Lifting technique, Ergonomics & Low Back Pain: Much Ado about Nothing?

 In Lower Limb

Low back pain is the leading cause of disability worldwide and is the most common complaint I see in my work as a Physiotherapist (1). Despite decades of research and various interventions, low back pain chronicity and disability has been on the increase (2). This is particularly true when it comes to workplace-related low back pain, with the resulting disability having enormous consequences in terms of distress and economic costs of absence from work and reduced productivity (3). Whilst it has been shown that heavy lifting at work increases the risk of low back pain, the efficacy of common workplace education and training interventions to prevent low back pain have been called into question (3).

Lifting is commonly cited as being provocative in those with low back pain (6). Thus, manual handling training and equipment often focuses on lifting to try to minimise the risk of low back pain (3,4, 6). This typically involves advice to lift loads close to the body whilst keeping the back straight and knees bent (as seen in the image below) (3, 6).

 

   

 

This lifting advice originates from early in vitro (“in glass” / removed from the body) modelling of cadaveric spinal intervertebral discs showing herniation following low-load repetitive flexion and extension moments (6).

Subsequent in vivo (“within the living”) studies reported increased intradiscal pressures during lifting with a round back when compared to straight-back lifting (6). This view of lumbar disc vulnerability to lifting has been widely accepted the majority of Physiotherapists and Ergonomic/Manual handling educators worldwide (6). With the central belief being that straight back lifting is safer than lifting with a rounder back (6). Training in correct working techniques and lifting equipment is still widely used across the developed world to manage the increased risk of back pain related to repeated heavy lifting and handling (3).

It is intuitive to think that heavy lifting on its own, is a principal causal factor in developing low back pain at work. Workers remain as exposed to manual heavy lifting in the workplace as they did 20 years ago: 33% of workers carry heavy loads at least a quarter of their working time (4). It is not surprising that emphasis has been given to optimise lifting techniques to prevent low back pain (4)

However, the associations between heavy manual work and low back pain are conflicting (6). While there are studies that show modest associations in between the two, there are also studies showing that a reduction in the physical nature of work did not reduce the incidence of low back pain (6). Recent research calls into question common lifting and ergonomic interventions their supposed preventative effect on workplace-related low back pain (3,4,5,6).

Nurses are one profession in particular have been subject to a great degree of research in this area, with nursing been identified amongst the top professions at risk of low back pain, and low back pain rates exceeding those employed in heavy industry (5). The year prevalence of low back pain in nurses has a mean of 70% (5). In nursing there is a strong belief that isolated “no-lift” policies are the most important aspect in the prevention and treatment of low back pain in the work environment (5). However, a recent systematic review showed that there is no consistent evidence to support the use of “no-lift” policies and strong focus on “correct” lifting technique (5). The authors of the review highlighted the importance of focusing more on sustained and repetitive non-lifting manual nursing tasks (e.g. bending and sitting) and cumulative stress-related low back pain in the prevention and treatment of low back pain among nurses (5).  

But what about everyone else?

Three reviews on workplace lifting advice and assistive equipment from 2008, 2012, 2013 all report that there is no evidence to support that training with or without lifting equipment is effective in the prevention of back pain or consequent disability.

In fact a recent review from 2019 looked into the differences in lifting technique between those with and without low back pain (6). They found that people with LBP move slower, stiffer, and with a deeper knee bend than pain-free people during freestyle lifting tasks (1). Meaning that those WITH low back pain tend to lift in the way we have all been advised (see image 1 above), whereas those WITHOUT low back pain tend to lift in a more relaxed stooped fashion (as seen in picture 2 below).  

 

Now why would people with low back pain move differently? The authors of the previously mentioned review suggest that there are three possible reasons:

  1. They move differently to protect the spine from excessive loading
  2. They move like this as part of a protective pain behaviour
  3. There is a cultural acceptance that lifting “squat” style lifting is safest

Personally, I feel the reason those with low back pain move differently is a combination of all three. As we have seen, ‘ideal’ lifting techniques are not helpful in preventing low back pain, and so it is most likely that those with low back pain lift in a squatter dominant pattern (“straight back, using the legs” etc..) as a protective pattern for a overloaded lower back.

Low back pain is best understood as a result of an imbalance between our capacity to load and our physical loading. In patients with low back pain (and any other pain for that matter) our capacity to load arises from the following:

  • Physical (posture- and movement behaviour, loading exposures)
  • Neurophysiological (neuro-immune system, stress)
  • Psychological (cognitions, emotions and stress)
  • Social (socioeconomic, cultural, work, home environment)
  • Lifestyle (sleep, activity levels)
  • Non-modifiable (genetics, patho-anatomical, sex, life stage)

In each individual there is variable, fluctuating and unique interaction between all these different factors that lead to either increased or reduced overall capacity (5). When the overall loading we put on our bodies (physical, psychological etc) exceeds our current capacity, I often find that we are more likely to experience pain and injury.  

So what do we make of all this?

Firstly, long held cultural notions of ideal lifting technique and the need for assistive devices to prevent lower back pain are not supported by the current research evidence.

Secondly, this re-affirms the notion that our backs are likely more resilient and capable than we give them credit for.

And finally, it points towards the bigger, more complex picture of how low back pain may arise and can be treated – as a balance of a wide range of biopsychosocial factors that enhance or diminish our capacity to tolerate physical load/stress.  

 

Oliver

Oliver Crossley (APAM)
POGO Physiotherapist

Book an appointment with Oliver here

Featured in the Top 50 Physical Therapy Blog  

References:

  1. O’Sullivan, Peter, Joao Paulo Caneiro, Mary O’Keeffe, and Kieran O’Sullivan. “Unraveling the complexity of low back pain.” Journal of orthopaedic & sports physical therapy46, no. 11 (2016): 932-937
  2. Traeger, Adrian, Rachelle Buchbinder, Ian Harris, and Chris Maher. “Diagnosis and management of low-back pain in primary care.” Cmaj189, no. 45 (2017): E1386-E1395
  3. Martimo, Kari-Pekka, Jos Verbeek, Jaro Karppinen, Andrea D. Furlan, Esa-Pekka Takala, P. Paul FM Kuijer, Merja Jauhiainen, and Eira Viikari-Juntura. “Effect of training and lifting equipment for preventing back pain in lifting and handling: systematic review.” Bmj336, no. 7641 (2008): 429-431
  4. Verbeek, Jos H., Kari-Pekka Martimo, P. P. F. M. Kuijer, Jaro Karppinen, Eira Viikari-Juntura, and Esa-Pekka Takala. “Proper manual handling techniques to prevent low back pain, a Cochrane systematic review.” Work41, no. Supplement 1 (2012): 2299-2301
  5. Van Hoof, Wannes, Kieran O’Sullivan, Mary O’Keeffe, Sabine Verschueren, Peter O’Sullivan, and Wim Dankaerts. “The efficacy of interventions for low back pain in nurses: a systematic review.” International journal of nursing studies77 (2018): 222-231
  6. Nolan, David, Kieran O’Sullivan, Chris Newton, Gurpreet Singh, and Benjamin E. Smith. “Are there differences in lifting technique between those with and without low back pain? A systematic review.” Scandinavian journal of pain(2019)
  7. Driessen, Maurice T., Karin I. Proper, Maurits W. van Tulder, Johannes R. Anema, Paulien M. Bongers, and Allard J. van der Beek. “The effectiveness of physical and organisational ergonomic interventions on low back pain and neck pain: a systematic review.” Occupational and environmental medicine67, no. 4 (2010): 277-285

     

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