A novel approach for evaluating level, frequency and duration of lumbar posture simultaneously during work.

Changes in stair ascent biomechanics two to eight years after ACL reconstruction are associated with patient-reported outcomes

Variability of exposure can be a source of information bias in studies with exposure assessment based on the use of a sample of workers in each occupational group under study. This paper presents a method to assess the rate of exposure misclassification from the magnitude of overlap of exposure distributions and, consequently, to evaluate the bias to risk estimates in cross-sectional and prospective studies. The percentage of work-time with trunk flexion and rotation was studied in five occupational groups. The rate of misclassification of exposure to trunk flexion and rotation varied from 0.03 to 0.35. Misclassification below 0.10 was found only for occupational groups with at least a 14-fold difference in mean exposure. Higher rates of misclassification can easily bias the risk estimates up to 50%. In the cross-sectional design the odds ratio was more sensitive to bias than the prevalence rate ratio. The estimate of the relative risk in a prospective study design was the least biased.

The aims of this study were to describe job-specific factors and prevalence of musculoskeletal pains (MSPs) by the occupation and body regions in the past 12 months and past month, to analyse multisite and disabling pain and sick leave among office workers (OW), nurses and caregivers (CG); and to find relationships between the observed indicators. The study groups were selected by random sample method. Questionnaire responses on demographic parameters, job-specific factors, and MSPs by body parts in the past 12 months (MSP-12) and past month (MSP-1) were analysed. A questionnaire was sent to 1291 participants. The response rate was 54%. Most of the participants were women, with mean age 41.2 (±11.5) years, working on average 42.8 (±6.7) hours per week and had service length more than five years. Repetitive movements of wrist/hands and working under time pressure were more often reported risk factors by the nurses. Lifting weights 25 kg and more, climbing up and down, kneeling more than one hour a day and piecework finished in the work shift were the most often reported job-related risk factors for the CGs. Use of a keyboard was the same frequent work-related risk factor for the OWs. The most prevalent MSP-12 was low back pain for CGs (66.3%) and nurses (56.1%) and neck pain for OWs (51.5%). The most often reported MSP-1 was shoulder pain for nurses and OWs (84.4% and 65.7%, correspondingly), and elbow pain for CGs (74.9%). In the the entire sampled group, low back pain (53.9%) in the past 12 months and shoulder pain (70.9%) in the past month were the most often reported pain regions. A higher prevalence of multiple and disabling MSP and sickness absence were reported by CGs, compared to other occupation groups (p < 0.05). Correlation analysis showed positive relationships between job-related risk factors, like repetitive movements, physical load, and time demands, and MSPs and sick leave, especially among CGs (p < 0.05). Job-specific factors need more attention to prevent multiple and disabling pain and sick leave among office and hospital workers.

The effects of changes in the anterior-posterior center of pressure (AP-COP) position on the lower limb joint moments during double-leg squatting remain unclear. The purpose of this study was to determine the effects of AP-COP positional changes on the hip, knee, and ankle extensor moments during double-leg squatting. Sixteen male participants (22.1 ± 1.5 years) performed double-leg squatting under two conditions (anterior and posterior COP conditions) with visual feedback on their COP positions. Kinematics and kinetics were analyzed using a three-dimensional motion analysis system and force plates. The hip, knee and ankle flexion angles and extensor moments at peak vertical ground reaction force were compared between the two conditions using paired t tests. The COP position was 53.5 ± 2.4% of the foot length, starting from the heel, under the anterior condition and 44.4 ± 2.1% under the posterior condition (P < 0.001). The knee extensor moment was significantly smaller under the anterior than the posterior COP condition (P = 0.003, 95% confidence interval (CI) -0.087 to -0.021 Nm/kg/m), while the ankle extensor moment significantly larger under the anterior COP condition than under the posterior COP condition (P < 0.001, 95% CI 0.113 to 0.147 Nm/kg/m). There was no significant difference in hip extensor moment (P = 0.431). The ankle dorsiflexion angle was significantly larger under the anterior than the posterior COP condition (P = 0.003, 95% CI 0.6 to 2.6°), while there was no difference in trunk, hip, or knee flexion angle. The present results indicate that changes in the AP-COP position mainly affect the ankle and knee extensor moments during double-leg squatting, while the effect on the lower limb joint and trunk flexion angles was limited. Visual feedback on the AP-COP position could be useful for modifying the ankle and knee extensor moments during double-leg squatting.

The effect of trunk flexion angle on lower limb mechanics during running.

Introduction: Work-related musculoskeletal disorders are the most common and costly preventable occupational problem that office workers suffer from the discomfort associated with these disorders. The aims of this study were to a) investigate the prevalence of low back pain (LBP) and b) continuously assess the trunk postures of office workers&#x0D; .Materials and Methods: Thirty-six office workers of a medical university participated in this cross-sectional study. Thirty-six office workers of a medical university participated in this cross-sectional study. The prevalence of LBP was determined using the Nordic Musculoskeletal Questionnaire. Work trunk postures were measured using an inclinometer.&#x0D; Results: More than half of the subjects reported LBP. There was a significant relationship between LBP with age, work experience, working hours, and gender (p &lt;0.05). The mean maximum trunk flexion angle was 35.41±13.72, and the mean maximum angle of lateral bend in the frontal plane was 9.86±3.2. The mean trunk angles for all percentiles and plates studied were significantly different between men and women; It was more in women than men (p &lt;0.05).&#x0D; Conclusion: The results of this study showed that there are awkward and static postures lumbar among office workers that can be considered risk factors for developing LBP. The findings can help to establish guidelines regarding prioritizing ergonomic interventions to reduce the prevalence of LBP among office workers.

This study investigated changes in craniocervical and trunk flexion angles and gluteal pressure on both sides during visual display terminal (VDT) work with continuous cross-legged sitting. The gluteal pressures of ten VDT workers, who were recruited from laboratories, were measured using a Teckscan system and videotaped using a single video camera to capture the craniocervical and trunk flexion angles during VDT work at 30 s, 10, 20 and 30 min. The craniocervical angle was significantly increased at 10 and 20 min compared with the initial angle (p<0.05). The trunk flexion angle was significantly decreased at 30 s, 10, 20 and 30 min (p<0.05). The gluteal pressure of the crossed-leg side significantly increased at 30 s, 10 and 20 min (p<0.05). The gluteal pressure of the uncrossed-leg side significantly decreased at 30 s (p<0.05). We found that cross-legged sitting during VDT work may exert disadvantageous postural effects resulting from craniocervical and trunk flexion angles and gluteal pressure. Therefore, this posture could not be recommended during long-term VDT work.

Effects of handrail use during sit-to-stand in the third trimester

This study used personal air samplers to assess the concentration of airborne microplastics exposed by different occupational groups during their working hours. The personal air sampler was placed in the “breathing zone” of the worker during working hours to collect microplastic exposure data. Occupations examined included housekeepers, laundromat staff, office workers, van drivers, street vendors, maintenance technicians in wastewater treatment plants, and waste segregation officers in the university and market. The level of airborne microplastic exposure was found to be influenced by the daily activities and environmental conditions of the workplace. Waste segregation officers in the university and market exhibited the highest levels of exposure to airborne microplastics, at 3964 ± 2575 microplastics per cubic meter (n/m3) and 3474 ± 678 n/m3, respectively. Further analysis focused on airborne microplastics less than 10 µm in size which can be taken in through inhalation. During the 8 h working period, the waste segregation officer in the university recorded the highest 10 µm airborne microplastic intake, at 5460 pieces, followed by the waste segregation officer in the market at 3301 pieces, housekeepers at 899 pieces, van drivers at 721 pieces, maintenance technicians in WWTPs at 668 pieces, laundromat staff at 454 pieces, street vendors at 249 pieces, and office workers at 131 pieces.

Towards exposure limits for working postures and musculoskeletal symptoms – a prospective cohort study

BackgroundFemale smoking rate in South Korea did not decrease in recent 5 years and had been underreported while males smoking rate had decreasing trends. Some reports demonstrated that young women...

Associations between work-related musculoskeletal disorders (WMSDs) and awkward postures and repetitive movements have been established. Action levels for elevated arms, trunk flexion, and fast movements have been suggested. With today's prolonged working life, older workers in manual jobs may be at increased risk for WMSDs. The aim of this study was therefore to assess postural workload in older workers in four physically demanding occupational groups using technical measurements and compare the exposure of the groups with each other's and with the action level. Postures and movements were measured for the right upper arm and the trunk using inertial measurement units (IMUs) during 3 workdays in construction workers (n = 35), kitchen workers (n = 37), cleaners (n = 27), and assistant nurses (n = 25), all over 50 years. Angle and angular velocity were computed, and time exceeding suggested angular cut-offs was assessed. Group mean and variance components within and between subjects were estimated in one-way random effect models. One-way ANOVA tests were conducted to compare exposure variables between the occupational groups. Construction workers spent more time with arms >60° than other occupational groups (7.9% vs. 4.4-5.6%) and >90° (2.8% vs. 1.0-1.3%). Across groups, a substantial share of days exceeded suggested action level for arm elevation >30° (8.0-24.6%) and >60° (6.3-22.7%). Cleaners had the highest 50th percentile trunk flexion (15.3°), while construction workers spent the most time with trunk flexion >45° (12.6%) and >60° (7.4%); exceedances of recommended levels occurred in up to 39% of days. Kitchen workers and cleaners exhibited more time with fast arm movements (31.8-35.6% vs. 23.9-24.0%). Considerable variability was observed both within and between individuals. In the included occupational groups, in workers over 50 years, arm elevation and trunk flexion may often exceed recommended levels. Since the physical capacity is decreasing with age, this indicates elevated musculoskeletal risks, and there is a clear need for targeted ergonomic measures to support sustainable working lives.

Task-Specific Perturbation Training Improves the Recovery Stepping Responses by Women With Knee Osteoarthritis Following Laboratory-Induced Trips.

Trunk exoskeletons are an emerging technology that could reduce spinal loading, guide trunk motion, and augment lifting ability. However, while they have achieved promising results in brief laboratory studies, they have not yet been tested in longer-term real-world studies - partially due to reliance on stationary sensors such as cameras. To enable future real-world evaluations of trunk exoskeletons, this paper describes two preliminary studies on using inertial measurement units (IMUs) to collect kinematic data from an exoskeleton wearer. In the first study, a participant performed three activities (walking, sit-to-stand, box lifting) while trunk flexion angle was measured with both IMUs and reference cameras. The mean absolute difference in flexion angle between the two methods was 1.4° during walking, 3.6° during sit-to-stand and 5.2° during box lifting, showing that IMUs can measure trunk flexion with a reasonable accuracy. In the second study, six participants performed five activities (standing, sitting straight, slouching, 'good' lifting, 'bad' lifting), and a naïve Bayes classifier was used to automatically classify the activity from IMU data. The classification accuracy was 92.2%, indicating the feasibility of automated activity classification using IMUs. The IMUs will next be used to obtain longer-term recordings of different activities performed both with and without a trunk exoskeleton to determine how the exoskeleton affects a person's posture and behavior.

Injury prevention training using a global systems approach was designed to develop integrated trunk-lower extremity neuromuscular control using whole-body, rotational forces about the vertical Z-axis during simulated sports movements. Compared with traditional hip-focused exercises, injury prevention training using a global systems approach could improve kinetic and kinematic measures related to anterior cruciate ligament injury. Controlled laboratory study. Level 3. A total of 39 male and female athletes received 6 weeks of either global systems approach (n = 20), or hip-focused strengthening, balance, and plyometrics training (n = 19) exercises. Before and after the training program, participants performed a single-leg vertical drop jump task on their dominant leg. Peak vertical ground-reaction forces (GRFs), peak knee abduction, internal rotation moments, peak hip flexion, hip adduction, knee flexion, knee abduction, contralateral pelvic drop, and lateral trunk flexion angles were assessed. Biomechanical data were compared between the 2 groups using a random-intercept linear mixed-models analysis. A significant group × time interaction effect was found for vertical GRFs (P = 0.01; change difference relative to baseline: 4.5%), knee abduction moment (P = 0.01; 14.8%), hip adduction (P < 0.01; 16.7%), knee abduction (P < 0.01; 13.8%), contralateral pelvic drop (P < 0.01; change difference: 26.6%), and lateral trunk flexion (P = 0.04; 20.37%) angles, favoring the global systems approach group after 6 weeks of training. Participants who trained using the global systems approach had significantly decreased lateral trunk flexion, hip adduction, knee abduction and contralateral pelvic drop angles, peak vertical GRFs, and peak knee abduction moment during a single-leg vertical drop jump compared with participants who trained with hip-focused exercises. Incorporating additional external resistance at the proximal trunk results in improved biomechanics compared with conventional hip-focused exercises.