-6. These are crucial for bodily functions, and we must get them through our diet since our bodies cannot produce them.

While all oils contain varying levels of fatty acids, some argue an excessive intake of a specific omega-6 fatty acid in seed oils called “linoleic acid” may contribute to inflammation in the body.

There is some evidence linoleic acid can be converted to arachidonic acid in the body and this may play a role in inflammation. However, other research doesn’t support the idea reducing dietary linoleic acid affects the amount of arachidonic acid in your body. The research picture is not clear cut.

But if you’re keen to reduce inflammation, the best thing you can do is aim for a healthy diet that is:

• high in antioxidants (found in fruits and vegetables)
• high in “healthy”, unsaturated fatty acids (found in fatty fish, some nuts and olive oil, for example)

• high in fibre (found in carrots, cauliflower, broccoli and leafy greens) and prebiotics (found in onions, leeks, asparagus, garlic and legumes)

• low in processed foods.

If reducing inflammation is your goal, it’s probably more meaningful to focus on these basics than on occasional use of seed oils.

What about seed oils and heart disease, cancer or diabetes risk?

Some popular arguments against seed oils come from data from single studies on this topic. Often these are observational studies where researchers do not make changes to people’s diet or lifestyle.

To get a clearer picture, we should look at meta-analyses, where scientists combine all the data available on a topic. This helps us get a better overall view of what’s going on.

A 2022 meta-analysis of randomised controlled trials investigated the relationship between supplementation with omega-6 fatty acid (often found in seed oils) and cardiovascular disease risk (meaning disease relating to the heart and blood vessels).

The researchers found omega-6 intake did not affect the risk for cardiovascular disease or death but that further research is needed for firm conclusions. Similar findings were observed in a 2019 review on this topic.

The World Health Organization published a review and meta-analysis in 2022 of observational studies (considered lower quality evidence compared to randomised controlled trials) on this topic.

They looked at omega-6 intake and risk of death, cardiovascular disease, breast cancer, mental health conditions and type 2 diabetes. The findings show both advantages and disadvantages of consuming omega-6.

The findings reported that, overall, higher intakes of omega-6 were associated with a 9% reduced risk of dying (data from nine studies) but a 31% increased risk of postmenopausal breast cancer (data from six studies).

One of the key findings from this review was about the ratio of omega-3 fatty acids to omega-6 fatty acids. A higher omega 6:3 ratio was associated with a greater risk of cognitive decline and ulcerative colitis (an inflammatory bowel condition).

A higher omega 3:6 ratio was linked to a 26% reduced risk of depression. These mixed outcomes may be a cause of confusion among health-conscious consumers about the health impact of seed oils.

Overall, the evidence suggests that a high intake of omega-6 fatty acids from seed oils is unlikely to increase your risk of death and disease.

However, more high-quality intervention research is needed.

The importance of increasing your omega-3 fatty acids

On top of the mixed outcomes, there is clear evidence increasing the intake of omega-3 fatty acids (often found in foods such as fatty fish and walnuts) is beneficial for health.

While some seed oils contain small amounts of omega-3s, they are not typically considered rich sources.

Flaxseed oil is an exception and is one of the few seed oils that is notably high in alpha-linolenic acid (sometimes shortened to ALA), an omega-3 fatty acid.

If you are looking to increase your omega-3 intake, it’s better to focus on other sources such as fatty fish (salmon, mackerel, sardines), chia seeds, hemp seeds, walnuts, and algae-based supplements. These foods are known for their higher omega-3 content compared to seed oils.

The bottom line

At the end of the day, it’s probably OK to include small quantities of seed oils in your diet, as long as you are mostly focused on eating fresh, unprocessed foods.

The best way to reduce your risk of inflammation, heart disease, cancer or diabetes is not to focus so much on seed oils but rather on doing your best to follow the Australian Guide for Healthy Eating.

Lauren Ball, Professor of Community Health and Wellbeing, The University of Queensland and Emily Burch, Lecturer, Southern Cross University

This article is republished from The Conversation under a Creative Commons license. Read the original article.