Notebook computer use with different monitor tilt angle: effects on posture, muscle activity and discomfort of neck pain users

This study aimed to evaluate the posture, muscle activities, and self reported discomforts of neck pain notebook computer users on three monitor tilt conditions: 100°, 115°, and 130°. Six subjects were recruited in this study to completed typing tasks. Results showed subjects have a trend to show the forward head posture in the condition that monitor was set at 100°, and the significant less neck and shoulder discomfort were noted in the condition that monitor was set at 130°. These result suggested neck pain notebook user to set their monitor tilt angle at 130°.     

Quantitative posture analysis of 2D, 3D, and optical microscope visualization methods for microsurgery tasks

The purpose of this paper is to present a quantitative posture analysis of microsurgery tasks performed with different visualization methods. Microsurgery is traditionally performed using a binocular microscope; however surgeons are constrained by the optical eyepieces and are forced to assume joint angles that deviate away from neutral postures. This may be especially problematic for the neck and can increase surgeon discomfort and fatigue. Alternative visualization methods may improve surgeon posture by eliminating the constraints imposed by the microscope. This study examines both 2D and 3D heads-up displays as possible alternatives. Six subjects performed microsurgical tasks with each visualization methods for four hours. Quantitative posture analysis was done using Maxtraq software that tracks reflective markers on the subjects. The initial analysis of neck, upper arm, and elbow angles found significant differences between each display. A biomechanical analysis found that the differences in angles can result in loads on the neck joint that are twice as high in the microscope than the headsup displays. Although the alternative displays can result in better postures, improvements the display technology is needed to improve microsurgical task performance.     

Long-term effects of forearm support: computer users working at conventional desks

Recent research has demonstrated that forearm support might be preferable to working in the traditional "floating" posture for computer users. A previous field study in a call centre reported a significant decrease in discomfort following 12 weeks of using a conventional desk for forearm support. The aim of this follow up study was to determine the long-term effect (21 months post intervention) of forearm support on reported musculoskeletal discomfort in the previous sample of intensive computer users. METHODS: The follow-up sample consisted of 33 females and 2 males (59% of original group). Data were collected via self-report questionnaires and workstation assessments. RESULTS: Despite a significant reduction in discomfort for most body regions following the initial intervention, the only significant decrease in discomfort over 21 months was for the neck. Reported discomfort for all other body regions had decreased, apart from the shoulder in which there was a reported increase in discomfort. The results of this follow up study indicate that forearm support has a positive effect on the reduction of neck discomfort. The increase in shoulder discomfort indicates that a concave desk may be preferable to the conventional desk if the forearm support posture is to be adopted.     

Ergonomic evaluation of conventional and improved methods of aonla pricking with women workers

Conventional and improved methods of aonla pricking were evaluated ergonomically on an experiment conducted for 20 minute with women workers. The working heart rate, energy expenditure rate, total cardiac cost of work and physiological cost of work with conventional tools varied from 93-102 beats.min-1, 6-7.5 kJ.min-1, 285-470 beats, 14 -23 beats.min-1 while with machine varied from 96-105 beats.min-1, 6.5-8 kJ.min-1 , 336-540 beats, 16-27 beats.min-1 respectively. OWAS score for conventional method was 2 indicating corrective measures in near future while with machine was 1 indicating no corrective measures. Result of Nordic Musculoskeletal Questionnaire revealed that subjects complaint of pain in back, neck, right shoulder and right hand due to unnatural body posture and repetitive movement with hand tool. Moreover pricking was carried out in improper lighting conditions (200-300 lux) resulting into finger injuries from sharp edges of hand tool, whereas with machine no such problems were observed. Output with machine increased thrice than hand pricking in a given time. Machine was found useful in terms of saving time, increased productivity, enhanced safety and comfort as involved improved posture, was easy to handle and operate, thus increasing efficiency of the worker leading to better quality of life.     

Exposure assessment in different occupational groups at a hospital using Quick Exposure Check (QEC) - a pilot study

In order to test the feasibility and sensitivity of the ergonomic exposure assessment tool Quick Exposure Check (QEC), a pilot-study was conducted. The aim was to test QEC in different occupational groups to compare the exposure in the most common work task with the exposure in the work task perceived as the most strenuous for the neck/shoulder region, and to test intra-observer reliability. One experienced ergonomist observed 23 workers. The mean observation time was 45 minutes, waiting time and time for complementary questions included. The exposure scores varied between the different occupational groups as well as between workers within the occupational groups. Eighteen workers rated their most common work task as also being the most strenuous for the neck/shoulder region. For the remaining five workers, the mean exposure score were higher both for the neck and shoulder/arm in the most common work task. Intra-observer reliability shows agreement in 86% of the exposure interactions in the neck and in 71% in the shoulder/arm. QEC seems to fulfill the expectations of being a quick, sensible and practical exposure assessment tool that covers physical risk factors in the neck, upper extremities and low back.     

The effect of ergonomic intervention on neck/shoulder and low back pain

The aim of this study was to examine the effect of two types of ergonomic intervention on pain and pain-related disability in the neck/shoulder and low back regions. A cohort of 492 subjects of various occupations with non-specific neck/shoulder or low back pain was followed over a five to six year period. The study subjects were classified into four intervention groups: no ergonomic intervention, educational worksite intervention, workplace intervention, and combined workplace and educational worksite intervention. The group with no ergonomic intervention was used as the reference group. The changes in pain intensity and pain-related disability from baseline to follow-up in each of the three groups with intervention were compared to the changes in the reference group. During the follow-up, 39% of the subjects had received ergonomic intervention. The average change in pain intensity and pain-related disability was smaller in the educational worksite intervention group than in the reference group. The average reduction of pain intensity and pain-related disability did not differ between the two other intervention groups and the reference group. Thus, for subjects still at work, ergonomic intervention seemed to be ineffective for reducing neck/shoulder and low back pain and pain-related disability.     

The effect of visualization method on the performance of simulated microsurgery tasks

The operating microscopes may be a significant cause of fatigue and discomfort in surgeons. The need for the microscope to be placed over the operating field forces surgeons to remain at the microscope's eyepieces at an uncomfortable posture for the entirety of the surgery. This study compared the effects on microsurgical task performance for four visualization methods: a monocular microscope, a binocular microscope, a three-dimensional (3D) flat-panel television display and a two-dimensional (2D) flat-panel television display. Eleven subjects each performed two microsurgical tasks and their performance was documented by video camera. The statistical analysis performed indicated utilization of the microscope as a visualization method increased subject performance. No significant difference in performance between the 2D and stereoscopic visualization methods.     

Ergonomic evaluation in a values transportation company in Venezuela

The objective was to analyze the work activity and identify risk factors that could account for musculoskeletal disorders in the upper extremities, shoulder and neck of workers of a transport values company in Venezuela. The methods used were: collective interview, tasks observation, evaluation of posture with RULA method and evaluation of repetitive motions with the OCRA method. Five workstations were evaluated. Main problem perceived by workers was: exposure to chemical and biological hazards when handling paper money and coins; inadequate chairs and close supervision. The postures level risk was 1 or 2 for the RULA scale. Only two workstations showed ligth and medium risk level by OCRA method. Conclusion: The factors identified that could explain the musculoskeletal changes were: wrist repetitive flexion and extension, shoulder elevation, lifting weight above shoulder height, elbow repetitive flexion and extension, neck flexion, extended work journey, work overload, high responsibility and strict supervision by a video camera.     

Back pack injuries in Indian school children: risk factors and clinical presentations

The use of backpack increased substantially among the school children. Studies have shown that carrying a backpack cause to develop different symptoms of musculoskeletal disorders among the carrier of the backpack. In India there are fewer studies available in literature which explains the musculoskeletal discomfort among the school children. This study aimed at to find out the prevalence of different musculoskeletal problems among the school children. In a retrospective study data were collected for twenty two students. The main diagnostic criteria were pressure mark (redness or swelling) over neck and shoulder corresponding to the straps of the backpack, stooping posture while carrying the back pack, pain or stiffness in the neck, upper back and shoulders predominantly while carrying the back pack and absence of these symptoms during school holidays. Results revealed that pain in the upper back (40%), neck (27%) and shoulder (20%) were most prevalent body regions followed by forearm and wrist pain (7%) and low back (6%). Results further revealed that all the students participated in this study have a pressure mark over shoulder. 54.55% of the children were diagnosed with myofascial pain and rest with thoracic outlet syndrome.     

Biomechanical analysis of loading/unloading a ladder on a truck

Loading/unloading a ladder on vehicles are frequent tasks and involve overhead handling that may expose workers to risk factors of shoulder musculoskeletal disorders. The objective of the present study was to evaluate posture, forces required and perceived exertion when loading and unloading the ladder on a utility truck. Thirteen male overhead line workers from an electric utility in Brazil participated in this study. Shoulder elevation angle was measured using inclinometers. The required force to load/unload the ladder was measured by dynamometer. Subjective assessment of the perceived exertion was recorded to compare the exertion reported during the test conditions to the field conditions. The task of loading/unloading the ladder presented risks of shoulder musculoskeletal disorders (MSDs) to workers because it requires high levels of force (approximately 60% of the maximal force) combined with overhead posture of the shoulders (more than 100° from the neutral posture). Age and height presented to interfere in biomechanical risks presented in load/unload task. There was no significant difference between the subjective exertion during the test conditions and handling the ladder in the field. Ergonomic intervention is recommended to reduce these risks for shoulder MSDs.     

Co-variation in time between near-far accommodation of the lens and trapezius muscle activity

Visual strain and discomfort may contribute to the generation of work-related musculoskeletal disorders among e.g. computer workers. A positive correlation on a group level between eye-lens accommodation and trapezius muscle activity has been reported. In this study we investigated the possibility of a direct, fast, connection between lens accommodation and trapezius muscles activity. The subjects focused alternately on Near and Far targets, with a mean switch time of 5 s, through four different lenses. The cross-correlation, R(tau) was computed, between the time signals of accommodation and electromyography (EMG) from 23 subjects. In the overall mean R(tau) of 736 curves, a small but significant correlation peak (0.019) with a delay (of the EMG signal) of about 0.3 s, revealed a small common component in the two signals. Among the lenses, the positive lens (3.5 D), showed the highest correlation peak (0.040). The correlation may be caused by a direct "hard-wired" connection between the ciliary and trapezius muscles. But it could also be caused indirectly by the subject's need for a more stable head in a more demanding visual task. The latter is supported by the result that the correlation was the highest in the positive lens condition. The present correlation is however weak and it has probably a low practical importance.     

Participatory ergonomics and new work: reducing neck complaints in assembling

A participatory ergonomics approach is used to create a new work environment, which is aimed at reducing neck complaints in a cell phone assembly. The participatory ergonomics program included an initiative, problem identification, a selection of solutions, an implementation and evaluation. Twenty-eight women, all operators on an assembly line of cell phone boards, voluntarily participated in the design and evaluation of a device before implementing the device to all 215 employees performing that job. Prior to and after the intervention, RULA, comfort experiences and interviews were used. After introducing an adjustable angled small counter, these measurements showed both posture and comfort improvements. 90% of the 215 workers preferred the new work station and the neck complaints were reduced in 75% of the group. It also showed that the initial prototype needed to be modified as to reduce its sharp edges/compression points for the forearm. This project shows the importance of iterative testing and that an initiative by workers enlarges the chance of successful implementation.     

Child welfare workers go to court: The impact of race, gender, and education on the comfort with legal issues

This study examines perceptions of 425 public and private agency child welfare workers from one state in terms of their level of comfort with the court work components of their jobs, at baseline, which is after their initial training but before beginning their child welfare work, and again after six months on the job. Bivariate and multivariate analyses were undertaken. Bivariate analyses reveal that being older and male were associated with higher court comfort levels at baseline and at six months. Being white was associated with higher comfort levels at six months. In addition, private agency workers were more comfortable with court at baseline and six months. Workers with a social work education had higher court comfort levels at baseline and six months, when compared to those with criminal justice or other education. In the multivariate analysis, there were no significant differences in level of comfort with court work based upon worker characteristics at baseline. However, at six months on the job, predictors of comfort with child welfare work were being white and being male; having a social work education approached statistical significance. When change in comfort level was examined, the only significant positive predictor of court comfort was having a social work education.     

Associations between psychosocial risk factors and musculoskeletal disorders: application to the IT profession in India

The exponential growth of the information technology (IT) industry in India has been accompanied with a substantial increase in the reporting of work-related musculoskeletal disorders (WMSDs). The purpose of the current study was to identify and assess the contributions of prevalent psychosocial factors on perceived WMSD outcomes among IT professionals from India. About 77 IT professionals from India completed a survey set consisting of 26 question items from the Job Content Questionnaire and 3 separate question items pertaining to WMSD outcomes (pain/discomfort and psychological stress scores). The findings suggest prevalence of existing pain (shoulder/neck and low back) in more than one-fourth of the respondents. Additionally two-thirds of the respondents had never had any ergonomics awareness training. Co-worker support and psychological work demands were found to be the strongest contributors of psychosocial risk factors towards pain/discomfort and psychological stress outcomes. Findings from this study highlight the influence of certain psychosocial traits of the Indian IT workplace on perceived WMSD outcomes. There is a need to develop and implement intervention strategies to address these factors that may help lower the risk of work-related musculoskeletal pain.     

Relationship between construction workers' musculoskeletal disorders and occupational health service activities

Construction work consists of numerous factors that influence workers' occupational health and that load the musculoskeletal system in particular. Musculoskeletal disorders are responsible for over a third of all sick leaves lasting over nine days in the construction industry. Occupational health services (OHS) were organized for 85% of the construction workers in our study. The proportion of construction workers who had suffered from chronic or repetitive neck and shoulder, shoulder or arm, or low-back disorders was 55.6%, 44.8% and 42.1%, respectively. Those who felt that they had received enough information, advice or guidance from OHS concerning work posture, work performance or work tools were more often those who had not suffered from shoulder or arm disorders (60.9% vs. 39.1%, p=.024, respectively) or low-back disorders (63.6% vs. 36.4%, p=.034, respectively) during the last month than those who had. Those who had received enough support from OHS concerning maintenance of work ability were more often workers who had not suffered from low-back disorders during the last month than those who had (63.3% vs. 36.7%, p=.004, respectively). OHS should focus more on workers who would really benefit from their activities at a particular time and in a particular situation (primary, secondary or tertiary prevention) and who are themselves devoted to improving their health.     

Long periods with uninterrupted muscle activity related to neck and shoulder pain

The aim was to analyze the relationship between periods with uninterrupted neck muscle activity for ≥ 4 min and neck and shoulder pain. The trapezius muscle activity was recorded bilaterally on 40 young workers and students during a full shift. Neck and shoulder pain, mechanical work load and decision control were reported at the same time as the muscle activity recording and 6 months later. A dose-response relationship was found between uninterrupted muscle activity and neck and shoulder pain, with a ten-fold higher risk for the group with more than half, compared to less than a third, of the shift with uninterrupted muscle activity. Self-reported mechanical work load showed a small but protective effect related to pain. Gender and decision control did not emerge as important risk factors in this model. In conclusion, this study indicates that work or other exposures that contains long periods with uninterrupted neck muscle activity of 4 min duration or longer should be minimized to reduce risk of neck and shoulder pain.     

Physical and postural aspects of teachers during work activity

Studies indicate that teachers constitute a professional segment, in which the work characteristics and the demands originating from the act of teaching, favor the emergence of sickness, concerning physical or emotional aspects. The present work aimed to describe physical and postural aspects during the working activity of teachers. A total of 120 elementary school teachers (1st to 8th grade) took part in the survey. For data collection, a questionnaire was applied: it included personal and occupational information, perception of discomfort and being off work; physical strength activities; posture at work and physical conditioning activities. The average age of teachers of the present sample corresponds to 35,8 years. In relation to activities which generate more physical strength, the answer none of the activities was predominant with 30 answers; followed by writing on the board, standing up during the period of classes, explanation of the subjects, class elaboration, correction of homework and others. The area of the body with higher amount of occurrences and prevalent discomfort referred to the lower limbs and spinal cord. These data inform the necessity of investing in prevention programs for the teachers, in order to develop strategies into the organizational context and interventions at the work environment.     

Prevalence of musculoskeletal disorders among staffs in specialized healthcare centre

This study was conducted to investigate pervasiveness of the musculoskeletal disorder (MSD) among staffs in a specialized healthcare centre. Sixty-eight staffs from three departments namely Cardiovascular Lab (CVL), Nuclear Radiology, and General Radiography were recruited in this study. A modified Nordic Musculoskeletal Questionnaire (NMQ) was distributed among study population. The result shows that the prevalence of MSD was highest in lower back (88.2%), neck (76.5%) and shoulder (60.3%) for the past 12 months followed by lower back and elbow (44.1%), and wrist (39.1%) correspondingly, for the past 7 days. Present results suggest that healthcare professionals - radiographers, patient assistants and nurses incurs MSD risks through work tasks as well as psychosocial factors. These include awkward posture during patient handling, workload, work stress and time pressure. Therefore, an ergonomics improvement on the job design and workspace are needed in order to reduce the MSD risks.