bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromyographic and subjective evaluation of a wrist rest for VDT operators
Authors: Keller Erwin , Strasser Helmut
Published: May 2021

This study assessed the effects of a wrist rest for VDT operators based on an experimental investigation. Muscular strain associated with the working posture was measured continuously via electromyographic activities (EA) of 8 muscle groups which were involved in the working tasks. The electromyographic measurements yielded a clear systematical effect of the wrist rest while entering text using the 10-finger touch system. Values of the EA, as an indicator of physiological cost were essentially lower with the wrist rest. Working without the wrist rest is at least two times more strenuous than working with it. The differences are statistically highly significant. Less positive and less consistent results were found while working on the prefixed mouse pad of the wrist rest. Considering the influence of the working aid on entering text, the results of the subjective assessment after the tests corresponded well with the objectively measured physiological data. Whereas the working aid for entering text was assessed quite positively overall, the integrated mouse pad earned a clearly negative rating.
Epidemiological investigation of workdays lost due to VDT related injuries
Authors: Abib Abdillahi H. , Dutta Sourin P.
Published: May 2021

Several physiological factors, such as wrist, back, and neck injuries, and vision strain contributing to lost workdays in different types of industries using video display terminals (VDTs) were examined using multi-regression model. The developed linear multi-regression model showed that the presence or absence of neck injuries data gives the same result, although the data of neck injuries were highly correlated with dependent variable, workdays lost in comparison with other independent variables. The most important result from this model showed that the combination of back injuries and vision strain data have high correlation coefficient value. The position of worker's back affects his/her vision strain. Findings of this study show that wrist, and back injuries, and vision strain are the main contributors to the workdays lost. Since the numbers of workers using VDT are going up due to advanced technologies, the number of injuries related with VDT will go up dramatically if necessary actions are not taken.
Load heaviness and perceived weight lifted: Implications of human cognition for setting design limits in manual lifting tasks
Authors: Yang Yung-Nien , Karwowski Waldemar , Lee Yung-Hui
Published: May 2021

This paper examines interrelationships between the cognitive concepts of load heaviness, perceived weight lifted, and the size-weight illusion effect, and their importance for setting load limits in manual lifting tasks. Results of three related studies are presented, including: (1) a questionnaire survey of the perceived relationship between physical weights and subjective perception of load heaviness for a large subject population; (2) modeling of the above relationship using the fuzzy linguistic approach; and (3) laboratory examination of the perceived weights and load heaviness for five pre-weighted boxes. Thirty subjects who participated in the questionnaire survey, were asked to provide estimates of the perceived weights and corresponding linguistic classification of load heaviness, while lifting five pre-weighted boxes. The subjects had previously gone through another phase of the project where they had determined their maximum acceptable weight of lifting using the psychophysical approach. The perceived weights were not significantly different from the physical weights for the 'light' to 'moderate' categories of load heaviness. Furthermore, the concept of recommended weight limit (RWL) fell in the 'light' load category for which the subjects were good judges of load heaviness. The results of this study provide support for setting the lifting limits based on the RWL concept designed to reduce the risk of low back injury.
Geometric correction for a two-dimensional link segment model
Authors: Villalta Dino L. , Stevenson Joan M. , Pearce G. William , Brereton Lisa C.
Published: May 2021

The purpose of this study was to develop and validate a one camera analysis strategy to correct for the effects of perspective error due to out of plane rotation on the calculation of L4/L5 moment and compression and shear forces. A mathematical model was derived around the geometric relationship of a T-Bar shaped device and the measured camera to object plane distance. This geometric relationship was used to reorient a rotated subject back into the perpendicular film plane before calculation of joint moments and forces. Systematic errors (rotational perspective errors, forward/backward and side/side distances of subject from camera) and random errors (digitization error, anthropometrics, lifting techniques) were determined with maximum errors of 10.5%, within ±20 degree out of plane rotations. Results generally supported incorporation of a correctional device to extend the use of two-dimensional analysis strategies in industrial settings.
Office acoustics: Analyzing reverberation time and subjective evaluation
Authors: Strasser Helmut , Gruen Kristina , Koch Werner
Published: May 2021

Members of the design department in a medium-sized company were complaining to the management about the acoustic situation in new offices which adversely affected their personal well-being and their work performance. Therefore, a field study was conducted to analyze and evaluate the acoustic working conditions in the new offices and to develop improvements where necessary. Objective criteria for the evaluation of communication disturbances during meetings or telephone conversations were obtained by measuring the reverberation time in several offices. Questionnaires with unipolar or bipolar 4-step scales allowed a differentiated judgement of the current acoustic situation and its effects on the person or individual. Improvements of the acoustics were developed and cost-utility prognoses were made. The proposed solutions and their prospective acceptance rate among the employees were assessed before they were implemented.
Occupational injury in Swedish fishery: 1. Analysis of injury statistics
Authors: Törner Marianne , Nordling Per-Olov
Published: May 2021

The purpose of the present study was to make a thorough inventory of all serious accidents in Swedish fishery, reported to the Swedish Labour Market No-fault Liability Insurance, July 1983–June 1995 (431 cases, corresponding to a yearly rate of 12 per 1000 fishermen). No age group was over represented among the victims of such serious accidents. The most accident-prone activity was hauling of the trawl and the most common contacts in connection to this were getting jammed by a wire or hit by a falling object/receiving a blow by an object. The second most common activity at the time of accident was repair work/work by the wharf, often connected to the contacts pricks or cuts or falls. Falls to the same level was the most common contact over all, followed by falls to a lower level. The most frequent mechanism behind the accidents was working in an exposed position, and second most common was slipping. Hands and wrists were most commonly injured. The median value for sick listing due to serious injury in occupational accidents in fishery, was 48 days. Approximately one third of the victims suffered permanent disability (mean degree 7%). Trawl fishing was over represented in serious accidents. Half of the accidents occurred on deck. January had the highest portion of accidents (14%) followed by October and November (10% each). The most accident-prone time of day was 9.30–10.30 am.
Occupational injury in Swedish fishery: 2. Promoting implementation of safety measures
Authors: Törner Marianne , Cagner Mats , Nilsson Bertil , Nordling Per-Olov
Published: May 2021

Although fishery is a highly dangerous occupation, as reflected in accident statistics, preventive measures for improving safety on board the vessels are often neglected. The purpose of the present study was to develop, implement and evaluate a program for promoting implementation of safety measures in fishery. The safety program was based on a cost-benefit analysis including the following units: a) analysis of serious accidents in Swedish fishery during 1983–1995, b) cost analysis, specified for different types of accidents, c) inventory of safety measures including costs and accessibility, d) visits to 101 vessels with presentation of data acquired in a–c, followed by a participatory safety inspection of each vessel, and e) a six-month follow-up of the 101 visits and safety inspections. The average yearly rate of serious accident was 12 per 1000 fishermen. Economic consequences of different types of accidents in fishery were considerable for the victim, and under certain circumstances also for the rest of the crew. The safety inspections revealed 1427 safety or ergonomics deficiencies on board the 101 vessels (range 3–22 per vessel). The six-month follow-up showed that 80% crews had attended to one or more of the deficiencies identified at the safety inspections. Fifty-nine of the in all 160 safety measures taken constituted acquiring, or taking up the use of safety glasses or hearing protection. Apart from these, the measures taken were spread over most categories of risk factors. It is concluded that safety promoting methods based upon participation and expert support are cost effective.
Development of a hand tool work analysis method (HTWAM)
Authors: Peterson Peter , Wakula Jurij , Landau Kurt
Published: May 2021

The HTWAM method and software for the analysis of activities involving the use of hand-operated non-powered tools has been developed and tested in practice as part of the Eurohandtool project. The method was used to investigate 12 jobs in viticulture and 5 jobs in other sectors where hand tools are used. HTWAM showed itself capable of identifying weak points in a work system. HTWAM enables design engineers to perform work system analyses which can provide industry with recommendations for the ergonomic design of hand tools and can also give users information on the need for safety precautions and avoidance of health risks.
Ergonomic design criteria for pruning shears
Authors: Päivinen Minna , Haapalainen Mika , Mattila Markku
Published: May 2021

The principal design criteria for plier-like hand tools, using garden pruning shears as an example are presented. The criteria have been created especially for use with the quality function deployment (QFD) method, and thus the main criteria are divided into subgroups. Though studies in the area of hand tool ergonomics have been published, a detailed list of the factors which should be taken into consideration when one is designing new non-powered hand tools is still lacking. This comprehensive list can also serve as a checklist in the evaluation process for hand tools. Ergonomic design considerations can reduce force demands and fatigue and also improve the comfort of users.
The effects of restricted workspace on lumbar spine loading
Authors: Gallagher Sean , Hamrick Christopher A. , Cornelius Kim M. , Redfern Mark S.
Published: May 2021

Coal miners often handle heavy electrical power cables, weighing up to 10 kg per meter. These cables are manually lifted and attached to the mine roof to prevent damage from mobile underground equipment. Data suggest that workers who commonly perform cable-handling tasks experience a high rate of lost-time back injuries. In this study, six male underground miners performed a total of 12 cable-hanging tasks in standing, stooping, and kneeling postures, during which kinematic and ground reaction force data were collected. Reductions in vertical workspace were found to result in a linear increase in the peak moment experienced by the lumbar spine p < 0.05). In restricted postures, peak moments were not significantly different in stooping vs. kneeling postures (p > 0.05). Average lumbopelvic flexion during the tasks was highest in stooping conditions, followed by standing and kneeling exertions (p < 0.05). Implications of this data with respect to design of cable handling tasks are presented and discussed.
Effects of walking environments on the objective and subjective gait measures during dynamic task performance
Authors: Lu Ming-Lun , Bhattacharya Amit , Succop Paul A.
Published: May 2021

The objectives of this study were to evaluate the use of the center-of-gravity-based and center-of-pressure-based gait measures associated with loss of balance as well as the use of perceived sense of postural sway and instability (PSPSI) for the prediction of slip occurrence during dynamic task performance. The objective gait measures were determined by a multi-camera body motion analysis system and a strain gauge force platform. Twenty six trials performed by 21 subjects were collected for two walking environments in a laboratory-based experimental set-up. Two environments included the best (walking straight on a dry surface in good lighting) and the worst (walking straight on a slippery surface with a 2.3 Kg weight in the hand in poor lighting). Among the gait measures used in the study, it was found that the maximum distance between the center of pressure and the center of the base of support (OPmax) and the slide distance were the significant predictors of slip occurrence. An increase in the OPmax or slide distance indicates an increased likelihood of slip occurrence. The walking environment was found to have a significant effect on the PSPSI scale. It appears that the subjects were able to distinguish the difference in the walking environment but unable to perceive the potential hazards related to slips/falls during dynamic task performance. A comparison between the OPmax and slide distance (objective measures) and the PSPSI scale (subjective measure) can be used to predict a mismatch between the subjective perception of slip potential and the actual risk of slipping during task performance on a slippery surface.
Effects of standing and sitting postures on an isoinertial pulling task
Authors: MacKinnon Scott Netson , Stone Gareth Wesley
Published: May 2021

This study examined the effects that specific postures had on the neuromuscular activities of four muscles during an isoinertial pulling task. Ten male subjects volunteered to execute one-handed pulls at 15% of their body mass, at a frequency of 12 pulls per minute, for a duration of 12.5 minutes in both a standing and sitting posture. Electromyographical (EMG) activities of the posterior deltoid, trapezius, latissimus dorsi and erector spinae ( L 4/ L 5 level) were recorded by a portable data collection system using bipolar surface electrode configurations. Collected EMG data were subsequently analysed for differences in magnitude and rate of fatigue between conditions. Heart rates were also recorded for both conditions. Cardiovascular and neurophysiological responses provided no evidence of fatigue due to the execution of the task, suggesting that these workload and postures would be suitable for industrial applications. Analyses revealed significant differences between conditions in the level of activation for all muscles except the trapezius, suggesting that muscle recruitment is highly influenced by posture during common pulling activities. These findings support a conclusion that an operator performing repetitive submaximal (i.e. less than 15% of a subject's absolute body mass) pulling tasks would benefit from a workstation designed to accommodate standing and sitting postures in order to vary the manner in which agonist muscles are recruited.
The difference between peak force and build-up force exertion in elbow flexion
Authors: Voorbij Liek , Snijders Chris J.
Published: May 2021

The maximal peak and build-up forces at elbow flexion of 140° were measured without a wrist cuff. Peak force was found to be significantly higher than build-up force. The results established that peak force is more easiliy reproducible than build-up force. For women, the force studied did not decrease with age. The results of this investigation are believed to be useful for product designers in adjusting the product characteristics to deal with the loads exerted by users in peak force exertion.
Press operation: Workstation adjustment, working posture, and workers’ perceptions
Authors: Delleman Nico J.
Published: May 2021

At a press workstation eight industrial workers processed light-weight objects at six different combined adjustments of reach distance and working height. Working posture, workers’ perceptions, and task performance were measured. Two recommendations were formulated in order to minimize the load on the musculoskeletal system: (1) the maximum reach distance is not exceeded if the object can be placed in the stamp on the press as well as be removed without bending the trunk forward, and (2) the working height should be adjusted between 5 and 10 cm above elbow height.
An ergonomics approach to standing aids
Authors: Konz Stephan A. , Rys Margaret J.
Published: May 2021

Industrial work environments, such as warehouses, stockrooms, supermarket checkouts, and assembly lines, often require workers to stand for long periods of time within a small area without the capability for much movement. This study summarizes the different indices used to evaluate standing work and also evaluates the various standing aids, available at the present time, to reduce the standing stress. The subjective indices of standing are discomfort/pain in the torso and, especially, the legs and feet. Physiological indices are heart rate, skin temperature of the leg, and volume changes of the leg. Standing stress can be reduced by: (1) softer floors (i.e., mats), (2) better shoes, (3) foot rests, (4) walking, and (5) sit/stand chairs.
Ergonomic redesign of personal protective equipment for Korean policemen
Authors: Kwon Young G. , Kim Chol H. , Kim Hong K. , Byun Seong N.
Published: May 2021

Personal protective equipment (PPE) for Korean policemen that included protective clothing, a helmet, and a shield were evaluated and redesigned based on ergonomic principles. Major functional improvements were made by reduction of equipment weight, reduction of heat stress through improvement of equipment ventilation, and improvement of usability and safety. Redesigned prototype models were made for the protective equipments. The redesigned three components of PPE are helped to enhance work performance and job safety of police officers for anti-riot operation. Currently a helmet company is trying to export newly designed helmet to other countries.
Assessment of shoe-floor slipperiness with respect to contact-time-related variation in friction during heel strike
Authors: Grönqvist Raoul , Matz Simon , Hirvonen Mikko
Published: May 2021

The variation in utilized and available friction over shoe-floor contact time was determined in the presence of high- and low-viscosity contaminants. The objectives were to improve the validity of slipperiness evaluations and to find better criteria for safe friction during heel strike. The utilized friction coefficients for six shoe types were determined during gait-trials with male participants. The available friction coefficients of these shoes were measured with a test rig simulating heel slipping. The experiments were performed on a stainless steel floor with concentrated glycerol ('oily’ condition) and diluted glycerol (1:10 in water) as contaminants. It was hypothesized that any single friction measurement criterion would be an insufficient predictor for safe gait with no slip or with slip recovery, not leading to a fall. The results showed that both transitional friction (time-intervals from zero to about 250 ms of heel contact) and steady state kinetic friction (time-intervals from about 250 ms to 450 ms) properties in the shoe and floor interface play an important role in slipperiness measurement and slip/fall risk assessment. The role of static friction in the risk assessment remained unclear.
Effects of environmental and job-task factors on workers’ gait characteristics on slippery surfaces
Authors: Chiou Sharon S. , Bhattacharya Amit , Lai Chwan-Fu , Succop Paul A.
Published: May 2021

The objective of this study was to investigate the kinetic and kinematic aspects of slips associated with gait on a slippery surface under various environmental and job-task risk factors. Forty healthy industrial workers (age: 40.3 ± 14.9 years) participated in the study. Using a strain gauge type force platform and a video-based motion analysis system, kinetic and kinematic measurements of the subjects’ foot movements were obtained. Of all gait trials, there were 1558 slips (60.9%). Slips were likely to occur when subjects were negotiating a turning path and an oily surface. Greater anterior-posterior center of pressure (CP) excursion and maximum required coefficient of friction (RCOF) were found for oily surfaces compared to dry surfaces. Subjects changed their gait patterns by shortening their stride length, slowing walking speed, and decreasing heel contact angle in the poorly lit and slippery environment. Significant correlations were found between slip occurrence and anterior-posterior CP excursion, mean RCOF, sliding distance and sliding velocity, but not the coefficient of friction (COF) of shoes. In addition to good housekeeping and proper selection of floor materials and safety shoes, slip and fall prevention should include proper workers’ training in dealing with risk factors of slips and falls in the workplace.
The effect of drywall lifting method on workers’ balance in a laboratory-based simulation
Authors: Pan Christopher S. , Chiou Sharon , Hendricks Scott
Published: May 2021

Voluntary body movement can import a perturbation to the postural stability/balance of a human body. Heavy manual material handling such as drywall lifting may increase this perturbation. The objective of this laboratory-based study was to quantify workers’ postural stability while lifting drywall sheets through kinetic and kinematic analyses, and to identify the drywall lifting methods that caused the least perturbation on workers’ balance. Sixty male construction workers participated in this study. A simulated drywall-lifting workstation was built and all subjects performed one of the four randomly assigned lifting methods. Kinetic and kinematic measurements were synchronized and collected using a piezoelectric force platform and a five-camera motion analysis system. Both center-of-pressure (COP) and center-of-mass (COM) data were analyzed to assess workers’ postural stability. Univariate analyses and principal component analyses (PCA) were used to analyze 13 COP-based and 21 COM-based variables. Results from the univariate analyses and PCA significantly indicated that the three horizontal lifting methods created less perturbation than the vertical lifting method. Based on the results of this study and prior studies, it is concluded that horizontal lifting with both hands on top of the drywall appears to be the best work practice to reduce manual drywall handling hazards associated with fall potential and overexertion injuries.
Experimental evaluation of pressure distribution changes when using clinical support surfaces
Authors: Karwowski Waldemar , Rodrick David , Boratyn Grzegorz
Published: May 2021

The main objective of this study was to perform experimental evaluation of the human body-pad interface pressure distribution changes when using five different clinical support surfaces (pads). The studied pads included the support surfaces for: head, heel, hip, lower back, and multipurpose pad for relevant body segments. For each pad, experimental data from 44 independent trials were obtained using 22 participants (12 male and 10 female) who voluntarily participated in the study. To measure the human body interface pressure, an Advanced ClinSeat pressure measurement system was utilized. For pads of the head, heel, lower back, and shoulder, the participants were positioned on their back, while for the hip pad, the participants were placed on their side. The results showed that in all cases the recorded pressures were significantly lower when the participants used the comfort pads compared to the no-pad condition. Specific recommendations for improvements in the current pad design were provided.
Muscle strain of the hand-arm-shoulder system during typing at conventional and ergonomic keyboards
Authors: Strasser Helmut , Fleischer René , Keller Erwin
Published: May 2021

Manufacturers of ergonomic split keyboards promise maximum effectiveness and comfort as well as a reduction of physical complaints. In order to determine the positive effects claimed, a study was carried out during which 10 male subjects (Ss) participated in standardized working tests. They entered text into a PC, alternatingly using a conventional keyboard and an ergonomic keyboard. Electromyographic activity (EA) of 8 muscle groups was simultaneously recorded during altogether 6 working phases with a duration of 10 min, each. Measurements of the maximum activity, EAmax, via maximum voluntary contractions of the 8 muscles – which were necessary for calculating standardized electromyographic activity (sEA) used to represent muscle strain as a percentage – were always taken at the end of the experiment. Muscle strain varied from muscle to muscle but the level of the sEA-values for the different muscles was reproducible and stable. Also, activation of most muscles acting on the shoulder, upper arm, forearm, and the hand showed differences which, though small in amount, could be statistically secured and associated with the keyboard type. The ergonomic design of the tested keyboard led to objectively verifiable and plausible reductions of muscle strain.
Maximum one-handed pull force and its relation to shoulder geometry
Authors: Gielo-Perczak Krystyna
Published: May 2021

The current study proposes a method of geometrical description of the shoulder articulating surfaces in order to deduce an unrecognized relationship between shoulder geometry and strength during a one-handed pulling task. The paper reports the results of a study of the strength of 12 participants during one-handed pulling correlated with the geometries of their shoulder joints derived from magnetic resonance imaging (MRI) scans. The measurements of a mean force during pulling were recorded when an upper arm was adducted in the frontal plane from 5 to 30 degrees during maximum voluntary contraction (MVC). It was observed in the study that an area determined by the height and width of the glenoid fossa closely relates to the mean force during pulling.
Noise and muscle contraction affecting vigilance task performance
Authors: Button Duane C. , Behm David G. , Holmes Michael , Mackinnon Scott N.
Published: May 2021

The objective of this study was to determine the effects of muscle contraction intensity, neuromuscular fatigue, and noise on vigilance performance. Dependent variables included simple (reaction time and movement time) and complex (video game: Tetris) vigilance tasks (SVT and CVT respectively) and maximum voluntary contraction (MVC) force and activation. Vigilance tasks and MVC were randomly allocated to 5 minute blocks during a pre-test. Following the pre-test, the tests were again randomly allocated within three, 15 minute testing sessions over 65 minutes, while 1) being exposed to high (95 dB (A)) or low (53 dB (A)) levels of noise, and 2) performing muscle contractions at 20% and 5% of MVC, or no contractions. Ninety-five (95) dB (A) noise increased (p ≤ 0.01) SVT (reaction time and movement time combined) by 11.2% and decreased (p ≤ 0.01) CVT by 20%. Both 20% and 5% MVC impaired SVT and CVT to a similar extent, while no changes were seen with no contractions. Furthermore, neuromuscular fatigue had no apparent effect on vigilance task performance. These findings suggest that the distraction of noise and divided attention between muscle contraction and a vigilance task decreases performance.
Muscle strain and perceived exertion in patient handling with and without a transferring aid
Authors: Kothiyal Kamal , Yuen Tai Wai
Published: May 2021

This study presents the results of an evaluation of a patient handling aid commonly used for transferring patients from bed to toilet or other type of chairs. The results of the study showed that use of the patient handling aid (sling) increased the rate of perceived exertion at the lower back and the shoulder. Investigation of the muscular activity using electromyography in the shoulder and the lower back regions revealed that there was significant increase in the erector spinae activity in the lower back region. The increase in the back strain in the sling transfer was related to the increase in lumbar flexion resulting from the relatively smaller size of the sling. Trapezius muscle on the other hand did not indicate any difference in activity. The results of this study indicate that for positive outcomes there is a need for ergonomic evaluation of the sling and the postures adopted by the patient handler while transferring the patient with the sling.
Prevalence of musculoskeletal symptoms among Hong Kong nurses
Authors: Yeung Simon S. , Genaidy Ash , Levin Linda
Published: May 2021

This study aims to investigate how different prevalence selection criteria affect the prevalence rates of musculoskeletal symptoms in single and multiple body regions among female nurses working in a hospital setting in the Hong Kong area. Results showed that the 12-month prevalence rate for each body region was consistently higher than the 1-month prevalence rate. The 1-month prevalence rate for lower back was 59%, and 30–39% for lower extremity, upper back and neck, and the corresponding values for 12-month prevalence rates were 98% for lower back, and 89–91% for lower extremity, upper back, and neck. A similar trend was recorded for the 12-month prevalence of musculoskeletal disorder cases (MSD) (a case was defined as a reported symptom by the study participant, which is characterized by high frequency and/or intensity symptom) in the lower back (42%), knees/lower legs (30%), upper back (23%), hips – thigh (21%), and shoulders (21%). The 12-month MSD prevalence rates for lower back and one other body region ranged from 6% to 17%. The prevalence of MSD in the lower back – knees – and hips or ankles ranged from 11% to 12%. In addition, MSD cases in the lower back regions were significantly associated with those in the upper back, hip, knee, and hand regions. It is concluded that musculoskeletal symptoms are prevalent in single and multiple body regions, and symptoms originating from one body region may be associated with those in other body regions. A holistic approach in the evaluation and prevention of musculoskeletal problems for high-risk occupations is needed.
Economic fluctuations affecting occupational safety. The Spanish case
Authors: de Ercilla Fernando Terrés , Mondelo Pedro Rodríguez , Casado Enrique Álvarez , Vilella Emilio Castejón
Published: May 2021

Safety science, in its multidisciplinary approach, has been enriched by the contributions of economic science practically from the beginning of its development. In this area of knowledge, a particularly relevant subject matter is the impact of economic fluctuations or cycles over the effect indicators of safety (incidence indexes). Two theories have been put forward from the field of safety: intensification theory and vulnerability theory. In this paper, the authors propose an integrative theory and analyse the Spanish situation in the light of this new theory, validating its application.
Developing an effective diagnosis for safety improvement in steelworks
Authors: Hale A.R. , v.d. Waterbeemd H.A. , Potter R. , Heming B.H. , Swuste P.H.J.J. , Guldenmund F.W.
Published: May 2021

The paper describes the methods used for a study of the safety management system and culture of a cold rolling mill in a steel plant. It uses data from diverse sources which can be validated against each other and combined to produce a rich picture of the current risk control system and its shortcomings. The paper also describes the proposed improvements and what the plant chose to implement. This step also throws light on the culture of the plant.
An index for back pain risk assessment in nursery activities
Authors: Taloni Silvia , Cassavia Giovanni Carlo , Ciavarro Giuseppe Luca , Andreoni Giuseppe , Santambrogio Giorgio Cesare , Pedotti Antonio
Published: May 2021

Back pain is one of the most significant socioeconomic problem in industrialized countries. Its origin is multifactorial, including physical, psychosocial and individual risk factors. Among the working population, nursery teachers are highly exposed to back pain diseases, but not many studies have dealt with this problem. So a suitable quantitative index is proposed, based on an unobtrusive video-analysis of established motor-tasks. In particular five nursery teachers were asked to perform lifting and lowering movements placing their feet at two different distances from a weight (a toy pet loaded with 8 kg, simulating a child) with different strategies (flexed, partially flexed and extended legs). The index is based on the idea that a greater trunk inclination angle determines increased loads on the lumbar spine, and so an augmented probability of spinal disorders. To validate our protocol, the same data were analyzed through a 3D biomechanical model (gold standard method), which computes the loads on L3-L4 intervertebral disc. Data show a good correspondence between the risk level suggested by the index and the one indicated by the mechanical loads: the antero-posterior shearing forces and the values of index coherently increase with the reduction of leg flexion.
Classification of jobs with risk of low back disorders by applying data mining techniques
Authors: Zurada Jozef , Karwowski Waldemar , Marras William
Published: May 2021

Work related low back disorders (LBDs) continue to pose significant occupational health problem that affects the quality of life of the industrial population. The main objective of this study was to explore the application of various data mining techniques, including neural networks, logistic regression, decision trees, memory-based reasoning, and the ensemble model, for classification of industrial jobs with respect to the risk of work-related LBDs. The results from extensive computer simulations using a 10-fold cross validation showed that memory-based reasoning and ensemble models were the best in the overall classification accuracy. The decision tree and memory-based reasoning models were the most accurate in classifying jobs with high risk of LBDs, whereas neural networks and logistic regression were the best in classifying jobs with low risk of LBDs. The decision tree model delivered the most stable results across 10 generations of different data sets randomly chosen for training, validation, and testing. The classification results generated by the decision tree were the easiest to interpret because they were given in the form of simple 'if-then' rules. These results produced by the decision tree method showed that the peak moment had the highest predictive power of LBDs.
Manual materials handling implications of global changes in work
Authors: Drury C.G.
Published: May 2021

The world of work is changing, driven partly by such forces as globalization, changed workforce demographics, increased work intensity and pervasive computing. These changes in turn have implications for manual materials handling systems and how they will affect the workforce in the future. This paper argues that most of the changes imply more diversity of both jobs and of those performing the jobs. Increased diversity means that task demands are more likely to exceed human capabilities, so that ergonomics will be needed more in the future. Strategies for responding to the changes at the levels of the profession and the enterprise ergonomics function are presented.
Self-evaluation of biomechanical task demands, work environment and perceived risk of injury by nurses: A field study
Authors: Karwowski Waldemar , Jang Ren-Liu , Rodrick David , Quesada Peter M. , Cronin Sherill N.
Published: May 2021

A field study was conducted to determine how nurses regard their working environment in terms of perceived physical (biomechanical) tasks demands, work ability requirements, perceived effort, risk of injury/illness, and assessment of working conditions (physical environment). Twenty-one participants (7 registered nurses and 14 nurse assistants), currently working at a southern United States hospital in a mid-size metropolitan city, participated in this study. The study classified two hundred nursing activities into 18 task categories. A comprehensive questionnaire for subjective evaluation of work environment was applied. A multiple stepwise regression modeling technique was then used to investigate plausible relationships between several dependent variables based on the questionnaire outcomes and the perceived nursing task demands (independent variables). The dependent variables included the following: 1) reported low back discomfort (RLBD), 2) perceived muscular effort (PME), 3) perceived risk of musculoskeletal injury/illness (PRMII), 4) dissatisfaction with the perceived comfort of working conditions (DWC), and 5) dissatisfaction with the perceived safety and health of working conditions (PSHWC). The results revealed that working with fixed lower back postures was the significant predictor for PME (R2 = 0.55), PRMII (R2 = 0.475), and PSHWC (R2 = 0.519). In addition, the study found that walking and working with fixed lower back positions were significant predictors for DWC (R2 = 0.525). Furthermore, the perceived demand for lifting, lowering, and carrying heavy objects during a working day was the significant predictor for RLBD (R2 = 0.611).
Mechanical considerations for biomechanical glenohumeral joint modeling
Authors: Gielo-Perczak Krystyna
Published: May 2021

The strength of the upper extremity in the frontal plane is two times less than in a sagittal plane. Shoulder strength is a limiting factor in upper extremity exertion capability. The purpose of this study was to analytically explain and present the influence of glenoid curvature and the middle deltoid muscle attachment on vertical translations of a humeral head in the superior-inferior direction during elevated arm positions. The paper reports the magnetic resonance results of the glenoid shape of 12 subjects and confirms variability in tangent inclinations and distances of the tangents from the lateral deltoid attachment. It was found that the largest translations of the humerus are during abduction ranging from 0° to 40° and from 140° to 170°. This suggests that both initiation of a movement and raising an arm above shoulder height are critical. The study confirms that the bone surface contacts as well as the muscles are important factors in stability and joint strength. It may provide new information on the sensitivity of the glenoid shape on glenohumeral joint stability and on individual arm strength.
Biomechanical modeling for understanding of low back injuries: A systematic review
Authors: Davis Kermit G. , Jorgensen Michael J.
Published: May 2021

With the enormous burden that low back pain has on society, researchers are constantly attempting to find effective evaluation techniques that identify mechanisms of injury. One of the more widely used methods utilized to understand the physical loading on the lumbar spine is biomechanical modeling. While there are a wide variety of spine load models, they all operate under a load-tolerance premise. The current review discusses key considerations that current and future biomechanical models need to take into account such as injury site, torso posture, torso dynamics, individual differences, gender and age differences, and detailed anatomy. A detailed description of the potential injury sites and nociception reveals the importance of understanding the complexity of the spine and the necessity of looking beyond the intervertebral disc. This review provides a broad overview of current models, including a description of the prominent spine load models in the literature. Finally, future directions of spine biomechanical models are discussed, providing insight to potential new frontiers to increase our understanding of how low back injuries and pain is initiated.
Industrial production of food: Risk surveys of three manufacturing systems from an occupational safety perspective
Authors: Willquist Petra , Örtengren Roland
Published: May 2021

Industrial production of food is a branch of industry suffering from many occupational accidents. This paper aims at identifying risks and safety measures in three production systems within this industrial sector. A qualitative exploratory case study with three embedded sub cases was performed. Methods for safety analysis were utilized for data collection and analysis. Risks were mostly handled by reactive technical solutions such as physical barriers and organization of working methods, separation in time and preventive maintenance. Still, relying on human conduct was customary. It was found that there was a lack of overview of the system which gave rise to safety problems. Furthermore, the focus was on product and not production, meaning that production development is handled on operational level, leading to ad-hoc solutions. Safety of machines and automated systems are still not satisfactory when it comes to tasks outside the planned work such as production disturbance handling and cleaning. Documentation, education and information are not used as much as one could expect to improve safety. The results are compiled in a table showing sources of accident risk, exposure control and control of human conduct.
Physiological fatigue limit of combined manual materials handling tasks
Authors: Iridiastadi Hardianto , Aghazadeh Fereydoun
Published: May 2021

The present study is aimed at determining Physiological Fatigue Limit (PFL) values for Combined Manual Materials Handling (CMMH) tasks while handling Maximum Acceptable Weight of Lift (MAWL), and to compare the PFL of handling MAWL and PFL values expressed as percentages of treadmill aerobic capacity and values expressed as percentages of CMMH aerobic capacity. Results of the study show that PFL values of CMMH tasks, on the average, are approximately 25% of treadmill aerobic capacity and 35% of CMMH aerobic capacity. This difference is statistically significant. It is suggested that the PFL figures used for designing manual materials handling jobs should be based on physiological data collected using real or simulated manual materials handling tasks rather than standard tasks of treadmill, etc.
Task variability and extrapolated cumulative low back loads
Authors: Dunk Nadine M. , Keown Kiera J. , Andrews David M. , Callaghan Jack P.
Published: May 2021

The aim of this research was to examine the repeatability of task cycle loading to assess the feasibility of data extrapolation approaches for calculating a shift cumulative exposure. The number of trials of a lifting task that would be necessary to provide a stable estimate of the cumulative low back loads sustained during manual material handling tasks throughout a normal working day was examined. Both a lab-based experiment (n=10 males) with a highly constrained task, and an externally paced industrial sample performing their regular workday task (n=8 males), were studied. Both study groups were videotaped while performing lifting trials and 10 consecutive trials were chosen for biomechanical analysis. Cumulative loading variables were determined for each lift and accumulating means were calculated for comparison with the gold standard, or criterion measure, which was the average of all 10 trials. It was found that a minimum of 4 trials was required to provide a stable estimate of cumulative loading in the lab-based task. The lab data were tightly clustered with an overall average coefficient of variation of 5.7%. Data obtained in the industrial setting were more variable with an average coefficient of variation of 24.8%. When individual lifting cycles were extrapolated to an 8 hour shift exposure, cumulative compression for the industrial task varied by 6.3 MN·s (range=15.2 to 21.5 MN·s) for one subject and for the constrained laboratory task it varied by 5.0 MN·s (range=32.0 to 37.0 MN·s). These results highlight the importance of using multiple cycle samples to establish a stable estimate of cumulative loading prior to extrapolating for a shift exposure.
Evaluating human body area factors from digital images: A measurement tool for a better evaluation of the ergonomics of working places
Authors: Calvino Francesco , La Gennusa Maria , Nucara Antonino , Rizzo Gianfranco , Scaccianoce Gianluca
Published: May 2021

The evaluation of comfort conditions of people in confined environments requires a knowledge of the human body's radiation data. This is essentially represented by the projected area of the body in a given direction. From this factor, other important parameters can be computed, such as projected area factors and angle factors. Presently, these parameters are evaluated using graphs deriving from a pioneering field study carried out by P.O. Fanger for which a piece of apparatus using mirrors and weight operations on film negatives is used. Obviously, these graphs, apart from referring to a limited number of subjects, also involve some reading errors. With the aim of enlarging the number of experimental cases and in order to provide a simplified method of making measurements, this work proposes a new experimental procedure based on digital images of the human body which are processed using a computer-based system. The first part of the paper is dedicated to the description of this procedure and to some early comparison with data found in the literature on the subject. The second part concerns the introduction of a new method for computing the effective area of people, starting from the projected areas taken by means of the present apparatus.
Musculoskeletal disorders of the upper extremity associated with computer work: A systematic review
Authors: Village Judy , Rempel David , Teschke Kay
Published: May 2021

The epidemiological literature is critically reviewed to evaluate the evidence supporting a causal relationship between computer work and musculoskeletal symptoms and disorders (MSDs) of the hand, wrist, forearm, and elbow. Since 1990, 33 publications were found that met the selection criteria –11 were prospective in design and 22 were cross-sectional. All prospective studies that measured extent of computer use found a positive association between computer work and upper extremity musculoskeletal symptoms. The two prospective studies to conduct physical examinations both found a relationship between hours of computer use and increased risk of upper extremity diagnoses. Of the 22 cross-sectional studies, 17 studies found positive associations. Two of the five studies reporting no association found increased risks of certain disorders under certain combinations of computer use and other factors. The remaining three studies were limited by either a small sample size or low variation of computer use hours within the study population. We conclude that there is consistent evidence of a positive relationship across numerous prospective and cross-sectional studies with increased risk most pronounced beyond 20 hours/week of computer use or with increasing years of computer work. The disorders confirmed with physical examinations are wrist tendonitis and tenosynovitis, medial and lateral epicondylitis, and DeQuervain's tenosynovitis. The risk of carpal tunnel syndrome is increased with use of a computer, especially with mouse use for more than 20 hours per week.