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Seeking the Optimal Posture of the Seated Lumbar Spine
Physiotherapy Theory and Practice
Abstract
Prolonged sitting with poor posture is associated with the development of lower
back pain. Ergonomic texts for physiotherapists contain diverging and confusing
views on recommended postures for the lumbar spine when seated that will
promote postural health and optimal functioning of the lumbar spine. A review of
the literature reveals that proponents of both the lordosed and kyphosed lumbar
seated position use similar arguments with contradictory conclusions. The
arguments of those advocating the kyphosed lumbar seated posture are, however,
often anecdotal and unsubstantiated by research. This paper evaluates the
con icting views and concludes that the lordosed seated posture, regularly
interspersed with movement, is the optimal sitting posture and assists in
maintaining lumbar postural health and preventing low back pain.
... However, in the context of teacher-directed or learner-directed physical classrooms, sitting position has been widely recognized, given the fact that average classroom learning takes place while sitting. Yet, optimal sitting posture for learning is still debatable in the literature as there is no ideal sitting position (Pynt et al., 2001). Research on human psychological behavior has found a significant association between sitting position and metacognition or attention (Yang et al., 2021). ...
... The insignificant contribution of these variables could be explained from the viewpoint of uncertainties surrounding their learning benefits. For example, Pynt et al. (2001) argued that there is no ideal sitting posture in learning; what matters most is the learner's attention. Other research evidence has also shown that note-taking does not improve students' performance, rather, the latter is improved by the strategies used in the notetaking behavior (Castello & Monereo, 2005;Chen, 2019). ...
Studies examining students’ learning behavior predominantly employed rich video data as their main source of information due to the limited knowledge of computer vision and deep learning algorithms. However, one of the challenges faced during such observation is the strenuous task of coding large amounts of video data through repeated viewings. In this research, we confirm the possibilities of classifying students’ learning behavior using data obtained from multimodal distribution. We employed computer algorithms to classify students’ learning behavior in animated programming classrooms and used information from this classification to predict learning outcomes. Specifically, our study indicates the presence of three clusters of students in the domain of “stay active”, “stay passive”, and “to-passive”. We also found a relationship between these profiles and learning outcomes. We discussed our findings in accordance with the engagement and instructional quality models and believed that our statistical approach will support the ongoing refinement of the models in the context of behavioral profiling and classroom interaction. We recommend that further studies should identify different epistemological frames in diverse classroom settings to provide sufficient explanations of students’ learning processes.
... However, despite the development of ergonomics regarding the manufacture of chairs and furniture used in workstations, these instruments were not very effective in preventing low back pain. Therefore, currently, the main focus for reducing the occurrence of this musculoskeletal symptom is the introduction of exercise and the adoption of postural reeducation programs [6]. ...
Aims: The objective of the present study was to verify the relationship between musculoskeletal pain and kinematic factors of sitting posture in university staff at the University of Middle-West –UNICENTRO. Methodology: The sample studied was 24 university agents from a total of 40 employees. Anthropometric data were collected by record and to assess the prevalence of pain, a standardized questionnaire was used. The employee positioning variables were: popliteal height, elbow-to-seat height, table height and thigh height. The arrangement of the workstation was also evaluated, checking the position of the computer and/or other equipment for daily use. Results: It was found that 54.16% of the agents had some type of pain in the spine. The recommended chair seat for men would be a height of 44.3 cm and was found to be 50.2 cm, while for women the recommended height is 40.9 cm and was found to be 45.1 cm. Conclusion: According to the results obtained, the height of the table was higher than recommended, which could perhaps justify the complaint of pain reported by university agents.
... However, in the context of teacher-directed or learner-directed physical classrooms, sitting position has been widely recognized, given the fact that average classroom learning takes place while sitting. Yet, optimal sitting posture for learning is still debatable in the literature as there is no ideal sitting position (Pynt et al., 2001). Research on human psychological behavior has found a signi cant association between sitting position and metacognition or attention (Yang et al., 2021). ...
Studies examining students’ learningbehavior predominantly employed rich video data as their main source of information due to the limited knowledge of computer vision and deep learning algorithms. However, one of the challenges faced during such observation is the strenuous task of coding large amounts of video data through repeated viewings. In this research, we confirm the possibilities of classifying students’ learning behavior using data obtained from multimodal distribution. We employed computer algorithms to classify students’ learning behavior in animated programming classrooms and used information from this classification to predict learning outcomes. Specifically, our study indicates the presence of three clusters of students in the domain of “stay active”, “stay passive”, and “to-passive”. We also found a relationship between these profiles and learning outcomes. We discussed our findings in accordance with the engagement and instructional quality models and believed that our statistical approach will support the ongoing refinement of the models in the context of behavioral profiling and classroom interaction. We recommend that further studies should identify different epistemological frames in diverse classroom settings to provide sufficient explanations of students’ learning processes.
... The long-standing belief of sitting "as upright as possible" has been slowly replaced by the concept of "dynamic" or "active sitting" where sitting positions are changed as often as possible [6,7]. Yet again, a literature review [8] suggests that there is no ideal sitting posture, and for preventing low back pain, one should sit with a preferred lumbar lordosis and, in addition, move regularly. Frequent position changes for office workers, which include working in a standing position and moving regularly, are usually recommended by ergonomics experts and physiotherapists to avoid work-related discomfort and injuries [9]. ...
In this paper, a smart office chair with movable textile sensors to monitor sitting position during the workday is presented. The system consists of a presence textile capacitive sensor with different levels of activation with a signal conditioning device. The proposed system was integrated into an office chair to detect postures that could provoke musculoskeletal disorders or discomfort. The microcontroller measured the capacitance by means of a cycle count method and provided the position information in real time. The information could be analysed to set up warnings to prevent incorrect postures or the necessity to move. Five participants assumed a series of postures, and the results showed the workability of the proposed smart chair. The chair can be provided as a new tool for companies, hospitals, or other institutions to detect incorrect postures and monitor the postures of people with reduced mobility. This tool can optimise control procedures or prevent occupational risks.
... In addition to applying a different amount of pressure to the spine, prolonged sitting also brings a number of health problems, such as lumbar pain, thigh masses, and cardiovascular diseases. In particular, sitting for prolonged periods of time with bad posture, such as sitting hunched over or cross-legged, can lead to lower heart rates and poorer blood circulation, which indirectly affect the lymphatic system, cause lymphatic obstruction in subcutaneous tissue, promote the accumulation of interstitial fluid in subcutaneous tissue, and prevent toxic substances from being effectively removed (Andrew et al., 2018;Castanharo et al., 2014;Chris et al., 2006;Hadgraft et al., 2016;Pynt et al., 2001). These can then result in chronic diseases such as diabetes and hypertension (Dunstan et al., 2012). ...
In recent years, the relationship between sitting posture and health has been paid attention to by researchers, since a person spends about 90% of a day sitting except for sleeping time, and the prolonged sitting is one of the important causes of musculoskeletal diseases. Basically, the different sitting postures caused by sitting for a long time will cause different pressure problems on the spine. Thus, this study intends to accurately predict sitting posture to reduce the damage caused by sitting posture using random forest. A smart chair with eight pressure sensors provided by a case company in Taiwan is applied to collect pressure data of various sitting postures in order to develop a prediction model to predict the sitting posture. Since random forest also owns the capability of feature extraction, it is also employed to find unnecessary sensors to reduce the cost of smart chair and further achieve higher prediction accuracy. The results showed that random forest can yield better results for the current problem compared with other methods. In addition, after the feature extraction via random forest, it can be known that there is indeed a sensor that can be eliminated. The accuracy can be enhanced from 90.70% to 91.36%.
... In addition, in [15] it is highlighted that there is no ideal posture that can be called ideal; however, a healthy posture is characterized as one that prevents compensatory movements, properly distributes loads and conserves energy. In [13], [16], are described as recommended (low-risk postures) to normal lumbar lordosis with lumbar support, normal thoracic kyphosis, and lateral symmetry. ...
Nowadays, service-providing employment accounts for about 80% of jobs [1], most of which require low physical activity. This sedentary behavior is carried out by workers who are mainly seated for long periods and usually also includes postural behavior that can cause pain and chronic injuries. To increase worker well-being, in addition to encouraging and promoting physical activities, posture monitoring can be helpful in identifying wrong behaviors, leading to less postural stress and musculoskeletal injuries. This paper presents a non-intrusive posture monitoring system, based on a matrix of pressure sensors inserted on a chair cushion, where the worker is seated. The gathered data is then subject to a machine learning algorithm that can infer favorable/unfavorable postures. The results lead to more than 80% accuracy, which means that this setup can be helpful in informing users of their postures that lead to their correction, thus helping to mitigate pain and injuries.
Introduction
Inactivity and long periods of sitting are common in our society, even though they pose a health risk. Dynamic sitting is recommended to reduce this risk. The purpose of this study was to investigate the effect of continuous passive motion (CPM) conducted by a novel motorized office chair on lumbar lordosis and trunk muscle activation, oxygen uptake and attentional control.
Study design
Randomized, single-session, crossover with two periods/conditions.
Methods
Twenty office workers (50% women) sat for one hour on the motorized chair, one half with CPM, the other not. The starting condition (CPM/no CPM) was switched in half of the sample. The participants were equipped with a spirometric cart, surface EMG, the Epionics SPINE system and performed a computer-based test for attentional control (AX-CPT). Outcomes were lumbar sagittal movements and posture, number of trunk muscle activations, attentional control and energy expenditure.
Results
The CPM of the chair causes frequent low-amplitude changes in lumbar lordosis angle (moved: 498 ± 133 vs. static: 45 ± 38) and a higher number of muscle activations. A periodic movement pattern of the lumbar spine according to the movement of the chair was observed in every participant, although, sitting behavior varied highly between individuals. Attentional control was not altered in the moved condition (p = .495; d = .16). Further, oxygen uptake did not increase higher than 1.5 MET.
Conclusion
The effects of the motorized chair can be particularly useful for people with static sitting behavior. Further studies should investigate, whether CPM provides the assumed beneficial effects of dynamic sitting on the spine.
We investigated the distribution of compressive ‘stress’ within cadaver intervertebral discs, using a pressure transducer mounted in a 1.3 mm diameter needle. The needle was pulled along the midsagittal diameter of a lumbar disc with the face of the transducer either vertical or horizontal while the disc was subjected to a constant compressive force. The resulting ‘stress profiles’ were analysed in order to characterise the distribution of vertical and horizontal compressive stress within each disc. A total of 87 discs from subjects aged between 16 and 87 years was examined.
Our results showed that age-related degenerative changes reduced the diameter of the central hydrostatic region of each disc (the ‘functional nucleus’) by approximately 50%, and the pressure within this region fell by 30%. The width of the functional annulus increased by 80% and the height of compressive ‘stress peaks’ within it by 160%. The effects of age and degeneration were greater at L4/L5 than at L2/L3, and the posterior annulus was affected more than the anterior. Age and degeneration were themselves closely related, but the stage of degeneration had the greater effect on stress distributions.
We suggest that structural changes within the annulus and endplate lead to a transfer of load from the nucleus to the posterior annulus. High ‘stress’ concentrations within the annulus may cause pain, and lead to further disruption.
Sitting postures on a knee-support (Balans®) chair and a tiltable chair were investigated with 12 healthy subjects during office work and simulated assembly work. After at least 3 weeks' adaptation to each chair, the subjects were investigated for 1 hour on each chair in stratified sequence. Postures were evaluated by means of a statometric method. Spinal load was further estimated by measuring stature shrinkage over each sitting period. Energy consumption was roughly assessed by pulse measurements. Finally, subjective acceptability was rated by a 5-point scale. Posture effects of the Balans® chair, taken in relation to the tiltable chair, were primarily a forward tilt of the pelvis and a change toward lumbar lordosis. Secondly, the trunk was vertical compared to the slightly backward-inclined position in the tiltable chair. The head was most vertical in the Balans® chair. No effect on spinal shrinkage or pulse was observed. The subjective rating seemed to favour the tiltable chair if used over longer periods. However, the Balans(®) chair may be a good alternative for some seated periods and special tasks.
An investigation was undertaken to determine whether it was possible to achieve equivalent or greater postural improvement, in terms of spinal posture, positional variety and comfort, on a traditional chair modified by design changes to the seat surface to that of a forward sloping chair. Forward sloping chairs have the disadvantage that the body tends to slide forwards off the seat and the possibilities for position change are limited in that leaning backwards is awkward. Theoretically a chair should support a variety of body positions thus allowing the relaxation of alternate groups of muscles (encouraging dynamic seating behaviour). The modified design retains the traditional slightly concave surface for the area under the ischial tuberosities but the front 18 cm is angled downward. Results were obtained using a measuring technique which incorporates the dynamic movement patterns of working people. They indicate that the modified form can be used to achieve similar postural changes to the traditional form when sloped forwards for both assembly work and VDU work. Additionally a wider range of seating positions is adopted on it. Although forward thrust was not reduced the design was rated as more comfortable. This raised questions about whether discomfort is directly related to forward thrust. The issue of table height was also raised.