Thoracic and lumbar posture behaviour in sitting tasks and standing: Progressing the biomechanics from observations to measurements

Thoracic spinal postures and mobility in patients with cervicogenic headache versus asymptomatic healthy controls: A longitudinal study

INTRODUCTION

Studies analyzing postures and mobility of the thoracic spine in the context of cervicogenic headache are missing. Insight in these parameters is needed since the cervical and thoracic spine are biomechanically related.

OBJECTIVE

To compare self-perceived optimal and habitual postures, active-assisted maximal range of motion, and repositioning error of the upper-thoracic and lower-thoracic spine between a cervicogenic headache-group and matched healthy control-group before and after a 30 min-laptop-task.

METHODS

A non-randomized longitudinal design was used to compare thoracic postures and mobility between 18 participants with cervicogenic headache (29-51 years) and 18 matched healthy controls (26-52 years). Outcomes were: self-perceived optimal and habitual postures, active-assisted maximal range of motion, and repositioning error of the upper-thoracic and lower-thoracic spine evaluated in sitting with a 3D-Vicon motion analysis system.

RESULTS

Habitual upper-thoracic postures in the cervicogenic headache-group were significantly (p = .04) less located toward the maximal range of motion for flexion compared to the control-group, self-perceived optimal upper-thoracic posture was significantly (p = .004) more extended in the cervicogenic headache-group compared to the control-group, and self-perceived optimal lower-thoracic posture could not be reestablished in the cervicogenic headache-group after the laptop-task (p = .009).

CONCLUSION

Thoracic postures differ between a cervicogenic headache-group and control-group. These differences were detected by expressing the habitual thoracic posture relative to its maximal range of motion, and by analyzing the possibility of repositioning the thoracic spine after a headache provoking activity. Longitudinal studies are needed to determine the contribution of these musculoskeletal dysfunctions to the pathophysiology of cervicogenic headache.

The effect of various therapeutic exercises on forward head posture, rounded shoulder, and hyperkyphosis among people with upper crossed syndrome: a systematic review and meta-analysis

OBJECTIVES

This review study aimed to evaluate the impact of therapeutic exercises on Upper-Crossed Syndrome (UCS). The study utilized a systematic review and meta-analysis approach to investigate the effects of various therapeutic exercises on forward head posture, rounded shoulders, and hyperkyphosis associated with upper crossed syndrome.

METHODS

The study identified relevant keywords for each independent and dependent variable and conducted a search in scientific databases, including PubMed, Web of Science, Scopus, and Google Scholar, without any time limitations until 12 August 2023. Overall, 4625 articles were found in the selected databases, which were reduced to 1085 after being entered into the EndNote software and removing duplicate data. The full texts of 30 remaining studies were reviewed; ten articles meeting the criteria were included. Additionally, 12 studies from the Google Scholar database were included, resulting in 22 studies. Using Comprehensive meta-analysis software (CMA ver 3), data heterogeneity was measured with I2 and the Q tests. The Funnel Plot and Egger test methods were utilized to determine the possibility of publication bias. The JBI checklist was used to assess the quality of the studies.

RESULTS

The results of the meta-analysis showed that therapeutic exercises were effective in improving forward head, rounded shoulders, and thoracic kyphosis angles (CI 95% = -1.85-1.161, P = 0.001, P = 0.001, CI95%=-1.822-1.15, and P = 0.001, CI 95%= -1.83-1.09, respectively).

CONCLUSION

Based on the results, it appears that performing therapeutic exercises in the form of strength exercises, stretching, shoulder-based exercises, and incredibly comprehensive exercises that target all muscles may be effective in reducing forward head, rounded shoulders, thoracic kyphosis, and overall UCS.

LEVEL OF EVIDENCE: 1

Forced Straightening of the Back Does Not Improve Body Shape

BACKGROUND

Sitting for a long time causes various postural problems, such as slump sitting. It has been reported that employing a corrected sitting position while lifting the sternum is effective in improving this form of posture. We investigated how a corrected sitting posture with the lifting of the sternum is different from a forced position that is applied through the command and passive positions.

MATERIALS AND METHODS

The postural angle of 270 subjects aged 19-23 years was measured in the passive, forced, and corrected positions using a Saunders inclinometer and a Formetric 4D system.

RESULTS

As a result, the corrected position had a small range (min-max) at all angles, but the forced position and passive position had a large range (min-max). The lumbar lordosis angle in the corrected position showed positive values throughout its range (min-max), while the other groups showed negative values, which indicates the kyphotic position of the lumbar section. In addition, the percentage error in the corrected position was small, but it presented high values in the other groups. When comparing the average angles between the groups, there were substantial changes observed between the corrected position and the other groups. It was found that the corrected position with the sternum lifted, which is applied to improve slump sitting in the clinical environment, exhibited an angle that differed from that of the forced position and the passive position.

CONCLUSIONS

Our results suggest that a forced position on the command "scapular retraction" does not meet the clinical assumptions of posture correction, in contrast to the corrected position with the lifting of the sternum for the improvement of slump sitting. The accurate correction of the position of the sternum and sacrum improves the position of the spine in the sagittal plane, enabling physiological values for the kyphosis and lordosis angle parameters to be obtained. This approach combines the ease of execution and precision of the effect. The fact that this method does not require complex tools to accurately correct the body encourages the implementation of this solution in clinical practice.

Gender, Sex and Desk-Based Postural Behaviour: A systematic review re-interpreting biomechanical evidence from a social perspective

BACKGROUND

Biomechanical and pain prevalence differences between sex/gender groups are frequently attributed to biological differences between sexes without considering the influence of socially-constructed gender. This may lead to interventions which are insufficient and culturally unresponsive. This review reinterprets the evidence regarding differences in desk-based postural behaviour between sex/gender groups from a gender-based perspective.

METHODS

Four prominent databases were searched using terms such as 'desk based', 'posture', and 'position'. Articles were included if they objectively investigated desk-based positional variability, postural variability and/or habitual alignment in healthy adults.

RESULTS

Nine studies were included. Differences were found in postural variability and habitual alignment between sex/gender groups and were not explored from a gender-based perspective.

CONCLUSION

Gender-based expectations regarding 'acceptable' posture and movement likely contribute to biomechanical and pain differences between genders. This should be considered by clinicians intending to affect patients' movement and postural patterns and by researchers working in this space.

Gender-based analysis of muscle activation while in a sedentary work posture

BACKGROUND

Many people work in a sitting position where they have to use their upper extremities and hands. Muscle activity in sitting position is affected by the chair height of, the height of the worktable, and the distance to the working target.

OBJECTIVE

The purpose of this study is to investigate differences in muscle activity between men and wemen at different chair heghts and working distances.

METHODS

Surface electromyography (EMG) was employed to determine the muscle activity of the upper limbs and the trunk, while an arm-stretching task was performed in a sitting position.

RESULTS

Women's muscle activity was higher than that of men in most muscles as the chair height and working distance changed.

CONCLUSIONS

As the height of the chair or the working distance was changed, muscle activity was greater in women than in men for most of the muscles analyzed. Under the same conditions, women may feel more muscle fatigue than men, so it is necessary to consider gender in the working environment.

Sedentary lifestyle of university students is detrimental to the thoracic spine in men and to the lumbar spine in women

BACKGROUND

Sitting for long periods of time and lack of physical activity in young adults can cause postural deterioration leading to rapid onset of fatigue and increase the risk of back pain. We were interested in whether there are gender differences in spinal curvature among university students with a predominantly sedentary lifestyle.

METHODS

20 sedentary female (age 20 ± 0.73 years) and 39 sedentary male university students (age 20 ± 1.08 years) participated in this study. Their thoracic and lumbar curvatures were assessed while standing and sitting using a Spinal Mouse.

RESULTS

In standing, 80.0% of the females and 69.2% of the males had a neutral position of the thoracic spine (33.25° and 35.33°, respectively). However, more males, 30.8%, than females, 10.0%, had hyperkyphosis (54.27° and 47.0°, respectively). Hypokyphosis was found in 10.0% of the females (18.50°) and none in the males. Similarly, 90.0% of the females and 97.4% of the males had neutral position of the lumbar spine (-33.11° and -29.76°, respectively). Increased hyperlordosis was found in 10.0% of the females and 2.6% of the males (-41.0° and -50.0°, respectively). Hypolordosis was not detected in either females or males. In sitting, on the other hand, 70.0% of the females and only 33.3% of the males had a neutral position of the thoracic spine (30.20° and 30.62°, respectively). Increased hyperkyphosis was found in 46.2% of the males (59.76°) and none of the females. 30.0% of the females and 23.1% of the males had light hypokyphosis (47.50° and 46.67°, respectively). Similarly, 70.0% of the females and only 38.5% of the males had a neutral position of the lumbar spine (7.0° and 6.6°, respectively). 35.9% of the males and only 5.0% of the females had a light hypokyphosis (16.14° and 16.0°, respectively). Slightly increased hyperkyphosis was identified in 25.6% of the males and 25.0% of the females (23.9° and 22.5°, respectively).

CONCLUSION

There are significant gender differences in spinal curvature. While in the thoracic spine it was to the detriment of the males when both standing and sitting, in the lumbar spine it is related to the females only when standing. It is therefore necessary to eliminate these spinal deviations in young adults induced by prolonged sitting during university courses by appropriate recovery modalities.

Alternative to Reduced Stresses on the Upper Extremity in a Standing Workstation

OBJECTIVE

This study evaluated a standing armrest to provide more acceptable ergonomic guidelines that may reduce the cost of standing computer workstations.

BACKGROUND

Of the many advantages of standing workstations, there have been no efforts to minimize the biomechanical cost, such as larger wrist extension and greater forearm muscle activity than sitting.

METHOD

Sixteen participants were asked to perform a typing task under a combination of the following factors: (1) desk shape (rectangular and concave); (2) desk height (0, +5, -5 cm from 90° elbow flexion); and (3) monitor height (0, -10 cm from the eyes). During the trials, the trunk kinematics, muscle activation levels, and CoP were recorded.

RESULTS

Both arms were further away from the upper body under the concave and +5 desk height than under the normal condition, but significant decreases in the extensor carpi radialis (8.6%), anterior deltoid (28.8%), and L4 paraspinals (5.5%) were observed. Similarly, the wrist extension angle decreased by 10.5° (42%) under this condition, but the posture required a 2.2° (19%) increase in wrist adduction angle. The CoP irregularity was greater under the concave workstation, indicating more complex motion.

CONCLUSION

A higher and concave desk can provide an armrest effect while engaged in a standing workstation by reducing the wrist extension and related muscle activation level, but at the cost of a larger wrist adduction angle.

APPLICATION

Providing a standing armrest (+5 cm height and concave desk) could reduce the stresses on the upper extremities, but a split keyboard should be considered to minimize wrist adduction.

Biomechanical response of lumbar intervertebral disc in daily sitting postures: a poroelastic finite element analysis

This study aims to establish and validate a poroelastic L4-L5 finite element model to evaluate the effect of different sitting postures and their durations on the mechanical responses of the disc. During the sustained loading conditions, the height loss, fluid loss and von-Mises stress gradually increased, but the intradiscal pressure decreased. The varying rates of aforementioned parameters were more significant at the initial loading stage and less so at the end. The predicted values in the flexed sitting posture were significantly greater than other postures. The extended sitting posture caused an obvious von-Mises stress concentration in the posterior region of the inter-lamellar matrix. From the biomechanical perspective, prolonged sitting may pose a high risk of lumbar disc degeneration, and therefore adjusting the posture properly in the early stage of sitting time may be useful to mitigate that. Additionally, upright sitting is a safer posture, while flexed sitting posture is more harmful.

Stereophotogrammetric approaches to multi-segmental kinematics of the thoracolumbar spine: a systematic review

BACKGROUND

Spine disorders are becoming more prevalent in today's ageing society. Motion abnormalities have been linked to the prevalence and recurrence of these disorders. Various protocols exist to measure thoracolumbar spine motion, but a standard multi-segmental approach is still missing. This study aims to systematically evaluate the literature on stereophotogrammetric motion analysis approaches to quantify thoracolumbar spine kinematics in terms of measurement reliability, suitability of protocols for clinical application and clinical significance of the resulting functional assessment.

METHODS

Electronic databases (PubMed, Scopus and ScienceDirect) were searched until February 2022. Studies published in English, investigating the intersegmental kinematics of the thoracolumbar spine using stereophotogrammetric motion analysis were identified. All information relating to measurement reliability; measurement suitability and clinical significance was extracted from the studies identified.

RESULTS

Seventy-four studies met the inclusion criteria. 33% of the studies reported on the repeatability of their measurement. In terms of suitability, only 35% of protocols were deemed suitable for clinical application. The spinous processes of C7, T3, T6, T12, L1, L3 and L5 were the most widely used landmarks. The spine segment definitions were, however, found to be inconsistent among studies. Activities of daily living were the main tasks performed. Comparable results between protocols are however still missing.

CONCLUSION

The literature to date offers various stereophotogrammetric protocols to quantify the multi-segmental motion of the thoracolumbar spine, without a standard guideline being followed. From a clinical point of view, the approaches are still limited. Further research is needed to define a precise motion analysis protocol in terms of segment definition and clinical relevance.

Physical Load While Using a Tablet at Different Tilt Angles during Sitting and Standing

Few standards and guidelines to prevent health problems have been associated with tablet use. We estimated the effects of posture and tablet tilt angle on muscle activity and posture in healthy young adults. Seventeen healthy young adults (age: 20.5 ± 3 years) performed a cognitive task using a tablet in two posture (sitting and standing) and tablet tilt angle (0 degrees and 45 deg) conditions. Segment and joint kinematics were evaluated using 16 inertial measurement unit sensors. Neck, trunk, and upper limb electromyography (EMG) activities were monitored using 12 EMG sensors. Perceived discomfort, kinematics, and EMG activities were compared between conditions using the Friedman test. The perceived discomfort in the standing-0 deg condition was significantly higher than in the remaining three conditions. Standing posture and tablet inclination significantly reduced the sagittal segment and joint angles of the spine, compared with sitting and flat tablet conditions. Similarly, standing posture and tablet inclination significantly reduced EMG activities of the dorsal neck, upper, and lower trunk muscles, while increasing EMG activity of shoulder flexors. Standing posture and tablet inclination reduced the sagittal flexion angle, and dorsal neck, upper, and lower trunk muscle activities, while potentially increasing the muscle activity of arm flexors.

Recommended maximum holding time of common static sitting postures of office workers

PURPOSE

A posture maintained for a long period can be harmful to the health of office workers. This study aimed to estimate the recommended ergonomic duration for maintaining different sitting postures.

MATERIALS AND METHODS

Forty healthy male and female students participated in this experiment designed to measure perceived discomfort caused by maintaining common static sitting postures of office workers in a simple ergonomic setup for four minutes. The Borg CR10 scale was given to the participants to assess the discomfort in different body parts, before and after each experiment. Based on the mean group discomfort level of 2, the recommended holding time of each posture was estimated.

RESULTS

The recommended holding time and its discomfort score for each studied posture were tabulated. The shortest holding time of a posture was obtained for the moderate neck flexion (1.61 minutes), and the longest holding time was obtained for legs posture with 90-degree knee flexion (6.45 minutes).

CONCLUSIONS

The recommended holding time in this study may help to assess the risk of Musculoskeletal Disorders in office workers and train the individuals involved in office tasks in proper sitting behavior.

The effect of walking and stationary work on the acute back pain, muscle activation, posture and postural control of older women

Back pain is associated with activity such as walking or assembly line work that involves upper-body movement. However, no single study has explored the effect of these tasks on back pain, spinal angles and balance in an older adult female population. This study investigated changes in back pain, postural sway, upper-, lower- and full-spine angle and EMG activation of trunk muscles following 30 minutes of walking and a modified quiet standing task. Fourteen older adult females (62 ± 11yrs) with low to moderate chronic back pain were recruited as participants. Findings demonstrated that following these activities, increased acute back pain and upper-spine flexion occur although acute back pain was not clinically significant; postural control and muscle activation remained unchanged. This suggests that walking and modified quiet standing can lead to subtle acute back pain in older females that could be due to an increased upper spinal flexion rather than muscle fatigue. Practitioner summary: Back pain and postural problems are common in older adults. Older adult female participants experienced increased back pain and greater upper-spine flexion following 30-minute walking and standing with trunk rotation, but the practical importance was less clear. However, balance was unaffected, suggesting no increase in fall risk. Abbreviations: CBP: chronic back pain; MQS: modified quiet standing; QS: quiet standing; RPE: rating of perceived exertion; TD: trapezius descendens; TT: trapezius transversalis; TA: trapezius ascendens; ESL: erector spinae longissimus; C7: seventh cervical vertebrae; T7: seventh thoracic vertebrae; T10: tenth thoracic vertebrae; T12: twelfth thoracic vertebrae; L2: second lumbar vertebrae; S2: second sacral vertebrae; AP: anterior-posterior; ML: medial-lateral; SWAYtot: total postural sway; M: mean.

Effects of smartphone screen viewing duration and body position on head and neck posture in elementary school children

BACKGROUND

Electronic media have become integral parts of modern life, in which prolonged screen viewing time (SVT) by children is nearly unavoidable. Prolonged use of smartphones could lead to musculoskeletal problems.

OBJECTIVES

To investigate the effect of SVT on head and neck posture during and after using smartphones for various periods of time in either standing or sitting postures.

METHODS

This observational study included 34 male children aged 5-12 years who were assigned to one of two groups based on average smartphone use duration per day: group A comprised 18 children averaging > 4 hours per day (h/day) of smartphone use, and group B comprised 16 children with < 4 h/day of smartphone use. The children's postures were photographed in standing and sitting positions while using a smartphone and 30 min after ceasing smartphone use. The head flexion, neck flexion, gaze, and craniocervical angles were measured using the software program Kinovea.

RESULTS

Significant increases were found in head flexion, neck flexion, and gaze angles. Furthermore, both groups saw a significant decrease in craniocervical angle when sitting compared to when standing, both during and 30 min after smartphone use. The head flexion, neck flexion, and gaze angles of group A were significantly higher than those of group B, and the craniocervical angle of group A was significantly lower than that of group B in both postures (p< 0.05).

CONCLUSION

SVT is associated with increased neck and head flexion posture in children, especially in a sitting position.

Investigation of office workers' sitting behaviors in an ergonomically adjusted workstation

Objectives. Common ergonomic office workstations are designed for a few optimum postures. Nonetheless, sitting is a dynamic activity and the ideal sitting posture is rarely maintained in practice. Therefore, the present study aimed to investigate the sitting behavior of office workers in an actual working environment using ergonomically adjusted workstations to examine whether they promote maintaining appropriate sitting postures. Methods. Sitting behaviors (frequency of postures and position changes in different body parts) were explored among 26 office workers during a 60-min sitting duration, using the posture recording and classification method developed by Graf et al. The rapid upper limb assessment (RULA) method was also used to assess postural load. Then, the results of the RULA method were compared with the results from investigating the sitting behavior of office workers. Results. Common ergonomic workstations were effective in eliminating some awkward postures. However, some important risk factors such as holding postures with an inappropriate lumbar spine curve (86% of the observations) and maintaining a posture for a long time (for 7-12 min) were observed in the participants' sitting behaviors, while they were neglected in the RULA method. Conclusions. The common ergonomic workstations could not guarantee the users' appropriate sitting behaviors.

Improved Self-Organizing Map-Based Unsupervised Learning Algorithm for Sitting Posture Recognition System

As the intensity of work increases, many of us sit for long hours while working in the office. It is not easy to sit properly at work all the time and sitting for a long time with wrong postures may cause a series of health problems as time goes by. In addition, monitoring the sitting posture of patients with spinal disease would be beneficial for their recovery. Accordingly, this paper designs and implements a sitting posture recognition system from a flexible array pressure sensor, which is used to acquire pressure distribution map of sitting hips in a real-time manner. Moreover, an improved self-organizing map-based classification algorithm for six kinds of sitting posture recognition is proposed to identify whether the current sitting posture is appropriate. The extensive experimental results verify that the performance of ISOM-based sitting posture recognition algorithm (ISOM-SPR) in short outperforms that of four kinds of traditional algorithms including decision tree-based (DT), K-means-based (KM), back propagation neural network-based (BP), self-organizing map-based (SOM) sitting posture recognition algorithms. Finally, it is proven that the proposed system based on ISOM-SPR algorithm has good robustness and high accuracy.

IoT Device for Sitting Posture Classification Using Artificial Neural Networks

Nowadays, the percentage of time that the population spends sitting has increased substantially due to the use of computers as the main tool for work or leisure and the increase in jobs with a high office workload. As a consequence, it is common to suffer musculoskeletal pain, mainly in the back, which can lead to both temporary and chronic damage. This pain is related to holding a posture during a prolonged period of sitting, usually in front of a computer. This work presents a IoT posture monitoring system while sitting. The system consists of a device equipped with Force Sensitive Resistors (FSR) that, placed on a chair seat, detects the points where the user exerts pressure when sitting. The system is complemented with a Machine Learning model based on Artificial Neural Networks, which was trained to recognize the neutral correct posture as well as the six most frequent postures that involve risk of damage to the locomotor system. In this study, data was collected from 12 participants for each of the seven positions considered, using the developed sensing device. Several neural network models were trained and evaluated in order to improve the classification effectiveness. Hold-Out technique was used to guide the training and evaluation process. The results achieved a mean accuracy of 81% by means of a model consisting of two hidden layers of 128 neurons each. These results demonstrate that is feasible to distinguish different sitting postures using few sensors allocated in the surface of a seat, which implies lower costs and less complexity of the system.

Lower spinal postural variability during laptop-work in subjects with cervicogenic headache compared to healthy controls

Spinal postural variability (SPV) is a prerequisite to prevent musculoskeletal complaints during functional tasks. Our objective was to evaluate SPV in cervicogenic headache (CeH) since CeH is characterized by such complaints. A non-randomized repeated-measure design was applied to compare SPV between 18 participants with reporting CeH aged 29–51 years, and 18 matched controls aged 26–52 years during a 30-min-laptop-task. Habitual spinal postures (degrees) of the cervical, thoracic and lumbar spine were analysed using 3D-Vicon motion analysis. SPV, to express variation in mean habitual spinal posture, was deducted from the postural analysis. Mean SPV of each spinal segment was lower in the CeH-group compared to the control-group. Within the CeH-group, SPV of all except one spinal segment (lower-lumbar) was higher compared to the group’s mean SPV. Within the control-group, SPV was more comparable to the group’s mean SPV. SPV differed between groups. Averaging data resulted in decreased SPV in the CeH-group compared to the control-group during the laptop-task. However, the higher within-group-SPV in the CeH-group compared to the group’s mean SPV accentuated more postural heterogeneity. It should be further determined if addressing individual SPV is a relevant intervention.

Is Neck Posture Subgroup in Late Adolescence a Risk Factor for Persistent Neck Pain in Young Adults? A Prospective Study

OBJECTIVE

The purpose of this study was to determine whether sagittal neck sitting posture subgroup membership in late adolescence was a risk factor for persistent neck pain (PNP) in young adults.

METHODS

There were 686 participants enrolled in the Raine Study at the 17- and 22-year follow-ups. At 17 years of age, posture was measured by photographs, and 4 subgroups of sitting neck posture were determined by cluster analysis. Height and weight were measured, and exercise frequency, depression, and PNP were assessed by questionnaire. At 22 years of age, participants answered questions about neck pain and occupation type. Logistic regression examined if neck posture subgroups at 17 years of age were a risk factor for PNP at 22 years of age, taking into account other factors.

RESULTS

Female sex (odds ratio [OR] = 1.75, 95% CI = 1.16-2.65) and PNP at 17 years of age (OR = 3.78, 95% CI = 2.57-5.57) were associated with PNP at 22 years of age. In females, neck posture subgroup at 17 years of age was a risk factor for PNP at 22 years of age. Compared with the upright subgroup, both the slumped thorax/forward head subgroup groups and the intermediate subgroup had decreased odds for PNP at 22 years of age (OR = 0.24, 95% CI = 0.08-0.76; OR = 0.38, 95% CI = 0.15-0.99, respectively). No association was found in males.

CONCLUSION

After taking into account PNP at 17 years, sitting neck posture at 17 was not a risk factor for PNP at 22 years of age in males, whereas in females, more relaxed postures (slumped thorax/forward head and Intermediate postures) were protective of neck pain compared with upright posture.

IMPACT

Females in late adolescence who sat in slumped thorax/forward head or intermediate posture rather than upright sitting posture had a lower risk of PNP as a young adult. The practice of generic public health messages to sit up straight to prevent neck pain needs rethinking.

Notions of "optimal" posture are loaded with meaning. Perceptions of sitting posture among asymptomatic members of the community

BACKGROUND

Notions of "optimal" posture are widespread in modern society and strongly interconnected with preconceived beliefs.

OBJECTIVES

To quantitatively evaluate spinal posture among members of the community during habitual sitting, and when asked to assume an "optimal" posture.

DESIGN

Observational study.

METHODS

Marker-based kinematic analyses of the head, spine, and pelvis were conducted on 100 individuals. Habitual sitting posture and self-perceived "optimal" posture, and whether participants believed that their habitual sitting reflected an "optimal" posture, were evaluated. The Wilcoxon signed-rank test assessed angular differences between the two postures adopted. Exploratory post-hoc analyses were conducted by using the Mann-Whitney U test to assess differences between genders.

RESULTS

None of the participants stated that their habitual sitting was "optimal". Statistically significant differences were observed in most of the measured angles (p < 0.001) between habitual and self-perceived "optimal" posture. In habitual sitting posture, a significant interaction with gender was found only in the thoracolumbar (p < 0.05) and pelvic (p < 0.001) angles, with small effect sizes. In self-perceived "optimal" posture females were more extended in the head, upper thoracic, lower thoracic, lumbar and pelvic (p < 0.01) regions, than the males.

CONCLUSIONS

A group of young, asymptomatic participants, consistently changed their habitual sitting posture to a more upright posture when asked to assume an "optimal" sitting posture, although the amount of change observed varied between spinal regions. These findings also highlight gender differences in not just habitual sitting posture, but also the degree to which habitual sitting posture is modified when trying to assume an "optimal" sitting posture.

A novel multi-study intervention investigating the short and long term effects of a posture bra on whole body and breast kinematics

BACKGROUND

Poor standing posture has been reported in women with larger breasts, increasing the risk of back pain. Whilst breast reduction surgery can improve posture, conservative measures such as special bras may offer short or long-term relief of symptoms without surgical intervention.

RESEARCH QUESTION

This study aimed to utilise a multi-study intervention to investigate the short and long-term kinematic effects of wearing a posture bra.

METHODS

Study one utilised biomechanics and physiotherapy expertise to modify the design of a prototype bra to improve posture and breast kinematics; resulting in a second-generation posture bra. To test this bra, 24 females were randomly assigned to control and intervention groups. The control group wore their everyday bra; the intervention group wore the generation 2 posture bra in place of their everyday bra for three months. Pre and post intervention, posture (spine curvature, scapula position, whole body alignment) and breast kinematics were assessed during sitting, standing and walking. Short-term effects of the posture bra were compared to an everyday bra and no bra (study two), whilst the long-term effects were compared using the no bra condition (study three).

RESULTS

Biomechanical intervention improved posture and breast kinematics in a prototype posture bra resulting in a second-generation prototype. Pre-intervention, the generation 2 posture bra significantly improved scapula retraction by 6° during both sitting and standing, but also increased deviation of whole body alignment compared to everyday bra and no bra conditions. During walking the posture bra reduced breast motion by 17 % compared to the everyday bra. Following the three-month wearer intervention, scapula depression significantly improved in the intervention group.

SIGNIFICANCE

A biomechanically informed posture bra was able to effectively support the breasts and improve scapula position without compromising spinal curvature, reducing the risk of musculoskeletal pain associated with poor posture.

Comprehensive corrective exercise program improves alignment, muscle activation and movement pattern of men with upper crossed syndrome: randomized controlled trial

Upper crossed syndrome (UCS) refers to the altered muscle activations and movement patterns in scapulae along with some abnormal alignment in the upper quarter, which may contribute to the dysfunction of the cervicothoracic and glenohumeral joints. The present study aimed to investigate the effectiveness of a comprehensive corrective exercise program (CCEP) and subsequent detraining on alignment, muscle activation, and movement pattern in men with the UCS. This randomized controlled trial included 24 men. The intervention group conducted CCEP (8 weeks), followed by four weeks of detraining and the control group maintained normal daily activities. Electromyography of selected muscles, scapular dyskinesis test, head, shoulder, and thoracic spine angle were measured at baseline, post-test, and follow-up. There were significant differences for Group x time interaction and also for within-group from pre-test to post-test and follow-up in all outcomes. Also, significant differences were observed in three outcomes at post-test and follow-up between the CCEP and control group in favor of the CCEP. In Conclusion, the present study demonstrates that the CCEP for individuals with UCS is feasible and effective, improving muscle activation imbalance, movement patterns, and alignment. Importantly, these improvements were maintained after four weeks of detraining, suggesting lasting neuromuscular re-training adaptations.

Reliability of the Soleus H-Reflex in Different Sitting Postures

The Soleus (SOL) Hoffmann reflex (H-reflex) is commonly recorded in sitting position. However, the reliability of recording is unknown. We assessed the reliability of SOL H-reflex amplitude measurements across multiple traces and sessions during erect, slumped, and slouched sitting postures using the generalizability theory. Five traces of the SOL H-reflex maximum amplitude (H_max) were recorded from 10 healthy participants during erect, slumped, and slouched sitting postures in two sessions. A decision study analysis was then conducted to calculate the reliability coefficients of the H_max for five traces and two sessions and to mathematically calculate the coefficients for seven and ten traces, and one and three sessions in the three sitting postures. For five traces and two sessions, the results showed reliability coefficients between 0.970 and 0.971, 0.980 and 0.979, and equal to 0.943 for erect, slumped, and slouched sitting, respectively. Averaging five traces of the H_max in a single recording session was sufficient to obtain acceptable reliability in the three sitting postures (reliability range, 0.892–0.988). It was concluded that the SOL H_max can be recorded during erect, slumped, and slouched sitting postures with adequate reliability.

Effect of Using an 8-Figure Shoulder Brace on Posture and Muscle Activities during the Performance of Dental Hygiene Procedures

The incidence of work-related musculoskeletal disorders (MSDs) among dental workers has been increasing. Many ergonomic devices and accessories have been introduced. The aim of this study was to investigate the effects of an 8-figure shoulder brace on posture-related muscle activities in dental hygiene practitioners during scaling procedures. In this study, 33 participants (age: 21.9 ± 2.1 years, height: 162.0 ± 6.0 cm, weight: 55.8 ± 9.0 kg, body mass index: 21.2 ± 2.4 kg/m²) performed the scaling procedure with and without the 8-figure shoulder brace in a randomized order. The normalized electromyography activity in the amplitude probability distribution function and joint angles (cervical, thoracic, lumbar, and shoulder joints) were simultaneously recorded during scaling. A paired t test was used to compare the differences in muscle kinematics, with the alpha level set at 0.05. The dental hygienists who wore the 8-figure shoulder brace during scaling showed thoracic and lumbar extension, improved sitting postures, and reduced shoulder joint abduction. However, we also observed an unintended increase in internal rotation. Use of the 8-figure shoulder brace could prevent work-related MSDs in lumbar and thoracic regions by reducing the effort exerted by the upper trapezius and deltoid muscles, despite the increased muscular effort of the cervical erector spinae.

Exercise interventions to improve postural malalignments in head, neck, and trunk among adolescents, adults, and older people: systematic review of randomized controlled trials

Despite the widespread use of postural correction in exercise interventions, limited experimental evidence exists for its effectiveness. The present study aimed to systematically review the literature on the efficacy of exercise interventions in improving postural malalignment in head, neck, and trunk. A systematic review was performed by screening four scientific databases (MEDLINE, Web of Science, EBSCO, and Cochrane database) for published randomized controlled trials (RCTs) in English from 1996–2019. The review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement guidelines. Two researchers independently performed study screening, extracting data and assessing the risk of bias for each included study using the Cochrane Collaboration tool for evaluating the risk of bias. A total of 22 RCTs comprising 1,209 participants were identified for inclusion in the review. There was a high risk of bias across most of the included studies (12 studies). Only two studies were classified as low risk of bias, and eight studies were classified as moderate risk of bias. The intervention duration ranged from 2 to 13 weeks, frequency from 2 to 4 days per week, and duration of each session between 15 to 60 min. The insufficiency and quality of included studies did not allow an integrated assessment of the efficacy of exercise interventions on postural malalignments; however, the positive effects noticed in most of the studies indicate some advantages but underscores the necessity of adequately designed RCTs in this field.

The effectiveness of a comprehensive corrective exercises program and subsequent detraining on alignment, muscle activation, and movement pattern in men with upper crossed syndrome: protocol for a parallel-group randomized controlled trial

Background

Upper crossed syndrome (UCS) refers to specific altered muscle activation and changed movement patterns along with some postural deviations in the upper quarter of the body. This syndrome might contribute to the dysfunction of the cervicothoracic and glenohumeral joints.

Objectives

The present study will aim to investigate the effectiveness of a comprehensive corrective exercises program (CCEP) and subsequent detraining on alignment, muscle activation and movement pattern in men with UCS.

Methods/design

This is a parallel-group randomized controlled trial. Participants will be 22 men aged 18 to 28 years who are suffering from UCS. Participants in the intervention group will conduct CCEP (three times a week for 8 weeks), followed by 4 weeks of detraining. The control group will do their daily activities. Participants will be randomized (1:1) into the intervention or the control group. The primary outcome will be upper trapezius activations. Secondary outcomes consist of electromyography of middle and lower trapezius and serratus anterior muscles, scapular dyskinesis test, forward head and shoulder angles, thoracic kyphosis angle, and neck flexion pattern test.

Discussion

We propose to evaluate the effectiveness of a randomized controlled trial of a CCEP in men with UCS on their alignment, selected muscle activations, and relevant movement patterns. Results from our trial may provide new insights into the effects of exercise not only on the alignment but also on muscle activation and movement patterns that are important outcomes for people with postural malalignments and, if successful, could assist therapists in evidence-based clinical decision-making.

Trial registration

Iranian Registry of Clinical Trials, IRCT20181004041232N1. Registered on 26 October 2018.

Electronic Skin Wearable Sensors for Detecting Lumbar-Pelvic Movements

Background: A nanomaterial-based electronic-skin (E-Skin) wearable sensor has been successfully used for detecting and measuring body movements such as finger movement and foot pressure. The ultrathin and highly sensitive characteristics of E-Skin sensor make it a suitable alternative for continuously out-of-hospital lumbar–pelvic movement (LPM) monitoring. Monitoring these movements can help medical experts better understand individuals’ low back pain experience. However, there is a lack of prior studies in this research area. Therefore, this paper explores the potential of E-Skin sensors to detect and measure the anatomical angles of lumbar–pelvic movements by building a linear relationship model to compare its performance to clinically validated inertial measurement unit (IMU)-based sensing system (ViMove). Methods: The paper first presents a review and classification of existing wireless sensing technologies for monitoring of body movements, and then it describes a series of experiments performed with E-Skin sensors for detecting five standard LPMs including flexion, extension, pelvic tilt, lateral flexion, and rotation, and measure their anatomical angles. The outputs of both E-Skin and ViMove sensors were recorded during each experiment and further analysed to build the comparative models to evaluate the performance of detecting and measuring LPMs. Results: E-Skin sensor outputs showed a persistently repeating pattern for each movement. Due to the ability to sense minor skin deformation by E-skin sensor, its reaction time in detecting lumbar–pelvic movement is quicker than ViMove by ~1 s. Conclusions: E-Skin sensors offer new capabilities for detecting and measuring lumbar–pelvic movements. They have lower cost compared to commercially available IMU-based systems and their non-invasive highly stretchable characteristic makes them more comfortable for long-term use. These features make them a suitable sensing technology for developing continuous, out-of-hospital real-time monitoring and management systems for individuals with low back pain.

Development of wearable posture monitoring system for dynamic assessment of sitting posture

There have been increasing cases of people seeking treatment for neck and back pain. The most common cause of neck and back pain is due to long-term poor sitting posture. The most common poor sitting posture cases are humpback, and head and neck being too far forward. It is easy to cause neck and back pain and other symptoms. Therefore, the development of wearable posture monitoring system for dynamic assessment of sitting posture becomes both helpful and necessary. In addition to recording the wearer's posture when sitting with quantitative assessment, it is needed to execute real-time action feedback for correctness of posture, in order to reduce neck and back pain due to long-term poor sitting posture. This study completed an instant recording and dynamic assessment of position measurement and feedback system. The system consists of a number of dynamic measurement units that can describe the posture trajectory, which integrates three-axis gyro meter, three-axis accelerometer, and magnetometer in order to measure the dynamic tracking. In the reliability analysis experiment, angle measurement error is less than 2%. The correlation coefficient between correlation analysis and Motion Analysis (MA) is 0.97. It is shown that the motion trajectory of this system is highly correlated with MA. In the feasibility test of sitting position detection, it is possible to detect the sitting position from the basic action of the walking, standing, sitting and lying down, and the sensitivity reaches 95.84%. In the assessment of the sitting position, the information published by the Canadian Centre for Occupational Health and Safety was used, as well as the recommendations of professional physicians as a basis for evaluating the threshold of the sitting measurement parameters and immediately feedback to the subjects. The system developed in this study can be helpful to reduce neck and back pain due to long-term poor sitting posture.

Low back pain and its relationship with sitting behaviour among sedentary office workers

The relationships between sedentary lifestyle, sitting behaviour, and low back pain (LBP) remain controversial. In this study, we investigated the relationship between back pain and occupational sitting habits in 64 call-centre employees. A textile pressure mat was used to evaluate and parameterise sitting behaviour over a total of 400 h, while pain questionnaires evaluated acute and chronic LBP. Seventy-five percent of the participants reported some level of either chronic or acute back pain. Individuals with chronic LBP demonstrated a possible trend (t-test not significant) towards more static sitting behaviour compared to their pain-free counterparts. Furthermore, a greater association was found between sitting behaviour and chronic LBP than for acute pain/disability, which is plausibly due to a greater awareness of pain-free sitting positions in individuals with chronic pain compared to those affected by acute pain.

Can a smart chair improve the sitting behavior of office workers?

Prolonged sitting can cause health problems and musculoskeletal discomfort. There is a need for objective and non-obstructive means of measuring sitting behavior. A 'smart' office chair can monitor sitting behavior and provide tactile feedback, aiming to improve sitting behavior. This study aimed to investigate the effect of the feedback signal on sitting behavior and musculoskeletal discomfort. In a 12-week prospective cohort study (ABCB design) among office workers (n = 45) was measured sitting duration and posture, feedback signals and musculoskeletal discomfort. Between the study phases, small changes were observed in mean sitting duration, posture and discomfort. After turning off the feedback signal, a slight increase in sitting duration was observed (10 min, p = 0.04), a slight decrease in optimally supported posture (2.8%, p < 0.01), and musculoskeletal discomfort (0.8, p < 0.01) was observed. We conclude that the 'smart' chair is able to monitor the sitting behavior, the feedback signal, however, led to small or insignificant changes.

Use of Integrative Medicine in the United States Military Health System

Integrative medicine (IM) is a model of care which uses both conventional and nonconventional therapies in a "whole person" approach to achieve optimum mental, physical, emotional, spiritual, and environmental health, and is increasingly popular among patients and providers seeking to relieve chronic or multifactorial conditions. The US Department of Defense (DoD) shows particular interest in and usage of IM for managing chronic conditions including the signature "polytrauma triad" of chronic pain, traumatic brain injury (TBI), and posttraumatic stress disorder (PTSD) among its beneficiaries in the Military Health System (MHS). These modalities range from conventional nondrug, nonsurgical options such as cognitive-behavioral therapy to nonconventional options such as acupuncture, chiropractic, and mind-body techniques. These are of particular interest for their potential to relieve symptoms without relying on opiates, which impair performance and show high potential for abuse while often failing to provide full relief. This review describes the use of IM in the MHS, including definitions of the model, common therapies and potential for use, and controversy surrounding the practice. More research is needed to build a comprehensive usage analysis, which in turn will inform sound clinical and financial practice for the MHS and its beneficiaries.

Active self-correction of spinal posture in pain-free women in response to the command "straighten your back"

Evidence is limited regarding the regional changes in spinal posture after self-correction. The aim of the present study was to evaluate whether active self-correction improved standing and sitting spinal posture. Photogrammetry was used to assess regional spinal curvatures and vertical global spine orientation (GSO) in 42 asymptotic women aged 20-24 years. Upper thoracic spine angle and GSO increased in response to self-correction, while the thoracolumbar and lumbosacral angles decreased. Self-correction in the standing position resulted in decreased inclination of the upper thoracic and thoracolumbar spinal angles. Correction of sitting posture reduced the angle of the upper thoracic spine and GSO. The effects of active self-correction on spinal curvature and GSO were different for the standing versus sitting position; the greatest effects of active correction were noted in the thoracic spine. Balanced and lordotic postures were most prevalent in the habitual and actively self-corrected standing positions, whereas the kyphotic posture was most prevalent in the habitual sitting position, indicative that self-correction back posture in the standing position could be an important health-related daily activity, especially during prolonged sitting.