Sitting hurts your loins, staring, your eyes
Plautus, c. 225BCE
Posture is the arrangement of the human body, being the trunk and the limbs. The human body is always in some kind of posture, whether a person is walking, sitting, standing, lying down, driving, sporting, lifting, carrying, or any combination of the above - the body is always engaged, so the body is always in posture. Maintaining, moving through, and modifying postures is done by the action of the muscles, which work even when the body is standing still (Caneiro et. al., 2010). Every movement is a posture, every posture is a movement. Contemporarily, posture is discussed with reference to the trunk, specifically the arrangement of the head, the shoulders, the chest and abdomen, and the curves of the spine in sitting and standing. Attention is paid to make sure that people assume good, or correct postures throughout the day to minimise the risk of injury, to improve overall health, and to improve personal comfort. Postures vary greatly between individuals because individual anatomies are different (Barrett et. al., 2016). Current literature suggests that the concept of incorrect or misaligned postures is more subjective than otherwise (Slater et. al., 2019). In spite of this, attention is paid to postures that are assumed during actions like lifting and carrying, or when relaxing and sitting down. All human activity requires the use of the human body, and so the human body will always be in a posture regardless of what it is doing, in a broader ecosystem of contributory, mitigating, and magnifying elements (Haslegrave, 1994). Human postural control fluctuates with time of day (Gribble & Tucker, 2007; Halpern et. al., 2022), and with fatigue (Bougard et. al., 2011). Control of posture can be affected by age and illness (Earhart, 2013), the activity being performed and the challenge it imposes on the body (Papegaaij et. al., 2016), and with alertness (Fabbri et. al., 2006).
If good posture can be described as anything, it can be described as a human body’s ability to meet the demands of a task, and is best considered as just one activity among many (Smythe & Jivanjee, 2021). Maintaining posture requires balance, strength, coordination, endurance, flexibility, awareness, fatigue, muscular power, and appropriate body composition. There is no such thing as an ideal human posture. There is no perfect way to sit, stand, walk, change a tire, cut food, use a keyboard, or carry groceries. Rather, there are ways of doing things which put more or less strain on the anatomies and functional capabilities of people, who are all individual, which may be examined to best protect them against excessive or accumulated load (Vieira & Kumar, 2004). Taken this way, postural pain may be evaluated under the broad heading of body-stressing (Comcare, n.d.) wherein while the accumulation of stress is slow and occurs over a long timeframe, the net result still conforms to the clinical pattern of aggravation and symptomatology. Given this, postural complaints and work related injuries may experience the same pattern of under-reporting, where posture is not a linear contributing factor to the incidence of a problem but a contextual one. Thus, posture and body arrangements are best considered antecedents which, if not addressed, makes a worker more vulnerable to hazards in an acute sense as well as the accumulative effect of chronic exposure.
Pain and injury arises from stress that is applied to the body in such a way that they cause pain (Zernicke & Whiting, 2000), the experience of which may be magnified by social, psychological, individual and situational stressors (Chapman et. al., 2008). Every activity exposes the human body to physical and postural stress due to load, which can be external in the case of work which requires lifting and carrying, or internal where the body must carry and manage its own weight (Kumar, 2001). The human body is largely able to adapt to the strain to which it is imposed. However, the average adult will spend more than eight hours a day, five days a week, forty-eight weeks out of the year, from anywhere between forty to sixty years in their life working. Even if the worker works a desk job, this is a significant dose of strain. Where the work is physical, like in trades, mechanics, and manufacturing, the body experiences more load, and more strain as a consequence of more intense and varied use. Suboptimal posture can contribute to injuries that arise slowly where the gradual repeated use of the body gives rise to physical changes that predispose a person to discomfort (Stock, 1991). Suboptimal postures can contribute to injuries that arise quickly where, due to poor management of load such as during lifting and carrying, due to poor management of the body in such activities as turning and twisting, or due to poor awareness during tasks, the worker’s body is exposed to physical load that exceeds the mechanical tolerances of their anatomy, giving rise to injury. Before continuing, it is also worth evaluating occupational postural risk in the ecosystem of human activity. An office worker may sit at their desk for an extended period of time, but may also sit during their commute. In 2021, 53.1% of Australians commuted to work by car (Australian Bureau of Statistics, 2022). Driving a car requires a seated posture. Riding a train or a tram lets people sit down. In 2022, 46.9% of employed adults aged 18-64 years described their day at work as mostly sitting (ABS, 2023). The Australian Institute of Health and Welfare (AIHW) notes that, despite the decrease in the proportion of adults aged 18 and over who did not meet physical health guidelines, in 2022, 80% of adolescents, 73% of adults aged 18-64, and 84% of adults aged 65 and over did not do enough muscle-strengthening activities, and that these trends were more prominently observed in lower socioeconomic areas than in higher ones (AIHW, 2024; ABS 2023). The effect is reversible too, where changes in lower back curvature have been found to be positively correlated with incidence of hamstring injury in athletes (Hennessey & Watson, 1993). At work and in homes the worker is exposed to ecosystems of strain and stress whose effect is not mitigated, and compounds, which may magnify the effect of poor or passive postures at work.
The challenge of improving physical health by reducing sedentarism due to prolonged posture, and protecting health during dynamic posture, is that work tasks and packages are reduced to their simplest, most easily repeatable and standardised forms in order to maximise their efficiency. This makes them either sedentary, repetitive, or sustained. People sit at desks and workstations because information is best organised in one place and generally best engaged with while people are sitting still (Baker et. al., 2019; Podrekar et. al., 2020). While cars and engine cores can be raised, lowered, rotated, tilted and turned with stands and cranes, these movements are done to standardise the work so as to make it stereotypically accessible. Sustained sitting is significantly associated with increased risk of chronic lower back pain in examined samples (Bontrup et. al., 2019; Hanna et. al, 2019). Before thinking about suboptimal postures, activities that are sustained as a consequence of their task constitution and their place within a broader ecosystem of work can increase or decrease the likelihood of irritation or injury. If posture is how an activity is done, doesn’t it miss the boat to not consider the activity to minimise sustained body arrangement first? Workers will already attempt to minimise the extent to which they need to maintain static or low-amplitude postures, as have been seen in populations with chronic low back pain (Popa et. al., 2007). Safe Work Australia guidance encourages movement at least every thirty minutes and to minimise time spent in sedentary postures to a maximum of seven hours a day (Safe Work Australia, n.d.). However, is it really practical for workers to change their posture or move around every thirty minutes? The solution to this would be to use standing desks, which do show some promise in minimising lower back pain (Ognibene et. al., 2016; Barbieri et. al., 2020) but while prolonged standing has less of an effect on lower back pain (De Carvalho et. al., 2020), and participants may benefit from structured guidance (Nelson-Wong et. al., 2020) the true clinical effect may be down to the number of sit-stand-cycles a worker completes during a working period rather than merely replacing sitting time with standing time. If that’s the case, then why not just prescribe squats for workers, where physical exercise in the workplace may very well be a silver bullet (Gobbo et. al., 2019; Johnston et. al., 2019), given the established effectiveness of exercise-based programs in the ecosystem of work-enabling interventions (Van Poppel et. al., 2004; Williams et. al., 2007). This hasn’t touched on the activity load of repetitive movements, high-force movements, and awkward movements, all of which impose novel and notable loads on the body which need to be mitigated. These have been examined previously, and will be examined in further detail elsewhere.
The effect of prolonged sedentary, repetitive, or sustained postures is observable in broader physical, anatomical, and histological changes. These changes are observable in a person’s general health as well as their presentation of musculoskeletal problems like lower back pain as well (Goyal & Rakhra, 2024). Patients with lower back pain present with conversion of slow-twitch Type I muscle fibers to Type II fibers as well as altered pattern of muscle recruitment when compared with a population of patients without back pain (Demoulin et. al., 2007). These changes are believed to occur as a consequence of muscular and structural adaptation to the loads to which the body is or is not exposed (Mannion, 1999). Muscles, bones, and all human tissue need a balanced exposure to load for their best cellular and functional health. If a muscle or structure receives too little stimulation it becomes wasted and atrophied. Too much stimulation or load in one go and the adaptive properties of that muscle are exceeded with consequences that are catastrophic. Dosed resistance in the form of physical exercise, conditioning, and engagement are needed to keep muscles working well and functional, and to preserve the adaptational and functional capacities which precede human health (Sandler, 2012). However, it is possible for the body to be engaged to an extent that it begins adapting adversely due to adverse environmental contributing factors and harmful synergies of forces (Magnusson et. al., 1998; Jaffar et. al., 2011). Patients with shoulder over-use injuries present with forward head posture and forward scapular rotation - the shoulders are tilted forward, the head is tilted forward, and the arms are swung upward, forward, and inward (Greenfield et. al., 1995). These postural parafunctional adaptations are stereotypical of sustained keyboard use combined with inappropriate workstation setup compounded by insufficient breaks - a stereotypical constellation of predisposing factors that is easily amenable to intervention with good work design and a little physical therapy (Bleecker et. al., 2011). With respect to the neck, shoulders, and upper limbs, sustained posture without adequate break time and without appropriate ergonomic arrangement is also correlated with neurological, inflammatory, and other upper-limb pathology as well as parafunction originating from the deep musculature of the neck (Threesittidath et. al., 2024) owing to a potential broader pattern of compensatory maladaptation, (Jeon et. al., 2019) all of which is amenable to early intervention through good work design (Pascarelli & Hsu, 2001). The picture is similar in lower back pain, where poorer endurance and increased sitting time (O’Sullivan et. al., 2006), impaired core control and increased standing time (Halim et. al., 2011) are all positively correlated with the incidence of work-related discomfort.
It’s not a matter of use it or lose it. Quite simply, use it right. Or else.
The maintenance of appropriate posture depends on how a person uses their body and how aware they are of what they are doing. People are obliged to balance the demands of their health, their work, their families and friends, their commitments, and so many other obligations. In the middle of that, it is easy to forget that a person is a living, breathing, acting body. So much is made of paying attention to posture, of having good posture, of standing so upright with the shoulders so far back and having so much of a curve in the lower spine, but ultimately the prevention of postural irritation relies on the same principles as injury risk mitigation generally (SWA, 2020). Postural irritation arises from having spent too much time at a task with too few breaks. Employers and owners can either design work to allow breaks or alternation of duties or make breaks accessible in the workplace. Business managers can also consider the effect of interventional exercise in the workplace, where the break is combined with light, nonvigorous physical activity that moves through different poses and different stretches so as to engage those muscles and joints that might otherwise only be working. This is doubly important for trades workers who, by virtue of the physicality of their jobs, need to use their bodies more vigorously throughout the day. Posture and physical uprightness is a clinical bogeyman whose association with clinical antecedent is as appropriate as the historical correlation of posture with moral firmness (Jesson, 2017). By focusing on individual posture and anatomical arrangement rather than activities, environments, design and obligation, the discussion misses the opportunity to control the exposure at the source and design a model of work and job roles that doesn’t impose inappropriate or accumulative strain on a worker. Businesses should review the activities their workers are required to undertake, within broader consideration of how work is organised individually, spatially, and organisationally, and review how these arrangements can predispose or protect workers from accumulations of strain in the long term or overloads of stress in the short term that result in injury, time off, and lost productivity.
None of this information constitutes medical, legal, occupational health and safety, best guidance, standard, or other guidance, instruction, or prescription.
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References
Australian Bureau of Statistics. (2022). Journey to work. Retrieved 27th January 2025 from https://www.abs.gov.au/articles/australias-journey-work
Australian Bureau of Statistics. (2023). Physical activity. Retrieved 27th January 2025 from https://www.abs.gov.au/statistics/health/health-conditions-and-risks/physical-activity/latest-release
Australian Institute of Health and Welfare. (2024). Physical Activity. Retrieved 27th January 2025 from https://www.aihw.gov.au/reports/physical-activity/physical-activity
Baker, R., Coenen, P., Howie, E., Williamson, A., & Straker, L. (2019). The musculoskeletal and cognitive effects of under-desk cycling compared to sitting for office workers. Applied ergonomics, 79, 76-85.
Barbieri, D. F., Brusaca, L. A., Mathiassen, S. E., & Oliveira, A. B. (2020). Effects of time in sitting and standing on pleasantness, acceptability, fatigue, and pain when using a sit–stand desk: An experiment on overweight and normal-weight subjects. Journal of Physical Activity and Health, 17(12), 1222-1230.
Barrett, E., O'Keeffe, M., O'Sullivan, K., Lewis, J., & McCreesh, K. (2016). Is thoracic spine posture associated with shoulder pain, range of motion and function? A systematic review. Manual Therapy, 26, 38-46
Bleecker, M. L., Celio, M. A., & Barnes, S. K. (2011). A medical-ergonomic program for symptomatic keyboard/mouse users. Journal of occupational and environmental medicine, 53(5), 562-568.
Bontrup, C., Taylor, W. R., Fliesser, M., Visscher, R., Green, T., Wippert, P. M., & Zemp, R. (2019). Low back pain and its relationship with sitting behaviour among sedentary office workers. Applied ergonomics, 81, 102894.
Bougard, C., Lepelley, M. C., & Davenne, D. (2011). The influences of time-of-day and sleep deprivation on postural control. Experimental brain research, 209, 109-115.
Caneiro, J. P., O'Sullivan, P., Burnett, A., Barach, A., O'Neil, D., Tveit, O., & Olafsdottir, K. (2010). The influence of different sitting postures on head/neck posture and muscle activity. Manual Therapy, 15(1), 54-60.
Chapman, C. R., Tuckett, R. P., & Song, C. W. (2008). Pain and stress in a systems perspective: reciprocal neural, endocrine, and immune interactions. The Journal of Pain, 9(2), 122-145.
De Carvalho, D., Greene, R., Swab, M., & Godwin, M. (2020). Does objectively measured prolonged standing for desk work result in lower ratings of perceived low back pain than sitting? A systematic review and meta-analysis. Work, 67(2), 431-440.
Comcare. n.d. Body Stressing: A Risk Management Snapshot. Retrieved 25th January from https://www.comcare.gov.au/about/forms-pubs/docs/pubs/safety/body-stressing-risk-management-snapshot.pdf
Demoulin, C., Crielaard, J. M., & Vanderthommen, M. (2007). Spinal muscle evaluation in healthy individuals and low-back-pain patients: a literature review. Joint Bone Spine, 74(1), 9-13.
Earhart, G. M. (2013). Dynamic control of posture across locomotor tasks. Movement disorders, 28(11), 1501-1508.
Fabbri, M., Martoni, M., Esposito, M. J., Brighetti, G., & Natale, V. (2006). Postural control after a night without sleep. Neuropsychologia, 44(12), 2520-2525.
Gobbo, S., Bullo, V., Bergamo, M., Duregon, F., Vendramin, B., Battista, F., Roma, E., Bocalini, D.S., Rica, R.L., Alberton, C.L., & Bergamin, M. (2019). Physical exercise is confirmed to reduce low back pain symptoms in office workers: A systematic review of the evidence to improve best practices in the workplace. Journal of Functional Morphology and Kinesiology, 4(3), 43.
Goyal, J., & Rakhra, G. (2024). Sedentarism and chronic health problems. Korean Journal of Family Medicine, 45(5), 239.
Greenfield, B., Catlin, P. A., Coats, P. W., Green, E., McDonald, J. J., & North, C. (1995). Posture in patients with shoulder overuse injuries and healthy individuals. Journal of Orthopaedic & Sports Physical Therapy, 21(5), 287-295.
Gribble, P. A., Tucker, W. S., & White, P. A. (2007). Time-of-day influences on static and dynamic postural control. Journal of athletic training, 42(1), 35.
Halim, I., Omar, A. R., Saman, A. M., & Othman, I. (2011). A review on health effects associated with prolonged standing in the industrial workplaces. International Journal of Research and Reviews in Applied Sciences, 8(1), 14-21.
Halpern, A. I., Jansen, J. A., Giladi, N., Mirelman, A., & Hausdorff, J. M. (2022). Does Time of Day influence postural control and gait? A review of the literature. Gait & posture, 92, 153-166.
Hanna, F., Daas, R. N., El-Shareif, T. J., Al-Marridi, H. H., Al-Rojoub, Z. M., & Adegboye, O. A. (2019). The Relationship Between Sedentary Behavior, Back Pain, and Psychosocial Correlates Among University Employees. Frontiers in public health, 7, 80.
Haslegrave, C. M. (1994). What do we mean by a ‘working posture’? Ergonomics, 37(4), 781-799.
Hennessey, L., & Watson, A. W. (1993). Flexibility and posture assessment in relation to hamstring injury. British journal of sports medicine, 27(4), 243-246.
Jaffar, N., Abdul-Tharim, A. H., Mohd-Kamar, I. F., & Lop, N. S. (2011). A literature review of ergonomics risk factors in construction industry. Procedia engineering, 20, 89-97.
Jeon, I. C., Kwon, O. Y., Hwang, U. J., Jung, S. H., & Weon, J. H. (2019). Increased scapular anterior tilting and decreased humeral internal rotation in the mouse shoulder in computer workers with shoulder pain. Executive Editor, 13(2), 111.
Jesson, T. (2017). Upright and uptight: the invention of posture. Retrieved 27th January 2025 from https://medium.com/@thomas_jesson/upright-and-uptight-the-invention-of-posture-fe48282a4487
Johnston, V., Gane, E. M., Brown, W., Vicenzino, B., Healy, G. N., Gilson, N., & Smith, M. D. (2019). Feasibility and impact of sit-stand workstations with and without exercise in office workers at risk of low back pain: A pilot comparative effectiveness trial. Applied Ergonomics, 76, 82-89.
Kumar, S. (2001). Theories of musculoskeletal injury causation. Ergonomics, 44(1), 17-47.
Magnusson, M. L., & Pope, M. H. (1998). A review of the biomechanics and epidemiology of working postures (it isn't always vibration which is to blame!). Journal of sound and vibration, 215(4), 965-976.
Mannion, A. F. (1999). Fibre type characteristics and function of the human paraspinal muscles: normal values and changes in association with low back pain. Journal of electromyography and kinesiology, 9(6), 363-377.
Nelson-Wong, E., Gallagher, K., Johnson, E., Antonioli, C., Ferguson, A., Harris, S., Johnson, H., & Miller, J. B. (2020). Increasing standing tolerance in office workers with standing-induced back pain. Ergonomics, 63(7), 804-817.
Ognibene, G. T., Torres, W., von Eyben, R., & Horst, K. C. (2016). Impact of a sit-stand workstation on chronic low back pain: results of a randomized trial. Journal of occupational and environmental medicine, 58(3), 287-293.
O’Sullivan, P. B., Mitchell, T., Bulich, P., Waller, R., & Holte, J. (2006). The relationship beween posture and back muscle endurance in industrial workers with flexion-related low back pain. Manual therapy, 11(4), 264-271.
Papegaaij, S., Taube, W., van Keeken, H. G., Otten, E., Baudry, S., & Hortobágyi, T. (2016). Postural challenge affects motor cortical activity in young and old adults. Experimental Gerontology, 73, 78-85.
Pascarelli, E. F., & Hsu, Y. P. (2001). Understanding work-related upper extremity disorders: clinical findings in 485 computer users, musicians, and others. Journal of Occupational Rehabilitation, 11, 1-21.
Podrekar, N., Kozinc, Ž., & Šarabon, N. (2020). The effects of cycle and treadmill desks on work performance and cognitive function in sedentary workers: A review and meta-analysis. Work, 65(3), 537-545.
Popa, T., Bonifazi, M., Della Volpe, R., Rossi, A., & Mazzocchio, R. (2007). Adaptive changes in postural strategy selection in chronic low back pain. Experimental brain research, 177, 411-418.
Van Poppel, M. N., Hooftman, W. E., & Koes, B. W. (2004). An update of a systematic review of controlled clinical trials on the primary prevention of back pain at the workplace. Occupational Medicine, 54(5), 345-352.
Safe Work Australia. (n.d.) Sitting and standing. Retrieved 27th January 2025 from https://www.safeworkaustralia.gov.au/safety-topic/hazards/sitting-and-standing
Safe Work Australia. (2020) Model Code of Practice, Hazardous Manual Tasks. Retrieved 27th January 2025 from https://www.safeworkaustralia.gov.au/doc/model-code-practice-hazardous-manual-tasks
Sandler, H. (2012). Inactivity: physiological effects. Elsevier.
Slater, D., Korakakis, V., O'Sullivan, P., Nolan, D., O'Sullivan, K. (2019). Sit up straight: time to re-evaluate. JOSPT 49(8):562-4.
Stock, S. R. (1991). Workplace ergonomic factors and the development of musculoskeletal disorders of the neck and upper limbs: A meta‐analysis. American journal of industrial medicine, 19(1), 87-107.
Threesittidath, K., Chaibal, S., & Nitayarak, H. (2024). Effects of an hour computer use on ulnar and median nerve conduction velocity and muscle activity in office workers. Journal of Occupational Health, 023.
Vieira, E. R., & Kumar, S. (2004). Working postures: a literature review. Journal of occupational rehabilitation, 14, 143-159.
Williams, R. M., Westmorland, M. G., Lin, C. A., Schmuck, G., & Creen, M. (2007). Effectiveness of workplace rehabilitation interventions in the treatment of work-related low back pain: a systematic review. Disability and rehabilitation, 29(8), 607-624.
Zernicke, R. F., & Whiting, W. C. (2000). Mechanisms of musculoskeletal injury. Biomechanics in Sport: Performance Enhancement and Injury Prevention, 507-522.
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