NZ physiotherapist explains why slouching isn't that bad - and why 'sitting up straight' can be

The importance of 'good posture' has been drilled into many of us since childhood: sit up straight, tuck your hips, and keep your head in line with your body. But according to a Kiwi physiotherapist, all that talk about posture is just that: posturing.

Peter O'Sullivan, a Palmerston North-born Professor of Musculoskeletal Physiotherapy at Perth's Curtin University, argues that holding ourselves ramrod straight isn't doing us any favours when it comes to back pain, despite what we may have been told. 

Two decades ago, O'Sullivan injured his back while skiing, leaving him with debilitating pain. In the years after, the physiotherapist did his best to keep his back as straight as possible, believing poor posture or slouching would only exacerbate his discomfort. 

"The penny dropped one day when a colleague of mine said, 'Why are you holding yourself so tense?'" O'Sullivan told The Project NZ on Wednesday. 

"I looked in the mirror and realised I was holding these really tense, rigid postures. Then, over time, I slowly learned to relax, unravel and use my body normally again - and the pain gradually subsided."

There is a common belief that 'good' posture is important to protect the spine from damage, as well as prevent and treat back pain. Good posture is commonly defined as sitting "upright", standing "tall and aligned", and lifting with a squat technique and "straight back".

While a variety of postures are normal depending on several factors, O'Sullivan noted that "sitting upright and tense" is actually more common in people who suffer with pain - and overall, there's no 'gold standard' of posture. 

"If you look at the history of posture, it comes into this social acceptability of how you should look: this idea of a 'plumbline' where your head sits over your shoulders and through your pelvis. This idea kind of got morphed into not only does this 'look good', but this is good for your spine health," he said.

"Watch people in paddyfields - no one's lifting with a straight back, they're all bending over. We created this whole belief system in more western societies that lifting 'with a straight back' [is safer]. In actual fact it's quite hard work and inefficient to lift with a straight back.

"We have a general belief that our backs are fragile and actually, they're incredibly strong. What we do know about back health though, is you need to use it. Are you engaged in regular physical activity? Are you getting enough sleep? How are you managing your stress? Those things are more predictive of back pain than what your posture is."

Despite evidence that backs O'Sullivan's stance, not everyone is ready to support the idea we should turn our backs on straight spines. 

"Clinicians are still telling people, 'Be careful with your back, you've gotta sit up straight'. We have a whole ergonomic industry that's promoting this: ergonomic chairs, ergonomic beds."  

This sentiment echoes that of Kieran O'Sullivan, senior lecturer at the University of Limerick and lead physiotherapist at the sports spine centre in Aspetar hospital, Qatar, who suggested to The Guardian in 2018 that it might be time to question ergonomic programmes that reinforce 'sitting up straight' is 'good' for back pain.

"These usually involve looking at the chair, height of monitor and where the keyboard and mouse are with the idea that if everything is aligned in a certain way - usually straight - you will get less neck and back pain," he said.

"While it is appealing to think that if you sit up straight you will not get back pain, this is not supported by big studies across many countries.

"If you don't have back pain, then do not give your posture one second's thought - think about being healthy. Sleep deprivation and stress are more important than the lifting you do. Stress has a strong inflammatory role; it can make muscles tense. Most people don't get that their back can become sore if they are sleep deprived."

He, however, disagreed with the other O'Sullivan, and argued that if you already have back pain, poor posture can exacerbate it. Instead, seek advice from a professional about how to avoid worsening existing pain and mitigate the risk of stressing your back further, he advised. 

"After someone has back pain, I would suggest they go to get a bit of advice from a qualified person about how they can move with more confidence and less pain. It is trial and error, but would involve exploring which way of bending is the most comfortable."

A 2012 study of 295 physiotherapists in four European countries asked them to pick their perfect posture from pictures of nine options, ranging from slumped to upright. While 85 percent chose one of two postures, these were very different: one had less lumbar curve than the others and a more erect upper back. The researchers warned this posture in particular actually requires higher levels of muscle activity and could cause greater fatigue and discomfort. 

"Overall, disagreement remains on what constitutes a neutral spine posture, and what is the best sitting posture. Qualitative comments indicated that sitting postures which matched the natural shape of the spine, and appeared comfortable and/or relaxed without excessive muscle tone were often deemed advantageous," the researchers found.

Watch Professor Peter O'Sullivan on The Project above.