Lumbar posture and muscular activity while sitting during office work

Effect of two dynamic seat cushions on postural shift, trunk muscle activation and spinal discomfort in office workers

We investigated the effect of two dynamic seat cushions on postural shift, trunk muscle activation and spinal discomfort. In this repeated-measures study, 30 healthy office workers were randomly assigned to a sequence of three conditions: sitting on a dynamic seat cushion-A, cushion-B and control (no seat cushion). The two dynamic seat cushions had different inflation levels. Participants typed a standard text for an hour and were monitored for postural shift by using a seat pressure mat, transversus abdominis/internal oblique and lumbar multifidus muscles activity by using surface EMG, spinal discomfort by using Borg's CR-10 scale. Two-way repeated ANOVAs showed no statistically significant interaction effects between condition and time on postural shift and muscle activation. Post hoc Bonferroni tests showed that postural shifts and lumbar multifidus activation during sitting on cushion-A were significantly higher (p < 0.01) than in the control and cushion-B conditions. Both cushions reduced spinal discomfort, compared to the control condition (p < 0.05).

Lumbar multifidus layers stiffness at L5-S1 level in prone and sitting posture measured by shear wave elastography

BACKGROUND

Multifidus is an important lumbar muscle with distinct superficial and deep fibers responsible for torque production and stabilization, respectively. Its mechanical properties change when transitioning from lying to sitting positions, necessitating enhanced stability. It holds crucial clinical relevance to assess these layers separately, especially in the sitting posture, which demands increased neuromuscular control compared to the prone position.

OBJECTIVE

To compare lumbar multifidus stiffness in lying versus sitting postures, analyzing both superficial and deep layers.

METHODS

Supersonic Shear Imaging captured elastographic images from 26 asymptomatic volunteers in prone and seated positions.

RESULTS

Left multifidus shear modulus in lying: 5.98 ± 1.80/7.96 ± 1.59 kPa (deep/superficial) and sitting: 12.58 ± 4.22/16.04 ± 6.65 kPa. Right side lying: 6.08 ± 1.97/7.80 ± 1.76 kPa and sitting: 13.25 ± 4.61/17.95 ± 7.12 kPa. No side differences (lying p= 0.99, sitting p= 0.43). However, significant inter-postural differences occurred.

CONCLUSION

Lumbar multifidus exhibits increased stiffness in sitting, both layers affected, with superior stiffness in superficial versus deep fibers. Applying these findings could enhance assessing multifidus stiffness changes, for classifying tension-induced low back pain stages.

Active workstations: A literature review on workplace sitting

The purpose of this paper is to further understand current literature on prolonged sitting, sitting posture and active sitting solutions. This paper is divided into three sections: The first section (Part I) is a comprehensive overview of the literature on how a static prolonged seated posture can affect: spinal health, trunk posture, contact pressure/discomfort development and vascular issues. The second section (Part II) reviews and qualitatively compares the four working postures recognized in ANSI/HFES 100-2007: reclined sitting, upright sitting, declined sitting and standing. The final section (Part III) is a summary of research on active chairs that revolves around the two types of movement patterns: 1- sustaining continual movement over a range of postures, occasionally reaching neutral lordosis, and 2- maintaining high frequency and duration of daily light contractile activity in the legs (or lower limbs).

Improving wheelchair user sitting posture to alleviate lumbar fatigue: a study utilizing sEMG and pressure sensors

Background

The wheelchair is a widely used rehabilitation device, which is indispensable for people with limited mobility. In the process of using a wheelchair, they often face the situation of sitting for a long time, which is easy to cause fatigue of the waist muscles of the user. Therefore, this paper hopes to provide more scientific guidance and suggestions for the daily use of wheelchairs by studying the relationship between the development of muscle fatigue and sitting posture.

Methods

First, we collected surface Electromyography (sEMG) of human vertical spine muscle and analyzed it in the frequency domain. The obtained Mean Power Frequency (MPF) was used as the dependent variable. Then, the pose information of the human body, including the percentage of pressure points, span, and center of mass as independent variables, was collected by the array of thin film pressure sensors, and analyzed by a multivariate nonlinear regression model.

Results

When the centroid row coordinate of the cushion pressure point is about 16(range, 7.7-16.9), the cushion pressure area percentage is about 80%(range, 70.8%-89.7%), and the cushion pressure span range is about 27(range, 25-31), the backrest pressure point centroid row coordinate is about 15(range, 9.1-18.2), the backrest pressure area percentage is about 35%(range, 11.8%-38.7%), and the backrest pressure span range is about 16(range, 9-22). At this time, the MPF value of the subjects decreased by a small percentage, and the fatigue development of the muscles was slower. In addition, the pressure area percentage at the seat cushion is a more sensitive independent variable, too large or too small pressure area percentage will easily cause lumbar muscle fatigue.

Conclusion

The results show that people should sit in the middle and back of the seat cushion when riding the wheelchair, so that the Angle of the hip joint can be in a natural state, and the thigh should fully contact the seat cushion to avoid the weight of the body concentrated on the buttocks; The back should be fully in contact with the back of the wheelchair to reduce the burden on the waist, and the spine posture can be adjusted appropriately according to personal habits, but it is necessary to avoid maintaining a chest sitting position for a long time, which will cause the lumbar spine to be in an unnatural physiological Angle and easily lead to fatigue of the waist muscles.

Prevalence of adolescent idiopathic scoliosis in Shijiazhuang, Hebei, China: a cross-sectional study

PURPOSE

This study is a large-scale screening supported by government departments to investigate the prevalence of scoliosis in Shijiazhuang.

METHODS

In this cross-sectional study, all students underwent body posture evaluation and the Adam's forward flexure test to examine the back, and also underwent radiographic evaluation when scoliosis was suspected.

RESULTS

In total, 181,935 students participated in the research, of which 289 students were diagnosed with scoliosis, with a prevalence of 2.5%, significantly higher in female (3.01%) than in male children (1.63%) (P < 0.001). Most of the patients (79.5%) had a Cobb angle from 10° to 19°.The mean Cobb angle of scoliosis was positively associated with age. The prevalence of a single curve (75.4%) was significantly higher than double curves (23.2%) and triple curves (1.38%). The percentage of scoliosis in which the thoracolumbar segment was involved (46.4%) was significantly higher than that of the single thoracic scoliosis (31.8%) and single lumbar scoliosis (21.8%).

CONCLUSIONS

The prevalence of adolescent idiopathic scoliosis in XXX was high (2.50%). It is necessary to strengthen the education of adolescent scoliosis, and improve the awareness and attention of social to scoliosis.

LEVEL OF EVIDENCE

IV.

Effect of office chair design features on lumbar spine posture, muscle activity and perceived pain during prolonged sitting

Chair design features are typically compared using multiple seats, which can lead to confounding effects. Using a single chair, configurable to four designs (control, lumbar support, seat pan tilt and scapular relief), we investigated the effect of chair design on spine posture and movement, muscle activity and perceived pain in a sample of 31 asymptomatic adults. A total of 39% of the population were classified as pain developers, having significantly higher peak pain levels across most body regions. The lumbar support and seat pan tilt condition resulted in more neutral spine and pelvic postures. Greater muscle activity was found in the seat pan condition and non-pain developers displayed lower spine muscle activation levels overall. Despite some improvements in spine posture, sitting-induced pain was present in the study sample at similar proportions to those reported previously. Future studies may consider investigating interventions targeted to sitting-induced pain developers as opposed to the general population. Practitioner summary: Four office chair configurations were tested. The lumbar support and seat pan tilt conditions resulted in the most neutral back posture but did not mitigate the clinically significant levels of sitting-induced pain experienced by a large portion of the tested sample. Future work should target interventions to these individuals.

Significance of Lower Body Postures in Chair Design

OBJECTIVE

This study examined a system-level perspective to investigate the changes in the whole trunk and head postures while sitting with various lower extremity postures.

BACKGROUND

Sitting biomechanics has focused mainly on the lumbar region only, whereas the anatomy literature has suggested various links from the head and lower extremity.

METHOD

Seventeen male participants were seated in six lower extremity postures, and the trunk kinematics and muscle activity measures were captured for 5 s.

RESULTS

Changes in the trunk-thigh angle and the knee angle affected the trunk and head postures and muscle recruitment patterns significantly, indicating significant interactions between the lower extremity and trunk while sitting. Specifically, the larger trunk-thigh angle (T135°) showed more neutral lumbar lordosis (4.0° on average), smaller pelvic flexion (1.8°), smaller head flexion (3.3°), and a less rounded shoulder (1.7°) than the smaller one (T90°). The smaller knee angle (K45°) revealed a more neutral lumbar lordosis (6.9°), smaller pelvic flexion (9.2°), smaller head flexion (2.6°), and less rounded shoulder (2.4°) than the larger condition (K180°). The more neutral posture suggested by the kinematic measures confirmed significantly less muscular recruitment in the trunk extensors, except for a significant antagonistic co-contraction.

CONCLUSION

The lower and upper back postures were more neutral, and back muscle recruitment was lower with a larger trunk-thigh angle and a smaller knee angle, but at the cost of antagonistic co-contraction.

APPLICATION

The costs and benefits of each lower extremity posture can be used to design an ergonomic chair and develop an improved sitting strategy.

Increasing movement during office work at sit-stand workstations: A novel seating device to facilitate transitions

A novel active office chair (Movably Pro) was designed to facilitate frequent sit-stand movement 1) through auditory and tactile prompts and 2) with minimal-to-no work surface adjustment when transitioning. The purpose of this study was to compare lumbopelvic kinematics, discomfort, and task performance between the novel chair and traditional sitting/standing. Sixteen participants completed three separate 2-h sedentary exposures. Although participants transitioned every 3 min between sitting and standing with the novel chair, productivity was not affected. When standing in the novel chair, the lumbopelvic angles fell in between traditional sitting and standing (p < 0.01). Movement and/or postural changes that occurred with the novel chair reduced low back and leg discomfort for pain developers (PDs) (p < 0.01). All participants classified as PDs in traditional standing were non-PDs with the novel chair. This intervention was effective in reducing sedentary time without the time loss associated with desk movement.

Effects of Lumbar Stabilization Exercises on Isokinetic Strength and Muscle Tension in Sedentary Men

Lumbar stabilization exercises (LSE) lead to high levels of erector spinae muscle (ESM) activation, which has a positive effect on improving physical function. The purpose of this study is to identify factors explaining changes in muscle strength after 7 weeks of LSE and to evaluate changes in stiffness and contraction of the ESM. All participants (male: n = 42, age = 28.26 ± 10.97) were assessed for 60°/s isokinetic extensor muscle strength and tension using a tensiomyography (TMG) and isokinetic device before and after LSE. Maximum displacement (Dm) and average velocity up to 90% Dm (Vc 90) were significantly different before and after LSE. Additionally, participants’ 60°/s isokinetic extensor strength was significantly higher after exercise. A regression analysis was conducted to test the explanatory power of the variables, and positive results were obtained in the increase in extensor strength before and after Vc 90 and LSE. Furthermore, statistical significance was set at p < 0.05. After LSE, the increase in 60°/s isokinetic extensor strength and ESM’s Dm and Vc 90 can be interpreted as positive changes post-exercise in endurance muscles with a higher percentage of type I fibers. Our results can contribute to predicting the long-term exercise effect in sedentary workers and developing an individualized strategic exercise program.

Factors associated with the incidence and worsening of back pain during the first wave of COVID-19 in Brazil

Abstract The article aims to estimate the incidence and worsening of back pain (BP) during the first wave of COVID-19 in Brazil, as well as to investigate demographic, socioeconomic factors and associated changes in living conditions. ConVid - Behavior Research, applied between April and May 2020, was used as data source. The number and distribution of respondents who developed BP and those who had a worsening of the preexisting problem, their 95% confidence intervals and Pearson’s Chi-square test were estimated. The odds ratio of developing BP or worsening a preexisting problem was also estimated using multiple logistic regression models. Pre-existing BP was reported by 33.9% (95%CI 32.5-35.3) of respondents and more than half (54.4%; 95%CI 51.9-56.9) had worsened. The cumulative incidence of BP in the first wave of the pandemic was 40.9% (95%CI 39.2-42.7). Being a woman, the perceived increase in housework and the frequent feeling of sadness or depression were associated with both outcomes. Socioeconomic factors were not associated with any of outcome. The high incidence and worsening of BP during the first wave reveal the need for studies in more recent periods, given the long duration of the pandemic.

Factors associated with the incidence and worsening of back pain during the first wave of COVID-19 in Brazil

The article aims to estimate the incidence and worsening of back pain (BP) during the first wave of COVID-19 in Brazil, as well as to investigate demographic, socioeconomic factors and associated changes in living conditions. ConVid - Behavior Research, applied between April and May 2020, was used as data source. The number and distribution of respondents who developed BP and those who had a worsening of the preexisting problem, their 95% confidence intervals and Pearson's Chi-square test were estimated. The odds ratio of developing BP or worsening a preexisting problem was also estimated using multiple logistic regression models. Pre-existing BP was reported by 33.9% (95%CI 32.5-35.3) of respondents and more than half (54.4%; 95%CI 51.9-56.9) had worsened. The cumulative incidence of BP in the first wave of the pandemic was 40.9% (95%CI 39.2-42.7). Being a woman, the perceived increase in housework and the frequent feeling of sadness or depression were associated with both outcomes. Socioeconomic factors were not associated with any of outcome. The high incidence and worsening of BP during the first wave reveal the need for studies in more recent periods, given the long duration of the pandemic.

Remote work and back pain during the COVID-19 pandemic in adults and older population in South Brazil

This article aims to investigate the association between remote work and Back Pain during the COVID-19 pandemic, and to analyze this relationship according to the body mass index. Population-based, cross-sectional study carried in two cities in southern Brazil, in individuals aged 18 years and over. Data were collected through household interviews from October to January 2020/21. Outcomes: back pain (cervical, thoracic, lumbar/acute, chronic) and pain intensity. Exposure variable: remote work. For the analyses, Poisson regression with robust adjustment for variance was used, stratified by BMI (eutrophic vs overweight/obese), and restricted to those who had worked in the past month. 1,016 had worked during the pandemic, average 42 years old (SD = 14), varying from 18 to 93 years. Remote work was performed by 7.7% of the individuals. Prevalence of back pain: 25.6% (95%CI: 19.5 to 31.7%). Overweight/obese remote workers felt pain acute cervical pain PR = 2.82 (95%CI: 1.15 to 6.92); chronic low back PR = 1.85 (95%CI: 1.04 to 3.29); acute thoracic PR = 1.81(95%CI: 3.76 to 8.68) compared to those who did not work. About one in four remote workers reported back pain during of the COVID-19 pandemic. BMI proved to be an important moderator between outcomes and exposure variable.

Work from home-related musculoskeletal pain during the COVID-19 pandemic: A rapid review

Objective

This rapid review explores the prevalence of musculoskeletal pain symptoms associated with work from home conditions during the COVID-19 pandemic.

Methods

We conducted a rapid review across three databases (i.e., PubMed, Medline, and CINAHL) for observational studies that report on the musculoskeletal functions among individuals placed in a work from home setup due to the COVID-19 pandemic, published between December 2019-August 2021. Two independent review authors searched, appraised, and extracted data from the articles included in the final review. A descriptive approach was used to synthesize the narrative evidence.

Results

Forty-four articles were initially identified. A total of six (n = 6) studies met the full inclusion criteria and were included. Among them, there were five cross-sectional studies and one case-control study. The highest prevalence reported were neck pain (20.3-76.9%), low back pain (19.5-74.1%), and shoulder pain (3.0-72.9%). The most common instrument used was the Nordic Musculoskeletal Questionnaire. One of the common professions that report musculoskeletal pain symptoms associated with work from home conditions were individuals working in the academic sector.

Conclusion

The increased prevalence of musculoskeletal pain symptoms associated with work from home conditions during the COVID-19 pandemic is a concern that should be addressed to prevent negative neuromusculoskeletal outcomes.

Systematic review registration

This review is in the Open Science Framework registry (osf.io/vxs4w) and the PROSPERO database (CRD42021266097).

Implications for practice

•A system in the workplace should be developed for the early detection of musculoskeletal pain.•Apart from standard occupational safety and proper ergonomic, sustainable policies and programs that address the mental health issues of employees should also be addressed.•Programs addressing musculoskeletal pain should be available online for employees to address accessibility and ubiquity.

Effects of Postural Shifting Frequency on Perceived Musculoskeletal Discomfort During 1-Hour Sitting in Office Workers

OBJECTIVE

The purpose of this study was to evaluate the effects of postural shifting frequency on perceived musculoskeletal discomfort during 1 hour of sitting in healthy office workers.

METHODS

An experimental study comparing 3 different postural shifting frequencies was conducted on 60 healthy office workers who were asked to sit for an hour. The effects of 3 postural shifts (ie, 10, 20, and 30 times/h) on discomfort, measured by Borg's CR-10 scale, were compared. A seat pressure mat was used to confirm an individual's postural shift.

RESULTS

Postural shifting frequency of 10 to 30 times/h had significant effects on perceived discomfort in the neck, shoulder, and upper and lower back during 1-hour sitting. At the neck and shoulder, a postural shifting frequency of 30 times/h significantly reduced perceived discomfort compared to a postural shifting frequency of 10 times/h during 1-hour sitting. At the upper and lower back, a postural shifting frequency of 20 to 30 times/h significantly reduced perceived discomfort compared to a postural shifting frequency of 10 times/h.

CONCLUSION

Postural shifts of 30 times/h provided buffering effects on perceived musculoskeletal discomfort at the neck, shoulder, and upper and lower back.

Short-term impact of COVID-19 pandemic on low back pain: data from the PAMPA Cohort, Brazil

BACKGROUND

To evaluate the short-term impact of COVID-19 pandemic on low back pain (LBP) outcomes in southern Brazil.

METHODS

Data from the PAMPA Cohort were analyzed. Adults were recruited between June and July 2020 in the Rio Grande do Sul state using online-based strategies. Participants responded a self-reported, online questionnaire on LBP with two timepoints: before (retrospectively) and during COVID-19 pandemic. We assessed LBP experience, LBP-related activity limitation (no/yes), and LBP intensity (0 to 10 [strongest pain]).

RESULTS

From a total sample of 2,321 respondents (mean age: 37.6 ± 13.5; 75.4% women), the prevalence of LBP did not change significantly from before (74.7% [95%CI 72.3; 76.9]) to the first months of pandemic (74.2% [95%CI 71.9; 76.3]). However, an increased pain levels (β: 0.40; 95%CI 0.22; 0.58) and a higher likelihood for activity limitation due to LBP was observed (PR 1.14; 95%CI 1.01; 1.29). Longitudinal analyzes showed that age, gender, BMI, chronic diseases, physical activity, and anxiety and depression symptoms, were associated with LBP in the first pandemic months.

CONCLUSION

Although the prevalence of LBP did not change at the first months of COVID-19 pandemic, LBP-induced impairment in daily activities and pain intensity was higher when compared to before the pandemic.

The effect of lumbar spinal manipulation on biomechanical factors and perceived transient pain during prolonged sitting: a laboratory-controlled cross-sectional study

BACKGROUND

Spinal manipulation has been shown to affect muscle activity, posture, and pain. To date, no studies have examined the effect of manipulation on biomechanical factors during sitting. Therefore, the purpose of this study was to investigate the immediate effect of lumbar spinal manipulation on trunk muscle activation, spine posture and movements, and perceived ratings of transient pain in asymptomatic adults during prolonged office sitting.

METHODS

Twenty healthy adults were recruited for a single laboratory session that included a standardized office sitting/data entry protocol (120 min total, 3 blocks of 40 min). Data were collected between July and August 2012. The first block (baseline) was immediately followed by two experimental blocks. Prior to the start of each experimental block, participants were transferred to a therapy plinth and placed side lying (right side down), and a random presentation of either a control or high velocity low amplitude thrust directed at L4/L5 was delivered. Continuous measures of muscle activity, spine posture, and spine movements were recorded throughout the sitting trials. Perceived transient pain was measured by visual analogue scale at 10-min intervals (including immediately before and after the randomized maneuvers).

RESULTS

There were no significant differences in spine or pelvic posture or perceived back pain following either the manipulation or control maneuvers. Significantly reduced muscle activity and increased shifts of the lumbar spine angle were identified in the block following manipulation compared to both baseline and post control blocks.

CONCLUSIONS

Spinal manipulation does not appear to have an immediate impact on spine or pelvic posture in healthy adults but does appear to reduce muscle activity and increase spine movement during sitting. Future work should replicate this study with a larger population in a field setting. It may be worthwhile to explore the implication of reduced muscle activation and increased spine movements during prolonged sitting for office workers that receive manipulations or mobilizations during their workday.

Low Back Pain Prevalence among Distance Learning Students

Background: Low back pain as a symptom affects many individuals around the globe regardless of their economic status or sociodemographic characteristics. During the 2019 COVID-19 pandemic, students found themselves obligated to sit down for long periods of time. The aim of this current study is to investigate the impact of these prolonged periods of sitting down in front of computers on developing a new episode of low back pain. Methods and Materials: This research adopted an observational cross-section study design. Students who are currently enrolled or had experienced distance learning classes in the last 6 months were eligible to participate. An online-based questionnaire was developed by the investigators through reviewing the literature with relevant objectives. McNemar’s test was used to compare certain variables between two periods before and during online distance learning. We used paired t-tests to compare pain intensity before, during, and after online learning, while a chi-square test was used to investigate correlations between factors influencing low back pain. Results: A total of 84 students participated in the study—46 (54.8%) females and 38 (45.2%) males. Before online distance learning, only 42.9% of participants reported low back pain, while only 20% had a back injury. The mean pain scores before, during, and after online distance learning were (2.85 ± 2.16, 4.79 ± 2.6, and 4.76 ± 2.7), respectively. The pain scores before online learning were significantly lower than pain scores during and after online distance learning (p < 0.05), respectively. Conclusion: The study findings suggested that low back pain prevalence increased among students during the COVID-19 pandemic. Future research should study participants’ behavior during the online learning and assess the long-run impact of distance learning among high-school and undergraduate students.

Effects of workstation adjustment to reduce postural exposure and perceived discomfort among office workers - A cluster randomized controlled trial

This study aimed to evaluate the effects of workstation adjustment to reduce postural exposure and perceived discomfort among office workers in a cluster randomized controlled trial. Experimental (EG, n = 31) and control groups (CG, n = 30) were compared before (pre-intervention), immediately (post-intervention), and 3 months after (follow up) the intervention. EG received workstation adjustments and CG did not received the intervention. Postural exposure of head, upper back and upper arms was objectively measured by inclinometers. Overall level of perceived discomfort for the whole body was evaluated using a visual analogue scale (0-100 mm). EG showed a statistically significant reduction on the head (pre: 10.1°, SD 5.7°; post: 6.6°, SD 4.7°) and upper back flexion (pre: 15.4°, SD 10.7°; post: 10.4°, SD 8.4°) from pre to post-intervention. EG also showed a statistically significant reduction from pre (50.7°, SD 9.5°) to post-intervention (42.1°, SD 7.6°) and from pre to follow up (41.6°, SD 6.5°) on upper arm elevation. CG did not show any difference between evaluations. Perceived discomfort increased 7.2 (SD 2.0) mm in CG and decreased 22.1 (SD 2.2) mm in EG between pre and post intervention. The variation between pre intervention and follow up was 4.5 (SD 1.2) mm increase for the CG and 24.1 (SD 1.5) mm of reduction for the EG (P < 0.01). There was no significant difference for the post intervention and follow up for both groups (P > 0.05). The results show evidence of the workstation adjustment to reduce postural exposure and perceived discomfort among office workers.

Can the Borg CR-10 scale for neck and low back discomfort predict future neck and low back pain among high-risk office workers?

Purpose

Perceived discomfort could indicate an early sign of pain, for example, as a result of a biomechanical load on the musculoskeletal system. Assessing discomfort can, therefore, help to identify workers at increased risk of musculoskeletal disorders for targeted intervention development. We aimed: (1) to identify the optimal cut-off value of neck and low back discomfort among office workers and (2) to evaluate its predictive validity with future neck and low back pain, respectively.

Methods

At baseline healthy participants (n = 100) completed questionnaires, including the Borg CR-10 discomfort scale (on a 0–10 scale), and were followed for six months, during which musculoskeletal pain was assessed monthly. Logistic regression analyses were performed to assess the associations of baseline discomfort with the onset of future neck or low back pain. Sensitivity, specificity, and the area under the receiver operating characteristics curve were estimated to identify the optimal discomfort cut-off value predicting future pain.

Results

Borg CR-10 scores ≥ 3.5 for perceived neck and low back discomfort had acceptable sensitivity and specificity to predict future neck and low back pain, respectively. Perceived discomfort at baseline as a dichotomous measure (using the ≥ 3.5 cut-off) was a statistically significant predictor of future neck pain (OR = 10.33) and low back pain (OR = 11.81).

Conclusion

We identified the optimal cut-off value of the Borg CR-10 discomfort scale to identify office workers at increased risk of developing neck and low back pain. These findings might benefit ergonomists, primary health care providers, and occupational health researchers in developing targeted interventions.

Trunk sway changes in professional bus drivers during actual shifts on long-distance routes

Although professional bus drivers are required to perform their task while adopting a prolonged constrained sitting posture, existence of possible effects in terms of postural strategies has been scarcely investigated under actual working conditions. This study aimed to characterise modifications of trunk sway in 14 professional bus drivers during regular shifts performed on non-urban routes using a pressure-sensitive mat placed on the seat. Centre-of-pressure (COP) time series were extracted from body-seat pressure data to calculate sway parameters (i.e. sway area, COP path length, COP displacements and velocities). Results show generalised increase in trunk sway as driving progresses, which becomes statistically significant after approximately 70-100 minutes of continuous driving. This may indicate the adoption of specific strategies to cope with discomfort onset or a fatigue-induced alteration of postural features. Trunk sway monitoring of bus drivers may be useful in detecting postural behaviours potentially associated with deteriorating performance and discomfort onset. Practitioner summary: Professional bus drivers operate in sitting position for prolonged time. Such constrained posture may induce discomfort and fatigue. We investigated trunk sway during actual shifts using pressure-sensitive mats. Significant increase of sway was detected after 70 min of continuous driving. Body-seat pressure data could be used as discomfort and fatigue markers. Abbreviations: ANOVA-RM: analysis of variance with repeated measures; AP: antero-posterior; COP: center of pressure; EC: ellipse's centroid; ML: medio-lateral; SA: sway area; SP: sway path.

Back pain: An aftermath of Covid-19 pandemic? A Malta perspective

BACKGROUND

Back pain is the commonest musculoskeletal complaint across the world. The Covid-19 pandemic led to mitigating measures including remote working that enhanced a sedentary lifestyle. The aim of this study was to investigate whether back pain complaints have increased from pre-Covid-19 to during the Covid-19 period among the adult population of Malta, while exploring the possible contributing factors.

METHODS

An online survey was distributed through social media targeting the adult population of Malta. Questions on sociodemographic data, occurrence of back pain pre-Covid-19 and since the onset of Covid-19 was gathered, along with changes in behavioural attitudes, daily routine and physical activity. Descriptive and multiple logistic regression analyses were performed.

RESULTS

Out of the 388 responders, 30% experienced chronic back pain pre-Covid-19, 49% experienced back pain since Covid-19, with the majority of the latter claiming that they never experienced back pain before Covid-19. Significant changes were present in daily routine and physical activity (PA) patterns. Indeed, continuously sitting down (OR: 15.53; p ≤ 0.01), no PA (OR: 4.22; p ≤ <0.01), once a week PA (OR: 5.74; p ≤ <0.01), two to three times PA a week (OR: 2.58; p = 0.05) and four to five PA a week (OR: 3.46; p = 0.02) were associated with experiencing new onset back pain since the onset of Covid-19, when adjusted for sex, age, education and employment status.

CONCLUSION

The pandemic has changed population behaviour resulting in an enhanced back pain occurrence. This is anticipated to impact the individual's disability adjusted life years as well as increase the burden on the economy and healthcare services. A designated multidisciplinary action plan is recommended to reduce back pain impact.

Effects of Core Stabilization Exercise Programs on Changes in Erector Spinae Contractile Properties and Isokinetic Muscle Function of Adult Females with a Sedentary Lifestyle

This study aimed to investigate the effect of core stabilization exercises on the contractile properties and isokinetic muscle function of adult females with a sedentary lifestyle. We enrolled 105 adult females. Tensiomyography was performed on the erector spinae, and the isokinetic muscular functional test was performed on the trunk at an angular velocity of 60°/s and 90°/s. All participants performed the exercise for 60 min per day, 3 times a week, for 7 weeks. A Wilcoxon signed-rank test was performed at a significance level of 0.05. Tensiomyography (TMG) of the erector spinae revealed no significant post-exercise change in the contraction time; however, there was a significant post-exercise increase in the maximum radial displacement and mean velocity until 90% of the TMG was displaced. Additionally, the isokinetic muscular functional test of the trunk revealed a significant post-exercise increase in almost all variables. Our findings demonstrated that the core stabilization exercise reduced stiffness in the erector spinae, increased the velocity of erector spinae contraction, and effectively improved the isokinetic muscular function of the trunk.

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.

Sitting for Too Long, Moving Too Little: Regular Muscle Contractions Can Reduce Muscle Stiffness During Prolonged Periods of Chair-Sitting

In modern Western societies, sedentary behavior has become a growing health concern. There is increasing evidence that prolonged sitting periods can be associated with musculoskeletal disorders. While it is generally recognized that back muscle activity is low during chair-sitting, little is known about the consequences of minor to no muscle activity on muscle stiffness. Muscle stiffness may play an important role in musculoskeletal health. This study investigated the effects of regular muscle contractions on muscle stiffness in a controlled experiment in which participants sat for 4.5 h. Neuromuscular electrical stimulation in the lumbar region of the back was applied to trigger regular muscle contractions. Using stiffness measurements and continuous motion capturing, we found that prolonged sitting periods without regular muscle contractions significantly increased back muscle stiffness. Moreover, we were able to show that regular muscle contractions can prevent those effects. Our results highlight the importance of consistent muscle activity throughout the day and may help explain why prolonged periods of chair-sitting increase the susceptibility to common pathological conditions such as low back pain.

Effects on variation in shoulder, forearm and low back muscle activity from combining seated computer work with other productive office tasks: results from a simulation study

The effect on muscle activity variation of combining different office tasks is not known. We recorded electromyography from the upper trapezius (UT), wrist extensor (WE) and lumbar erector spinae (LES) in 24 office workers during five productive tasks, and breaks. Minute-to-minute variance was then estimated, by simulations, in a reference 'job' consisting of 85% sitting computer work and 15% breaks, and in 'jobs' where sitting computer work was replaced by different proportions of the other office tasks and breaks. Replacing sitting computer work with sitting non-computer work increased estimated variance by, in median, 23% (UT), 19% (WE) and 0% (LES). Replacing it with other tasks, in particular, standing computer and non-computer work, was less effective in increasing variance. Thus, some combinations of office tasks have a slight potential to increase muscle activity variation in the shoulder and lower arm, but not the lumbar back, while others will be ineffective. Practitioner summary: The need for exposure variation is often emphasised in office ergonomics. We estimated the effect on muscle activity in the shoulder, forearm and lumbar back of combining sitting computer work with other available tasks and breaks, finding that introduction of sitting non-computer tasks and non-desk work slightly increased variation; other tasks were essentially non-effective.

C. Mani K, Sadeghi Naeini H, Mohd Suadi Nata DH. Effectiveness of lumbar support with built-in massager system on spinal angle profiles among high-powered traffic police motorcycle riders: A randomised controlled trial

Traffic police riders are exposed to prolonged static postures causing significant angular deviation of the musculoskeletal, including the lumbar angle (L1-L5). This postural alteration contributes to awkward posture, musculoskeletal disorders and spinal injury, especially in the lower back area, as it is one of the most severe modern diseases nowadays. Thus, the study aimed to evaluate the effect of lumbar support with a built-in massager system on spinal angle profiles among traffic police riders. A randomised controlled trial (pre-testpost-test control design) was used to assess spinal angle pattern while riding the high-powered motorcycle for 20 minutes. Twenty-four traffic police riders were randomly selected to participate and 12 riders were assigned to the control group and 12 riders to the experimental group. The pre-test and post-test were conducted at a one-week interval. Each participant was required to wear a TruPosture Smart Shirt (to monitor spinal posture). The TruPosture Apps recorded the spinal angle pattern. The data indicated that the police riders using motorcycle seat with lumbar support and built-in massager system showed a huge improvement in maintaining posture which only involves slight spinal angle deviation changes from the spinal reference angle throughout the 20 minutes ride. The data collected then were analysed using the Mann-Whitney test and Wilcoxon signed-ranked test to verify a statistically significant difference between and within the control and experimental groups. There were significant differences in all sensors between the control group and experimental groups (p<0.05) and within the experimental group. According to the findings, it can be said that the ergonomic intervention prototype (lumbar support with built-in massager system) successfully helps to maintain and improve the natural curve of the spinal posture. This indirectly would reduce the risk of developing musculoskeletal disorders and spinal injury among traffic police riders.

Muscle activation of the upper trapezius and functional typing performance during computer typing task: A comparison of two different wrist immobilization methods

BACKGROUND

The aim of this study was to examine the effect of two different wrist immobilization methods on the muscle activation of the upper trapezius muscle and functional typing performance during computer typing tasks in office workers.

METHODS

The study was conducted on 11 healthy office workers. The study subjects were asked to type on a computer for 5 min (1) without splint or taping, (2) with a splint, (3) with rigid taping which limits the wrist flexion at the dominant side. The upper trapezius muscle activation was recorded by surface EMG during the task. The mean values obtained from EMG were normalized according to Maximum Voluntary Isometric Contraction (MVIC), comparisons were made according to %MVIC.

RESULTS

The office workers' mean age was 27.45 ± 3.64 years. There was no significant difference in immobilization methods between %MVIC on dominant (p = .508) and non-dominant (p = .213) sides. The upper trapezius of the non-dominant side showed higher electromyographic activity when the subjects used a splint (p = .013). There was a significant difference between splinting and rigid taping methods in typing performance (z = -2,491, p = .013).

CONCLUSION

There is no significant difference in the upper trapezius muscle activation between the splint and rigid taping methods during the computer typing task on the dominant side. The typing performance was affected more during splint use compared to rigid tape application. Considering the importance of work efficiency in employees, rigid taping might be considered as an alternative splinting for wrist immobilization in office workers.

Effects of the Multidimensional Treatment on Pain, Disability, and Sitting Posture in Patients with Low Back Pain: A Randomized Controlled Trial

The purpose of this study was to investigate the effects of multidimensional approach model on the pain, disability, and sitting posture in patients with nonspecific low back pain (LBP). Sixty LBP patients were recruited and were randomly divided into two groups: multidimensional treatment (MT) group (n = 30) and unimodal treatment (UT) group (n = 30). All participants underwent 48 sessions of treatment (40 min/session, two sessions per day, 2 days per week) for 12 weeks. The MT group conducted a core stability exercise twice a day and additionally provided training on pain principles and management methods. The UT group only performed a core stability exercise twice a day. The visual analog scale (VAS) and Oswestry Disability index (ODI) were used to measure pain intensity and disability. Thoracolumbar kyphosis and lumbar lordosis in the sitting position were measured using a motion capture system. After training, the pain and disability in the MT group improved significantly greater than the UT group (p < 0.05). In the MT group, the pain relief effect persisted 3 months after the end of training. Thoracolumbar kyphosis and lumbar lordosis in the MT group were significantly improved compared to the UT group (p < 0.05). Thus, MT combined with core stability exercise may be used to improve the pain, disability, and sitting posture in patients with LBP.

Trunk muscle endurance, strength and flexibility in rural subsistence farmers and urban industrialized adults in western Kenya

OBJECTIVES

High trunk muscle endurance, strength, and moderate flexibility reportedly help maintain musculoskeletal health, but there is evidence for tradeoffs among these variables as well as sex differences in trunk muscle endurance and strength. To test if these observations extend similarly to both men and women in nonindustrial and industrial environments, we investigated intra-individual associations and group and sex differences in trunk muscle endurance, strength, and flexibility among 74 (35 F, 39 M; age range: 18-61 years) adults from the same Kalenjin-speaking population in western Kenya. We specifically compared men and women from an urban community with professions that do not involve manual labor with rural subsistence farmers, including women who frequently carry heavy loads.

METHODS

Trunk muscle endurance, strength, and flexibility were measured with exercise tests and electromyography (EMG).

RESULTS

We found a positive correlation between trunk extensor strength and endurance (R = .271, p ≤ .05) and no associations between strength or endurance and flexibility. Rural women had higher trunk extensor and flexor endurance, EMG-determined longissimus lumborum endurance, and trunk extensor strength than urban women (all p ≤ .05). Rural women had higher trunk extensor and flexor endurance than rural men (both p ≤ .05). Urban women had lower trunk flexor and extensor endurance than urban men (both p ≤ .01).

CONCLUSIONS

High levels of physical activity among nonindustrial subsistence farmers, particularly head carrying among women, appear to be associated with high trunk muscle endurance and strength, which may have important benefits for helping maintain musculoskeletal health.

Effects of Prolonged Sitting with Slumped Posture on Trunk Muscular Fatigue in Adolescents with and without Chronic Lower Back Pain

Background and Objectives: This study investigated the effects of prolonged sitting on trunk muscular fatigue and discomfort in participants with and without chronic lower back pain (LBP). Material and Methods: This study included 15 patients with LBP and 15 healthy controls. All participants were instructed to sit on a height-adjustable chair with their knee and hip joints bent at 90° for 30 min, in slumped sitting postures. Surface electromyography was used to assess the median frequency of the internal obliques (IO)/transversus abdominis (TrA) and multifidus (MF) muscles. Perceived discomfort was measured using a Borg category ratio-scale. Median frequency of the trunk muscles and perceived discomfort after 30 min of sitting were compared with baseline. Result: There were no significant differences within the group and between both groups in the median frequency of bilateral IO and MF muscles. The LBP group showed significantly greater perceived discomfort after prolonged sitting, as compared to the control group. Conclusions: Prolonged sitting with slumped posture could increase the risk of experiencing lower back discomfort.

Is active sitting on a dynamic office chair controlled by the trunk muscles?

Today’s office chairs are not known to promote active sitting or to activate the lumbar trunk muscles, both of which functions are ergonomically recommended. This study investigated a newly developed dynamic office chair with a moveable seat, specifically designed to promote trunk muscle controlled active sitting. The study aimed to determine the means by which the seat movement was controlled during active sitting. This was accomplished by quantifying trunk and thigh muscular activity and body kinematics. Additionally, the effect of increased spinal motion on muscular activity and body kinematics was analysed. Ten subjects were equipped with reflective body markers and surface electromyography on three lumbar back muscles (multifidus, iliocostalis, longissimus) and two thigh muscles (vastus lateralis and medialis). Subjects performed a reading task during static and active sitting in spontaneous and maximum ranges of motion in a simulated office laboratory setting. The temporal muscle activation pattern, average muscle activity and body segment kinematics were analysed and compared using Friedman and post-hoc Wilcoxon tests (p≤0.05). Active sitting on the new chair significantly affected the lumbar trunk muscles, with characteristic cyclic unloading/loading in response to the seat movement. Neither thigh muscle activity nor lateral body weight shift were substantially affected by active sitting. When participants increased their range of motion, the lumbar back muscles were activated for longer and relaxation times were shorter. The characteristic activity pattern of the lumbar trunk muscles was shown to be the most likely dominant factor in controlling seat movement during active sitting. Consequently, the new chair may have a potential positive impact on back health during prolonged sitting. Further studies are necessary to analyse the frequency and intensity of active sitting during daily office work.

Impact of COVID-19Quarantine on Low Back Pain Intensity, Prevalence, and Associated Risk Factors among Adult Citizens Residing in Riyadh (Saudi Arabia): A Cross-Sectional Study

This study aimed to estimate the effect of the coronavirus disease 2019 (COVID-19) quarantine on low back pain (LBP) intensity, prevalence, and associated risk factors among adults in Riyadh (Saudi Arabia). A total of 463 adults (259 males and 204 females) aged between 18 and 64 years and residing in Riyadh (Saudi Arabia) participated in this cross-sectional study. A self-administered structured questionnaire composed of 20 questions regarding demographic characteristics, work- and academic-related aspects, physical activity (PA), daily habits and tasks, and pain-related aspects was used. The LBP point prevalence before the quarantine was 38.8%, and 43.8% after the quarantine. The LBP intensity significantly increased during the quarantine. The low back was also the most common musculoskeletal pain area. Furthermore, during the quarantine, a significantly higher LBP intensity was reported by those individuals who (a) were aged between 35 and 49 years old, (b) had a body mass index equal to or exceeding 30, (c) underwent higher levels of stress, (d) did not comply with the ergonomic recommendations, (e) were sitting for long periods, (f) did not practice enough physical activity (PA), and (g) underwent teleworking or distance learning. No significant differences were found between genders. The COVID-19 quarantine resulted in a significant increase in LBP intensity, point prevalence, and most associated risk factors.

Characterization of Home Working Population during COVID-19 Emergency: A Cross-Sectional Analysis

Evidence about the characterization of home workers in terms of both work-related outcomes and health issues is lacking. The purpose of this cross-sectional study was to examine the impact of home working on perceived job productivity and satisfaction, work-related stress, and musculoskeletal (MSK) issues. We included 51 mobile workers, collecting data about demographic characteristics, working experience, job productivity, and stress. Job satisfaction was assessed through the Utrecht Work Engagement Scale (UWES), while MSK pain was investigated by the Brief Pain Inventory (BPI) and Fear Avoidance Beliefs Questionnaire (FABQ). Moreover, a home workplace analysis had to be carried out according to current Italian regulations. Participants declared that they were less productive (39.2%) but less stressed (39.2%) and equally satisfied (51%) compared to the time of office working. Regarding MSK disorders, low back pain (LBP) was referred by 41.2% of home workers and neck pain by 23.5% of them. Neck pain worsened in 50% of home workers, while LBP did not exacerbate in 47.6% of cases. Home workers with MSK pain reported a lower job satisfaction. Depending on our data, the home environment seems to be not adequate in the mobile worker population, with an increased risk for mental health and MSK problems, particularly affecting the spine. Addressing these issues can significantly reduce risks for health, thus, improving job productivity and satisfaction and reducing cost.

Do different sit-stand workstations influence lumbar kinematics, lumbar muscle activity and musculoskeletal pain in office workers? A secondary analysis of a randomized controlled trial

Purpose. This study investigated the effect of different sit-stand workstations on lumbar spine kinematics, lumbar muscle activity and musculoskeletal pain. Methods. Thirty-two office workers were randomized to one of three sit-stand workstations (Group 1, ratio of minutes spent sitting to standing each hour at work 40:20, n = 8; Group 2, 30:30, n = 6; Group 3, 20:40, n = 7) and a control group (usual sitting, n = 11). Intervention groups (Groups 1, 2 and 3) were collapsed into one group for analysis (n = 21). Data on lumbar kinematics and muscle activity were only collected for 25 participants due to equipment availability. Results. Participants in the intervention group had lower overall lumbar spine flexion angles during the workday compared to the control group (mean difference 10.6°; 95% confidence interval [-18.1, -3.2]; p = 0.008; Cohen's d = 1.5). There were no between-group differences for the remaining kinematic measures (i.e., mean flexion angle in standing and sitting, mean side flexion angle in standing and sitting, and percentage of time in upright sitting), muscle activity or presence of musculoskeletal pain. Conclusions. Sit-stand workstations reduced overall lumbar spine flexion angles over the course of a workday but had no effect on other kinematic measures, lumbar spine muscle activity or musculoskeletal pain.Trial registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12615001018505..

Prevalence of Incorrect Posture among Children and Adolescents: Finding from a Large Population-Based Study in China

Evidence showed that bad posture in adulthood is often formed from the childhood, and individuals with severe incorrect posture may be associated with the progress of scoliosis. We aimed to estimate the prevalence of incorrect posture in Chinese children and adolescents and to describe the epidemiological findings stratified by the demographic characteristics. A total of 595,057 students were screened; the overall prevalence of incorrect posture in children and adolescents was 65.3%, and around 3.7% of the students were referred to radiography. Girls had a higher prevalence of incorrect posture than boys, students aged >10 years accounted for a higher rate of incorrect posture than students aged <10 years. We found that Chinese children and adolescents had a high prevalence of incorrect posture, with girls and older students being an especially high-risk group. Early interventions targeted for students with incorrect posture are urgently needed.

Evaluating the validity of diagnostic methods for scoliotic posture of primary school children

Primary school children are exposed to asymmetric loads that lead to an imbalance of postural muscles and a violation of the body relative symmetry. Mass screening examinations in schools for scoliotic posture and scoliosis are conducted primarily through the Adams test. It has low reproducibility and a high frequency of false negative results. In practice, various methods for diagnosing posture disorders are also used. Some methods are based on the evaluation of postural muscles static endurance, elasticity and proportionality of their functional capabilities. Others are based on a comprehensive assessment of the ability to maintain an upright posture rationally. The third ones are based on the analysis of the tonic vibration and H-reflex of skeletal muscles on both sides of the vertebral column. All the above mentioned methods definitely have diagnostic potential. Therefore it was decided to determine the validity of some common methods for diagnosing posture disorders based on the analysis of their mutual congruence. Based on the results of the experiment, a reliable correlation between the studied parameters was established. It in turn allows us to judge the congruence of the considered diagnostic methods and, accordingly, the high probability of their validity.

The musculoskeletal and cognitive effects of under-desk cycling compared to sitting for office workers

Alternate work positions are being considered as a way to address sedentary behaviour for office workers. This study evaluated the effect of two hours of just-sitting versus sitting while under-desk cycling on musculoskeletal discomfort and cognitive function (sustained attention and creative problem solving). To consider mechanisms, muscle fatigue, kinematics and mental state were also measured. Discomfort increased significantly across all body areas with knee and ankle discomfort greater (in a clinically meaningful manner) in under-desk cycling. Sustained attention reaction time was the only cognitive measure to show a difference between conditions (slower for under-desk cycling [β-34.82 CI (-62.12 to -7.53)]). There was no evidence of muscle fatigue, while kinematic differences between conditions were identified. Mental state deteriorated over time in both conditions. This study found no clear benefit of under-desk cycling compared to just-sitting for musculoskeletal health and cognitive function measures.

Experimental platform to facilitate novel back brace development for the improvement of spine stability

The spine or 'back' has many functions including supporting our body frame whilst facilitating movement, protecting the spinal cord and nerves and acting as a shock absorber. In certain instances, individuals may develop conditions that not only cause back pain but also may require additional support for the spine. Common movements such as twisting, standing and bending motions could exacerbate these conditions and intensify this pain. Back braces can be used in certain instances to constrain such motion as part of an individual's therapy and have existed as both medical and retail products for a number of decades. Arguably, back brace designs have lacked the innovation expected in this time. Existing designs are often found to be heavy, overly rigid, indiscrete and largely uncomfortable. In order to facilitate the development of new designs of back braces capable of being optimised to constrain particular motions for specific therapies, a numerical and experimental design strategy has been devised, tested and proven for the first time. The strategy makes use of an experimental test rig in conjunction with finite element analysis simulations to investigate and quantify the effects of back braces on flexion, extension, lateral bending and torsional motions as experienced by the human trunk. This paper describes this strategy and demonstrates its effectiveness through the proposal and comparison of two novel back brace designs.

Myoelectric Activity of Individual Lumbar Erector Spinae Muscles Variation by Differing Seat Pan Depth

Background:

The chair influences the position of the user in relation to his or her devices. Prolonged static sitting is a frequently mentioned risk factor for low back pain. Seat design, thus, plays an important role in the study of human sitting. Quantitative information is needed on what happens to body when one sits in chairs with different seat depth.

Objective:

To determine the myoelectric activity (EMG) of individual lumbar erector spinae muscles after sitting in chairs with different seat pan depth.

Methods:

EMG recordings were taken using surface electrodes placed on the lumbar erector spine muscles of 25 normal, volunteer subjects. EMG recordings for muscle activity were made while the study participants were in a comfortable position and performed the required tasks. The experiments investigated with 3 seat depths according to the 5^th, 50^th and 95^th percentiles of the buttock popliteal length. The recorded EMG data were normalized to the maximal voluntary contraction. The mean EMG recording was calculated for each of the 3 chairs tested. A mixed model was used to assess the differences among the situations.

Results:

A significant (p<0.05) difference was observed between the mean EMG recordings for the 3 tested seat pan depths. EMG activity was higher in seats with the 5^th and 95^th percentiles compared with that for the seat with 50^th percentile of buttock popliteal length depth.

Conclusion:

The seat pan depth used during a comfortable position has a significant effect on the level of myoelectric activity in the lumbar erector spinal muscles. The finding of this study may contribute to our understanding of the biomechanics of sitting.

Sitting less at work: a qualitative study of barriers and enablers in organisations of different size and sector

BACKGROUND

Prolonged sitting is associated with a range of chronic health conditions and working in office-based jobs is an important contributor to total daily sitting time. Consequently, interventions to reduce workplace sitting have been developed and tested; however, no single intervention strategy consistently produces reductions in workplace sitting time. Exploring barriers and enablers to sitting less at work has been shown to support the development of more effective interventions. In order to address these barriers and enablers during the development and implementation of sit less at work interventions, it is important to understand how they may differ in different types of organisation, an area which has not yet been explored. The main aim of this study was to determine whether barriers and enablers to sitting less at work varied between organisations of different size and sector.

METHODS

A qualitative study design was used. Four organisations of different sizes and sectors participated: a small business, a charity, a local authority and a large corporation. A total of ten focus groups comprising 40 volunteer employees were conducted. Focus groups were audio-recorded and transcribed verbatim. Transcripts were then thematically analysed using pre-defined themes, but analysis also allowed for emergence of additional themes.

RESULTS

Barriers and enablers which were consistently raised by participants across all four organisations primarily included: individual-level factors such as habits and routines, and personal motivations and preferences; and factors relating to the internal physical environment. Barriers and enablers that differed by organisation mainly related to: organisational-level factors such as organisational culture, organisation size, and ways of working; and factors relating to the broader social, economic and political context such as the idea of presenteeism, and the impact of wider economic and political issues.

CONCLUSIONS

This study found that although some themes were consistently raised by participants from organisations of different size and sector, participants from these organisations also experienced some different barriers and enablers to sitting less at work. For future research or practice, the study findings highlight that organisation-specific barriers and enablers need to be identified and addressed during the development and implementation of sit less at work interventions.

Variation in upper extremity, neck and trunk postures when performing computer work at a sit-stand station

Sit-stand tables are introduced in offices to increase variation in gross body posture, but the extent to which upper body posture variation is also affected has not previously been addressed. Neck, trunk, and upper arm postures (means and minute-to-minute variances) were determined during periods of sitting and standing from 24 office workers using sit-stand tables to perform computer work. Posture variability resulting from different temporal compositions of sitting and standing computer work was then predicted for the neck, trunk and upper arm by simulations. Postural variability during computer work could be increased up to three-fold when 20-60% of the work was performed standing (i.e. 40-80% performed sitting), compared to performing computer work only sitting. The exact composition of sit-stand proportions leading to maximum variability, as well as the potential size of the increase in variability, differed considerably between workers. Guidelines for sit-stand table use should note these large inter-individual differences.

Acute effect of full time office work in real environment on postural actions and lumbar range of motion

INTRODUCTION

Prolonged sitting is often proposed as a risk factor for low back pain development. The purpose of this study was to evaluate the acute effect of full time office work on sensorimotor trunk functions.

METHODS

Seventeen healthy office workers participated in the study. Maximal lumbar flexion range of motion, anticipatory postural adjustments and postural reflex reactions were tested before and after full time office work in a real life environment.

RESULTS

There were longer onset latencies of postural reflexive reactions and decreased response amplitudes of anticipatory postural adjustments after full time office work, but these were significant only for the obliquus externus abdominis muscle. No changes in lumbar range of motion was found.

CONCLUSION

To our knowledge this is the first study that evaluates the effect of full time office work on postural actions and lumbar RoM. We found an absence of normal human circadian flexibility in the lumbar spine and some changes in postural actions. We propose that active trunk stiffness increase to compensate for decreased passive stiffness after prolonged seated work. Further studies are needed to confirm this assumption.

The Short Term Musculoskeletal and Cognitive Effects of Prolonged Sitting During Office Computer Work

Office workers are exposed to high levels of sedentary time. In addition to cardio-vascular and metabolic health risks, this sedentary time may have musculoskeletal and/or cognitive impacts on office workers. Participants (n = 20) undertook two hours of laboratory-based sitting computer work to investigate changes in discomfort and cognitive function (sustained attention and problem solving), along with muscle fatigue, movement and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.43 [1.33–1.53]) reaching clinically meaningful levels in the low back and hip/thigh/buttock areas. Creative problem solving errors increased (β = 0.25 [0.03–1.47]) while sustained attention did not change. There was no change in erector spinae, trapezius, rectus femoris, biceps femoris and external oblique median frequency or amplitude; low back angle changed towards less lordosis, pelvis movement increased, and mental state deteriorated. There were no substantial correlations between discomfort and cognitive function. The observed changes suggest prolonged sitting may have consequences for musculoskeletal discomfort and cognitive function and breaks to interrupt prolonged sitting are recommended.

The development, implementation and evaluation of interventions to reduce workplace sitting: a qualitative systematic review and evidence-based operational framework

BACKGROUND

Prolonged sitting is associated with increased risks of cardiovascular disease, Type 2 diabetes, some cancers, musculoskeletal disorders and premature mortality. Workplaces contribute to a large proportion of daily sitting time, particularly among office-based workers. Interventions to reduce workplace sitting therefore represent important public health initiatives. Previous systematic reviews suggest such interventions can be effective but have reported wide variations. Further, there is uncertainty as to whether effectiveness in controlled trials can be replicated when implemented outside the research setting. The aims of this review are to identify factors important for the implementation of workplace sitting interventions and to translate these findings into a useful operational framework to support the future implementation of such interventions.

METHODS

A qualitative systematic review was conducted. Four health and social science databases were searched for studies set in the workplace, with office-based employees and with the primary aim of reducing workplace sitting. Extracted data were primarily from author descriptions of interventions and their implementation. Inductive thematic analysis and synthesis was undertaken.

RESULTS

Forty studies met the inclusion criteria. Nine descriptive themes were identified from which emerged three higher-order analytical themes, which related to the development, implementation and evaluation of workplace sitting interventions. Key findings included: the importance of grounding interventions in theory; utilising participative approaches during intervention development and implementation; and conducting comprehensive process and outcome evaluations. There was a general under-reporting of information relating to the context within which workplace sitting interventions were implemented, such as details of local organisation processes and structures, as well as the wider political and economic landscape, which if present would aid the translation of knowledge into "real-world" settings.

CONCLUSIONS

These findings provided the basis for an operational framework, which is a representation of all nine descriptive themes and three higher-order analytical themes, to support workplace sitting intervention development, implementation and evaluation. Once tested and refined, this framework has the potential to be incorporated into a practical toolkit, which could be used by a range of organisations to develop, implement and evaluate their own interventions to reduce workplace sitting time amongst staff.

Morphology of the lumbar multifidus muscle in lumbar disc herniation at different durations and at different ages

The aim of the present study was to evaluate the relative functional volume of bilateral lumbar multifidus (LM) muscles across different stages and ages of patients with lumbar disc herniation (LDH). The relative functional volumes of LM muscles in both non-affected and affected sides in the L4-L5 and L5-S1 segmental level were measured in a resting prone position, and visual analogue score (VAS) for pain and Japanese Orthopedic Association (JOA) scores were recorded. The correlation between changes in the relative net volume of LM muscles and times of onset, ages, VAS and JOA scores were analyzed. A total of 327 cases were selected. The affected sides of LM muscles could present a certain degree of atrophy in stages >3 weeks. During the duration of the course, all cases presented different degrees of LM muscle atrophy. In addition, the degree of LM muscle atrophy was positively correlated with its duration. Age could influence the degree of LM muscle atrophy. Patients with unilateral LDH had <10% asymmetry on relative functional volume in the youth group. At the L4-L5 segments, patients with unilateral LDH had >10% asymmetry within the course of 3 months in the elderly group. The reduced rate of the relative functional net LM muscle volume was positively correlated with VAS scores, age, duration and JOA scores. In conclusion, the reduced rate of relative functional net LM muscle volume was positively correlated with age, duration, VAS scores and JOA scores. Although these findings are unreliable markers of lumbar pathology in an individual level for use in clinical or research settings, there is a notable importance of early intervention in LM muscle atrophy.

Total sitting time, leisure time physical activity and risk of hospitalization due to low back pain: The Danish Health Examination Survey cohort 2007–2008

Aims: This study aimed to test the hypotheses that a high total sitting time and vigorous physical activity in leisure time increase the risk of low back pain and herniated lumbar disc disease. Methods: A total of 76,438 adults answered questions regarding their total sitting time and physical activity during leisure time in the Danish Health Examination Survey 2007–2008. Information on low back pain diagnoses up to 10 September 2015 was obtained from The National Patient Register. The mean follow-up time was 7.4 years. Data were analysed using Cox regression analysis with adjustment for potential confounders. Multiple imputations were performed for missing values. Results: During the follow-up period, 1796 individuals were diagnosed with low back pain, of whom 479 were diagnosed with herniated lumbar disc disease. Total sitting time was not associated with low back pain or herniated lumbar disc disease. However, moderate or vigorous physical activity, as compared to light physical activity, was associated with increased risk of low back pain (HR = 1.16, 95% CI: 1.03–1.30 and HR = 1.45, 95% CI: 1.15–1.83). Moderate, but not vigorous physical activity was associated with increased risk of herniated lumbar disc disease. Conclusions: The results suggest that total sitting time is not associated with low back pain, but moderate and vigorous physical activity is associated with increased risk of low back pain compared with light physical activity.

Repeated end range spinal movement while seated abolishes the proprioceptive deficit induced by prolonged flexed sitting posture. A study assessing the statistical and clinical significance of spinal position sense

BACKGROUND

Sustained spinal flexion has been proposed to affect the properties of spinal tissues, increase postural muscle's activation latency and act detrimentally on proprioception.

OBJECTIVES

This study evaluated the effect of flexed posture (FP) on spinal proprioception and assessed the immediate effect of spinal movement on the presumable flexion-induced proprioceptive deficit.

DESIGN

Clinical measurement study.

METHODS

Marker-based kinematic analyses of the head, spine, and pelvis were conducted on 50 individuals. Subjects were educated in a lordotic sitting posture (IOSP) that they reproduced immediately; after 10 and 30 min in FP; and after sagittal spinal movement. Nine sagittal angles were calculated. Absolute error (AE) and constant error (CE) were used to evaluate repositioning accuracy. Repeated measures ANOVA was used to test for significant differences in angles obtained among postures, as well as for the AE and CE calculated from the trials.

RESULTS

No significant differences were found in reposition error (RE) after immediate reproduction of IOSP (all p > 0.0083). Following FP AEs presented significant differences for head (4.1°), head protraction (1.9°), head tilt (2.1°), lumbar (3.2°) and pelvis angle (2.1°). CEs revealed significant differences for head protraction (-1.8°) and lumbar angle (-3.5°). No significant differences were found for AE and CE after spinal sagittal movement (all p > 0.0083).

CONCLUSIONS

Prolonged FP can affect spinal position sense, but sagittal spinal movement can abolish the proprioceptive deficit. The significant differences documented, may be of limited clinical utility given their magnitude, and the reliability data presented may be of use in reinterpreting previously documented proprioceptive analyses.