bluuebunny/crossref_metadata_2025 huggingface dataset:
Postural stability assessment during task performance
Authors: Bagchee Angshuman , Bhattacharya Amit , Succop Paul A. , Emerich Ronald
Published: May 2021

The methodology described here presents quantitative measures of estimating the severity of postural instability based on the proximity and spread of body sway in relation to the basal area of support. A simplified functional basal area of support is determined based on the maximal forward reaching ability of the subject. Three non-dimensional indices for quantitating the potential of postural instability are introduced. Application of this method is illustrated through an experiment with ten healthy industrial workers performing four different tasks. The results indicate that these indices are reproducible, sensitive to task performance and can be utilized to estimate the postural stability associated with each task. Application of this method would include the identification of factors, both intrinsic and extrinsic, that contribute to the maintenance of postural balance during task performance. Interventions can then be evaluated using this method.
Models for lifting load capacity of Indonesian population
Authors: Aghazadeh Fereydoun , Waly Sherif M. , Santoso Dedik S.
Published: May 2021

Regression models were developed to predict the maximum acceptable weight of lift (MAWL) for Indonesian population based on anthropometric and job related variables. Job related variables including lifting frequency, lifting height, and vertical distance of lift and 16 anthropometric variables were used in this study. A comparison between the MAWL obtained from this study, NIOSH RWL and the predicted MAWL of U.S. workers were conducted. RWL were much lower than the MAWL for both Indonesian and U.S. workers. Also, the Indonesian workers had higher MAWL compared to the U.S. population.
Effects of environmental and task risk factors on workers' perceived sense of postural sway and instability
Authors: Chiou Shiowyi , Bhattacharya Amit , Lai Chwan-Fu , Succop Paul A.
Published: May 2021

The objective of this study was to evaluate workers' ability to detect changes in postural balance using a short questionnaire -- the perceived sense of postural sway and instability (PSPSI) scale. Ratings of perceived sense of postural sway and instability for four simulated tasks were obtained from fifty-two healthy industrial workers and compared with objective measurements determined by a strain gauge type force platform. The simulated tasks were performed under various experimental conditions that may influence postural stability. It was found that subjects were able to perceive the changes in postural sway and instability due to the modification in peripheral vision, environmental lighting, workload, and surface firmness, as reflected by their PSPSI ratings. Results from this study indicate that the PSPSI scale is a promising tool, which provides a simple and valid method to evaluate the potential for loss of balance in the workplace.
A study of musculoskeletal strain experienced by nurses
Authors: Hernandez Luz , Genaidy Ash , Davis Sue , Guo Lin , Alhemoud Ali
Published: May 2021

This study was conducted to determine whether the activities performed by fourteen registered nurses subjected the different body joints to varied levels of musculoskeletal strain. While the present study confirmed the presence of significant lower back problems among nurses, the findings strongly suggest that nurses experienced significant musculoskeletal strain in other body parts/joints. In general, the lower back, neck, shoulder and wrist/hand recorded the highest scores in terms of frequency and severity of musculoskeletal strain. Discomfort increased significantly during the course of time for all body parts. A practical method was proposed for the evaluation of musculoskeletal discomfort on the basis of the Borg scale. The 0-2 range is suggested as a green zone where no action is required. The 3-5 is presented as a yellow zone where caution should be in place and an action plan should be formulated to monitor the jobs in question in the intermediate and long terms. This zone is preserved for cumulative-based ergonomic problems. Finally, the 6-10 range should be regarded as a red zone where an immediate action should be in place because musculoskeletal troubles are around the corner and could occur any time. Again, the red zone is expected to cover acute-based ergonomic deficiencies.
The ability of background factors, work practices, and psychosocial variables to predict the severity of musculoskeletal discomfort
Authors: Baker Nancy A. , Jacobs Karen , Carifio James
Published: May 2021

This study identified which combination of background factors, work practice, and psychosocial variables could discriminate most accurately between individuals with mild, moderate, or severe musculoskeletal discomfort in a population of 155 customer service representatives of a telecommunications company. These risk profiles were obtained for overall upper body musculoskeletal discomfort, as well as for each individual body part (neck, shoulder, elbow, wrist/hand, and back). Results of discriminant analyses suggested that risk profiles were different for each body part and could accurately classify from between 50 and 100% mild, moderate, or severe discomfort categories. These risk profiles were all highly significant (<0.01). This research identified the amount of social support, job variety, and skill utilization on the job as the psychosocial variables most often associated with musculoskeletal discomfort in this population.
Prediction of metabolic costs, psychological feeling and lifting workload limits for Chinese population
Authors: Zhang Zhijun
Published: May 2021

This study examined the effects of lifting technique, lifting frequency and lifting weight on oxygen uptake, pulmonary ventilation, heart rate, and rating of perceived exertion of the Chinese population. The physiological and psychological responses increased significantly with repetitive lifting workload. The workload was calculated from several lifting task characteristics including lifting frequency, lifting weight and lifting distance. The regressive formulas were produced statistically. The metabolic costs and psychological feeling could be reliably predicted from repetitive lifting workload and lifting technique. The workload limits of specific lifting tasks could be estimated by comparing predicted metabolic costs and psychological feelings with relevant available physiological and psychological tolerances of Chinese population. The study further revealed that lifting technique significantly affected lifting capacities.
The effects of handwheel position on torque production capability of operators
Authors: Wood Kathleen K. , Schulze Lawrence J.H. , Chen Jen-Gwo , Cleveland Theodore G.
Published: May 2021

A study was conducted to determine how the position of the handwheel affected the amount of torque applied by an operator. Data were collected at a series of wheel heights and distances. Results indicate that the main effects of gender, wheel height, and wheel distance, and the interaction between gender and wheel distance were statistically significant. No practical differences in torque production among the 5 wheel heights used in this investigation were found. A strong correlation existed between torque production capability and a handwheel height of 101.6 cm and weight of the male participants.
Use of human expertise in the evaluation of manual lifting activities
Authors: Genaidy Ash , Beltran Jose , Yeung Simon , Karwowski Waldemar , Succop Paul , Huston Ron , Stambough Jeffrey
Published: May 2021

The primary objective of this research is to determine whether or not worker expertise can be used to evaluate industrial lifting activities in order to prevent lower back injuries in the workplace. Twenty-two professionals and twenty-two skilled laborers participated in the study. The results obtained in this study indicate that it may possible to use personal knowledge and experience in evaluating physical tasks such as lifting. Furthermore, there was no difference between professionals and skilled laborers in terms of the cognitive patterns relating input to output variables. This provides preliminary evidence that the logic of experienced workers is as good as that of professionals. In the open lifting model examined in this study, it is clear that the weight of load is perceived by the study participants as the most important variable in evaluating lifting activities and is in agreement with findings in the published literature. In the closed loop model, perceived risk emerges as an important variable in determining the effort level exerted during lifting activities, even more important than the weight of load.
Ergonomic design of non-powered hand tools: An application of quality function deployment (QFD)
Authors: Haapalainen Mika , Kivistö-Rahnasto Jouni , Mattila Markku
Published: May 2021

Quality function deployment (QFD) is a design method that can be used to improve the quality of products. A QFD application aimed at improving the ergonomic quality of pruning shears is presented. User needs for pruning shears, as well as the design aspects which have the greatest influence on the ergonomic quality of pruning shears were defined. This information was entered in the house of quality (HOQ), which is a QFD tool. The HOQ results are represented in the form of relative importance of design aspects. The results of HOQ and user interviews show that both the approaches give the most important design aspects that are same. QFD is considered a suitable method for the ergonomic design of hand tools. The QFD application provides valuable information in the design process for hand tools and it can be used in the decision-making process during the design of hand tools.
Job strain and musculoskeletal disorders of Italian nurses
Authors: Camerino Donatella , Cesana Gian Carlo , Molteni Giovanni , De Vito Giovanni , Evaristi Cinzia , Latocca Raffaele
Published: May 2021

A sample of 1159 nurses was recruited to identify the physical and psychosocial factors associated with musculoskeletal symptoms. Environmental and task conditions were investigated to determine the presence and intensity of physical risk. Musculoskeletal disorders were investigated by a standardized questionnaire, while perceptions of stress were evaluated with a questionnaire derived from the Job Content Questionnaire. Postural and lifting risk identified in different wards was medium. Prevalance of back symptoms in females, compared with a control group, was significantly greater for all rachis tracts in all age groups. The prevalence was greater than controls only in the younger males age groups. A high prevalence of lumbar and thoracic musculoskeletal disorders was associated with job seniority, high "physical efforts" and "psychological job demand" in the female group. Reported disabilities resulted associated with "job seniority", "physical effort" and the perception of reduced "social support" in female groups.
Work physiology and ergonomics in Germany: From the past to future challenges
Authors: Strasser Helmut
Published: May 2021

Fundamental knowledge of anthropometric dimensions and biomechanical properties, of the capacities, as well as limitations, of the human sensory organs and the hand-arm system, i.e., comprehensive work-physiological knowledge of the characteristics of the human organism, always was, and will still in the future remain, a prerequisite for the truly ergonomic design of workplaces and work tools. Especially in Germany, work physiology represents the nucleus of today's work science or ergonomics. Besides the tasks and objectives of work physiology in ergonomics education, the principles of work-physiological research approaches are described. When evaluating workplaces and work tools, measuring physiological cost which the organism or the organs have to pay must be quantified. Similar to heart rate increases above the resting level associated with whole-body dynamic muscle work, the physiological cost of the muscles involved in repetitive manual movements, and the operating of hand-held tools or computer input devices can be measured via multi-channel electromyography. Physiological costs of sound exposures can be quantified in temporary hearing threshold shifts and their restitution, and physiological cost to the eyes is represented, for example, in varying levels of accommodation, adaptation, and fixation. Thinking in terms of physiological cost of work guarantees safe guidance in order to achieve human-oriented working conditions. According to recent developments in acts, ordinances, directions, and regulations in Europe, ergonomics has gained a high rank, but successful ergonomic interactions depend on comprehensive knowledge and experience, and require core competency in work-physiology as well as in ergonomics work design.
The effects of hammer design and hammering surface orientation on task performance
Authors: Karwowski Waldemar , Mattila Markku , Quesada Peter M. , Kwon Young-Guk , James David
Published: May 2021

This study examined the effect of hammer design parameters on task performance, operator physiological responses, perceived rate of exertion, task completion time, task accuracy, and user preference for hammering in the vertical (wall) and horizontal (bench) surface orientations. Two hammers used in the study differed with respect to their weight and softness of the handle grip. Ten male subjects participated in the laboratory experiment. The results showed that hammer design differences affect hammering task performance and perceived physical exertion. In general, the horizontally-oriented hammering task was faster than vertically-oriented hammering. However, task accuracy (i.e. number of nails hammered straight) was not statistically different with respect to either hammering orientation or hammer design. Subjects identified handle design, weight, and hammer mass distribution as critical factors that affect hammering task performance.
Ergonomics evaluation of equipment adjustability for Mexican-American population
Authors: Quintana Rolando , Alonso Jose A.
Published: May 2021

The effects of lack of equipment adjustability on nominal ranges of motion of upper body limbs for industrial sewing operations were studied, with a particular focus on Mexican-American males. Key upper body-segments of an industrial sewing operation were marked and analyzed using cinematography for a random pool of male workers descending from northern Mexico. Experimental results revealed that the worker's posture was affected by the adjustability of the sewing equipment, which was designed for the 5th to the 95th percentile of the US population. The awkward postures in turn affected the mean angular range of motion for the body-segments studied. As a result, there was a significant percentage of the available pool of worker's that may face occupational disorders, in spite of the fact that the equipment is adjustable, albeit from the 5th to the 95th percentile of the US population. These findings are particularly important to companies whose workforce is predominantly from populations that do not fit the US population profile. An adjustability index tool was developed as an equipment purchase/design tool that quantifies the percentage of the available pool of workers at risk of occupational disorders due to improper postures resulting from lack of adjustability. Finally, a cost framework is presented for choosing equipment that minimizes internal and external costs associated with equipment adjustability.
Postural stability during task performance on elevated and/or inclined surfaces
Authors: Bhattacharya Amit , Succop Paul , Kincl Laurel , Lu Ming Lun , Bagchee Angshuman
Published: May 2021

The purpose of this study was to subjectively and objectively evaluate the postural stability of forty industrial workers while performing simulated industrial tasks on inclined and elevated surfaces under various combinations of environmental lighting and noise distraction conditions. The results suggest the following ordering for the effects of risk factors on objective measure of postural balance: (1) environmental lighting, (2) elevation of standing surface, (3) gender, (4) inclination of standing surface, (5) age. The task performed would be ranked highest had the data been analyzed across the three tasks. The postural sway length significantly increased with increasing elevations and inclination angles for the stationary and bending tasks implying body's perceived risk of fall deployed increase in postural muscle contraction. This compensatory mechanism indicated by increased sway length actually did reduce postural sway amplitudes with increasing elevation but for increasing inclination the postural sway amplitudes increased. While the objective measure of postural sway increased with the increasing combination of elevation and inclination, the subjective measure of stability did not show a significant two way interaction, implying that the participants were not able to perceive the combined risk to postural imbalance, causing potential inability to deploy appropriate postural muscle corrective actions.
Kinematic contribution and synchronization of the trunk, hip, and knee during free-dynamic lifting
Authors: Davis Kermit G. , Splittstoesser Riley E. , Marras William S.
Published: May 2021

Although there have been numerous studies evaluating the difference between stooped and squat lifting styles, there remains a lack of understanding of whole body kinematics during unrestricted lifting. The current study evaluated nine males and nine females while lifting two box weights (9.1 kg, 18.2 kg) from five origins below the waist (0, 19, 38, 57, and 76 cm above the floor) and from three task asymmetries (sagittally symmetric, 45° clockwise, 45° counter-clockwise). While the lifting style was significantly influenced by the height of lift origin and to a lesser extent gender, box weight, and task asymmetry, none of the conditions resulted in pure squat or stoop lifting style. However, for lifts above knee height, the lifting style resembled more of a stoop lift while lifts originating below knee height were more of a squat lift. As the origin moved closer to the floor, participants relied more on their hips to accomplish the sagittal flexion but overall adopted a more coordinated whole-body lifting style. All together, as more sagittal flexion is required, more joints are relied upon in a more coordinated effort. The current study indicates that caution needs to be exercised when applying results of pure squat or pure stoop lifting studies to free-style (realistic) lifting.
Effects of job instruction on maintenance task performance
Authors: Chervak Steven G. , Drury Colin G.
Published: May 2021

Written documentation has been implemented in aviation maintenance errors so that documentation becomes an important safety issue. A restricted technical language for job instruction, Simplified English was tested to determine whether or not it reduced error rate in a maintenance task. Experienced and inexperienced participants performed on easy and a difficult maintenance task on a small internal combustion engine using three languages of job instruction: original, Simplified English and a hybrid. Task errors were reduced with Simplified English but increased with the hybrid version. While the easy task and the experienced participants made fewer errors, neither participant expertise nor task difficulty interacted with instruction language. Hence, Simplified English can be recommended, but hybrid instructions should be avoided.
Simulation for sagittal plane lifting activities
Authors: Ayoub M.M.
Published: May 2021

Biomechanics provide estimation of various mechanical stresses acting on the body while a person manually handles an object. Although motion analysis systems are available for dynamic biomechanical analyses, uses of such systems are mostly performed in laboratory due to high cost of the equipment and the expertise required in using them. Industrial ergonomists have limited access to dynamic biomechanical analyses. This paper reports a dynamic simulation model developed for biomechanical analyses of sagittal lifting activities. The model simulates the dynamic motion of lifting tasks for five body joints: the elbow, shoulder, hip, knee, and ankle. The inputs of the model include initial and final joint postures; gender, weight, and height; weight of load; lifting height; and container dimensions. The output provides the angular trajectories of the five joints. The model without any video inputs predicts the motion patterns of the lift. Actual motion data were collected using 10 subjects in the laboratory for 360 lifts which included 12 lifting tasks in combination of two lifting heights, two container sizes, and three weights of load. Good results were obtained from the dynamic planar motion simulation model. The predicted motion patterns from the simulation closely resemble the observed motion pattern.
The effect of workload, work experience and inclined standing surface on visual spatial perception: Fall potential/prevention implications
Authors: Kincl Laurel , Bhattacharya Amit , Succop Paul , Bagchee Angshuman
Published: May 2021

Maintenance of upright balance involves interplay between sensory (somatosensory, vestibular and visual) inputs and neuro-motor outputs. Visual spatial perception (VSP) of vertical and horizontal orientation plays a significant role in the maintenance of upright balance. For this experiment, a custom designed computer program randomly generated 42 images of horizontal and vertical lines at various angles for 60 industrial workers (39 ± 9.8 years). Half of the workers had more than three years of experience working on inclined and/or elevated surfaces. The main effects investigated included within subject factors of standing surface inclination (0°, 14° and 26°), job experience (number of months), and postural workload (0%, 50% or 100%). The VSP outcome measure was the count of correct responses to the angles presented. The inclination did not have a significant effect on VSP, but the parameter estimates indicated less correct responses on the inclined surfaces. The postural workload significantly affected the VSP, indicating that with increased workload, less correct responses were given. Finally, job experience was found to improve VSP response scores. In summary, these results indicate that job experience increases accurate VSP, while workloads and inclined work surfaces decrease accurate VSP responses.
Gait adaptations during load carrying on level and inclined surfaces
Authors: Cham Rakié , Redfern Mark S.
Published: May 2021

The complex human processes involved in balance maintenance and fall prevention during normal locomotion are further complicated by load carrying and/or the presence of slippery floors. The goal of this study was to investigate the effect of carrying loads (2-handed method) on gait biomechanics relevant to slips/falls. Participants walked down surfaces of varying inclinations (0°, 5° and 10°), while ground reaction forces and body/foot motion were recorded. Three load conditions (no load, 2.3 and 6.8 kg) were included. Load carrying was associated with increases in the peak normal ground reaction force and in the rate of the normal loading phase on the leading foot. Shear ground reaction forces were not affected by load carrying. Changes in the ground reaction forces recorded during load carrying led to reduced required coefficient of friction (RCOF) values, a variable used to rate slip potential. This RCOF reduction is partly due to postural adaptations such as increased knee and hip flexion adopted during load carrying. Furthermore, load carrying was accompanied by slower heel contact heel velocity in the direction of motion. Finally, moments generated at the hip and knee joints were significantly biased towards the extensor and flexor direction, respectively.
Estimation of load transfer force to the hands during sagittal plane box lifting
Authors: Eger Tammy R. , Stevenson Joan M.
Published: May 2021

Load transfer force to the hands was investigated to provide an accurate estimate of load transfer during sagittal lifting tasks for application in an industrial setting. The effects of gender, load mass, lift style, load transfer duration and participant strength were examined as possible variables to improve the estimation of load transfer force. Ten healthy men and eleven healthy women completed a total of 25 box lifts using a freestyle technique. Kinematic data were collected using the OPTOTRAK™ and a portable video camera. Measured load transfer force (MLTF) was determined as the total load weight minus measured values from a force plate. Five methods of estimating load transfer to the hands were calculated and compared with MLTF. The enhanced load transfer force method (ELTF) of estimating load transfer to the hands was superior to all other estimation methods.
Inspectors' performance and understanding in sheet steel inspection
Authors: Dalton Jean , Drury Colin G.
Published: May 2021

Three studies were performed to better understand the complex task of sheet steel inspection for multiple surface defects. Their aim was to combine techniques from off-line performance measurement studies with interviews and questionnaires coming from a more holistic tradition of inspection. In this way, more detailed insights were obtained from three studies of nine highly-trained and experienced steel inspectors. The performance study was designed to compare lighting conditions using a visual search task. It did not find lighting differences, but did find other task differences and the typical large individual differences. These individual differences were explored further with detailed interviews, a task analysis and a detailed questionnaire. Areas of significant agreement among inspectors were found, as were responses that differentiated high from low performing inspectors. Rasmussen's skill/ rule/ knowledge classification was used to aid the analysis of these latter studies, showing the contribution of higher-level cognitive processes to the inspection task.
Muscle strain associated with operating three models of fire nozzles and subjective assessment of their ergonomic quality
Authors: Kluth Karsten , Pauly Olaf , Keller Erwin , Strasser Helmut
Published: May 2021

Firefighters are subject to high physical and psychological stress and fire fighting often requires mastering complicated tasks under adverse conditions. In this job, the handling of the hose/nozzle combination is a central and often performed task. The objective of this field study was to ergonomically evaluate different designs of 3 fire nozzles – a multi-purpose nozzle according to a German standard, a pistol nozzle (AWG), and a supposedly ergonomic nozzle (Quadrafog) – with respect to the muscle strain associated with performing standardized working tests. Eleven firefighters (10 males and 1 female, aged 27–54) used the 3 nozzles in the practice area of a fire station. For 3 different working tasks (straight stream, wide fog, and alternating operation), electromyographic activity was monitored continuously from 7 muscles of the right and left hand-arm-shoulder system using a PC-based mobile data registration system. Specially developed questionnaires provided subjective assessments of the ergonomic quality of the fire nozzles. The standard nozzle – which is still very frequently used – is only suited for "water go" for extended periods of time, but not for dynamic work. Especially the nozzle operator's arm musculature is subjected to high strain by the hose forces, which depend on water pressure and flow. AWG and Quadrafog led to substantially lower overall strain and smaller static components. Only in pure straight stream fire fighting was there no difference between the standard nozzle and the other models. High static portions characterize straight stream as well as wide fog operation. Both operations required small movements of the body so that the static portions became more noticeable. Overall, the AWG fire nozzle exhibited the most balanced strain profile with non-critical static values and a tolerable overall strain for alternating operations. These results are in accordance with the fire fighters' subjective preference for this model. It is unfortunate that currently the sole focus remains still on the price rather than the usability, which determines the physiological costs that must be paid by the operator. In the future, more attention should be paid to the compatibility between the characteristics of the human organism and the technical components of the tool.
Assessment of the ergonomic quality of file handles using electromyographic and subjective methods
Authors: Kluth Karsten , Kellermann Horst G. , Strasser Helmut
Published: May 2021

In a comparative investigation 3 file handles were evaluated with regard to their ergonomic quality. By means of a mobile measuring system for the recording of peripheral-physiological data, the muscle strain of 9 muscles of the left and right hand-arm-shoulder system was quantified with surface electromyography. A special laboratory device facilitated the standardized execution of the tests. A specific bipolar questionnaire had enabled the subjective assessment of the design, surface material, general usability, avoidance of pressure marks and blisters, suitability for the exertion of the necessary pressure and pushing forces, and the suitability during hand perspiration. Also, the assessment of more or less favorable body positions to various filing directions was made. From substantial differences in the objective data and the subjective evaluation, the inference has to be drawn that only the combination of subjective surveys and objective measurements represent the opportunity to assess the ergonomic quality of working tools adequately.
Differences in muscular activation and fatigue for intermittent and constant load
Authors: Roman-Liu Danuta , Kȩdzior Krzysztof
Published: May 2021

The aim of this study was to compare the influence of constant or intermittent load on muscle activation and fatigue. The analysis and assessment of muscular activation and fatigue was based on surface EMG measurements from eight muscles (seven muscles of the right upper limb and trapezius muscle). Two EMG signal parameters were analyzed for each of the experimental conditions distinguished by the value of the external force and the character of the load – constant or intermittent. The amplitude related to its maximum (AMP) and the slope of the regression line between time and median frequency (SMF) were the EMG parameters that were analyzed. The results showed that constant load caused higher muscular fatigue than intermittent load despite the lower value of the external force and lower muscle activation. Results suggest that additional external force might influence muscle activation and fatigue more than upper limb posture. The results of the study support the thesis that all biomechanical factors which influence upper limb load and fatigue (upper limb posture, external force and time sequences) should be considered when work stands and work processes are designed. They also indicate that constant load should be especially avoided.
Occupational chronic neck and shoulder pain: Study conducted in Sweden
Authors: Fredriksson Kerstin , Bildt Carina , Toomingas Allan , Alfredsson Lars
Published: May 2021

In 1969 a population-based study was conducted in Stockholm. From the 2579 randomly selected participants (age 18–65 in 1969), the youngest subsets were asked to participate in a re-examination in 1993. In 1997 a second follow-up was performed. The aim of the present study was to identify work- and leisure-time-related conditions that contribute to the development of chronic neck/shoulder pain. Variables regarding both physical, psychosocial and lifestyle conditions from the 1993 re-examination were included in the analyses. Women were more likely to developed chronic neck/shoulder pain than men. Among women, poor coping strategies, lack of social support, time pressure at work and work with hands above shoulder level were found to be associated with chronic neck/shoulder pain. No associations were found among men. Signs at a medical examination could only predict chronic pain to a minor extent. The results from this study shows that both work- and leisure-time-related conditions contribute to the development of chronic neck/shoulder pain among middle aged women.
Structural anthropometric measurement of Atlantic offshore workers
Authors: Reilly Tara , Kozey John , Brooks Chris
Published: May 2021

This study provides information on structural dimensions of offshore workers with and without a helicopter passenger suit. Forty-one structural measures, with and without a helicopter passenger suit, were obtained from 42 subjects (38 M, 4 F). The structural dimensions of the subjects demonstrate an increase with suit, circumferences increased by as much as 246 mm, vertical measures (stature) increased by 14 mm to 41 mm, and horizontal measures (breaths) increased by 15 mm to 37 mm. The difference (suit vs. no suit) in waist circumference is less for a larger subject compared to a smaller subject indicating suit sizes need further consideration.
Maximum one-handed shoulder strength for overhead work as a function of shoulder posture in females
Authors: Garg Arun , Hegmann Kurt T. , Kapellusch Jay
Published: May 2021

A laboratory study was conducted to determine the maximum voluntary strength (MVC) and maximum voluntary torque for one-handed lift and hold and hold only tasks as a function of shoulder posture. Twelve female volunteers of 21–33 years of age, claimed to be in good physical health and stated they had never had any musculoskeletal or cardiovascular problems participated in the study. One-handed maximum voluntary strength was defined as the maximum weight that a subject could lift and hold for 4 seconds (lift and hold) or hold the weight for 4 seconds without lifting from table height (hold only). MVC was measured in six different postures most commonly used in automobile assembly: 0/90 (shoulder flexion angle=0° and included elbow angle=90°), 30/90, 60/90, 90/120, 120/150, and 150/180. An analysis of variance showed that hold only MVCs were significantly higher than lift and hold MVCs by an average of 26%. Shoulder posture had significant effect on both types of MVCs. The strongest posture was 0/90 and the weakest posture was 90/120. There was large variability between subjects and some subjects had maximum shoulder strength as low as 4.3 kg. The findings of this study indicate that female have very low shoulder strength especially for jobs requiring overhead work.
Effect of the reach distance on the execution of one-handed submaximal pull forces
Authors: MacKinnon Scott N. , Vaughan Christopher L.
Published: May 2021

This study examined the effects of reach distance on the lumbar spine kinematics and electromyographical activities (EMG) of eight selected muscles of the trunk and shoulder during submaximal horizontal pulling exertions (12% of lean body mass) all located at elbow height. Eleven healthy male volunteer subjects were asked to pull on a load located at varying distances (10, 15, 20, 25, 30, 35 and 40% of subject stature) from the frontal plane containing the load handle. Trunk kinematics in the sagittal plane, as monitored by a Lumbar Motion Monitor, increased significantly as reach distance increased. EMG data revealed increasing erector spinae activity as reach distance increased and this muscle group was found to be co-active with external oblique muscles during the exertion. Shoulder complex muscles were found to be highly active in all conditions, but only the trapezius and deltoid demonstrated significantly decreasing activity as pull reach increased. These data provide some direction in positioning the operator within a workstation demanding pull force exertions.
Ergonomic evaluation of screwdriver handles under different working conditions
Authors: Ozalp Turker , Babalik Fatih C.
Published: May 2021

Maximum torque strength, muscle strain and subjective responses were evaluated in a series of screwdriver tests with 10 varied handles, performed under different working conditions. Screwing in and unscrewing tasks that affected inward and outward rotations of the upper extremity muscles were measured. Maximum torque strength for supination and pronation was determined under the conditions of dry hands, using industrial gloves, and with oily hands, consecutively. Physiological cost of performance was simultaneously determined by measuring electromyographic activities (EA) of 5 muscles of the hand-arm-shoulder system that were expected to be involved in screwing tasks. Subjective assessments were made through a questionnaire before and after each experiment. Significant differences were determined between maximum torque values produced during inward and outward rotations for the three operational cases. Maximum torque values exerted by the twelve subjects using industrial gloves were substantially higher than the values obtained by dry and oily hands during both supination and pronation. EA values of the 5 muscles investigated differed significantly. However the subjective assessments of the handles did not vary in the pre and post assessments.
A model of the relations between risk perception and self-reported safety activity
Authors: Stave Christina , Pousette Anders , Törner Marianne
Published: May 2021

A hypothetical model based on theories on stress, coping and motivation, describing the associations between risk perception and self reported safety activity, was tested. Structural Equation Modeling (SEM) was used for the analysis of data from a cross-sectional questionnaire survey of 315 randomly selected Swedish farmers and farm workers. The results lent support for a model where the effects of risk perception on safety activity were mediated by two parallel paths, job stress and risk manageability. These two mediating mechanisms balanced each other out so that no direct influence of risk perception on safety activity was found. The results therefore suggest that, to increase and prioritize safety activity, efforts should be made to increase perceived risk manageability, supporting safety solutions simultaneously with efforts to reduce felt stress. Interventions focusing solely on risk perception, such as giving information about the negative consequences of risks, may result in little positive effect on safety activity.
The influence of feedback and shifts in the probability of faulty objects on quality inspection
Authors: Schütte Martin
Published: May 2021

The aim of the present investigation was to prove in which way the decisions of quality inspectors are influenced by a change in the probability of faulty products, the kind and regularity of feedback. 72 participants took part in the experiment. The proportion of faulty objects was manipulated in three ways. The rate of a faulty object constantly amounted to 14% or increased from 11 to 17% or decreased from 17 to 11%. During task execution there was either no feedback or information about the number of missed faulty objects or about the number of missed faulty objects as well as the number of false alarms. Feedback was given either constantly after inspection of 20 objects or after a varying number of objects which however amounted to 20 on average. The so-called c-index was calculated describing the response bias. The experimental results demonstrate that the decision behavior is changing in dependence on shifts of the number of faulty objects when feedback takes place at irregular intervals and when the number of missed faulty objects is given as feedback. The results are discussed with respect to possible work design measures adequate for the stabilization of the decision behavior.
Ergonomic demands in automotive component inspection tasks
Authors: Landau Kurt , Peters Helmut
Published: May 2021

Investigations revealed poor ergonomic design, unsatisfactory logistics and quality problems at assembly and inspection workplaces in a large corporation supplying fenders to the automotive industry. A 138-item job design checklist was used to assess 59 reference workplaces. The design profiles highlighted weak points, especially as regards anthropometry and movement sequences. Ergonomically optimised assembly and inspection workplaces compatible with production flow were designed and introduced. Productivity improvement groups were created and action was taken to encourage good ergonomic behaviour. Job contents were enlarged.
Stress screening procedure for the automotive industry: Development and application of screening procedures in assembly and quality control
Authors: Winter Gabriele , Schaub Karlheinz , Landau Kurt
Published: May 2021

Assembly work and inspection and testing tasks tend to be combined nowadays in the automotive industry as a way of achieving job enrichment. Workers inspect and test parts manufactured or assembled by them. This is in addition to routine quality assurance activities. As well as introducing new sensory demands into the jobs, this integration of assembly and inspection activities also brings with it significant additional motor components, which lead to musculo-skeletal strains. No empirical studies of the superimposed stresses involved in this type of job has been performed to date in the automotive industry. A ergonomically representative sample of work at 22 work stations shows that, whilst most of the work is performed close to the body and involves a substantial proportion of standing positions and strenuous forced postures, only relatively low levels of forces have to be applied. In contrast, tasks requiring the use of testing tools have to be performed farther from the body and higher forces have to be applied. The findings reported from this study led to the design of a screening procedure for the predominantly physical stresses arising in assembly and inspection work in the automotive industry.
Integration of inspection tasks into machine operators' jobs in the consumer goods industry
Authors: Landau Kurt , Wiese Gero , Bopp Verena , Sinn-Behrendt Andrea , Winter Gabriele , Salmanzadeh Hamed
Published: May 2021

Because workers operating machines under mass production conditions frequently have extremely narrow, highly repetitive job contents which result in unilateral strains, a company manufacturing goods for the consumer industry sought to achieve job enrichment in this type of activity by introducing three different inspection tasks to supplement machine operation. A study of 12 workplaces using the Key Features Method, plus the IAD-BKA, OCRA- and RULA procedures and an energy expenditure calculation demonstrated the stress-reducing effect of the job enrichment concept. The EMG analyses performed on four selected muscles over a total of 12 full-shift working days also support the assumption that changes in types of stress will be beneficial. In contrast, the before/after-shift results obtained with the Nitsch Self-rating Scale and the NASA Task Load Index indicated increases in perceived strains and decline in motivation in all subjects – despite the job enrichment action. For this reason further ergonomic job redesign action is proposed.
Risk for DVT for airline passengers and flying personnel
Authors: Sudoł-Szopińska Iwona , Błachowiak Krzysztof , Koziński Piotr
Published: May 2021

Civil aviation passengers, including growing number of people traveling on business, as well as airline crew members are the groups of occupational risk, and have been discussed for years in the context of deep venous thrombosis (DVT). DVT is one of the most common problems faced by the clinicians in medicine today. Not only is there difficulty in making a definitive diagnosis but also in initiating proper treatment, especially as DVT is often asymptomatic and goes undiagnosed with potentially fatal consequences. The main risk factor of DVT is venous stasis caused by a prolonged sitting posture in cramped economy class aircraft seats, hence the name of the medical condition: economy class syndrome. A specific microclimate of the airplane which is characterized by changes in air temperature, mild hipoxia and very low humidity also plays a significant role. Notwithstanding the growing popularity of the airplane as the means of transportation, the linkage of DVT and pulmonary embolism with airline travels remains unexplained. This paper presents a review of findings from the studies devoted to the aforementioned issue together with the examination of risk factors of DVT, DVT diagnostic methods and proposed guidelines for the prevention of DVT during airline travels which should include, amongst others, regular exercises, walking, drinking water and the use of preventive measures, such as: compression stockings and medications.
Work-related chronic venous disease in office and bakery workers
Authors: Sudoł-Szopińska Iwona , Panorska Anna Katarzyna , Koziński Piotr , Błachowiak Krzysztof
Published: May 2021

A prospective study was undertaken in order to establish the prevalence and risk factors of chronic venous disease (CVD) in two occupational groups: office employees working in a prolonged sitting or standing position, and people working in bakeries, in a hot microclimate. It included 160 individuals over 40 years old, 97 women and 63 men. A survey assessing subjects' work place ergonomics, Doppler sonography – currently the diagnostic tool of choice in the assessment of sufficiency of venous valves, and an observational study were performed. Doppler signs of CVD in persons working in sitting or standing positions and in hot microclimate were found in 59.4%, 83.4% and in 76.4%, respectively. Most often diagnosed were perforating veins and vena saphena magna incompetence. Occurrence of CVD was significantly higher in people working in a standing position than in those working in a sitting position (p-value =0.0145). Occurrence of CVD among office workers working in sitting or static standing conditions and among people working in a hot microclimate were comparable (p-values =0.1152 and 0.7116, respectively). Conclusions: Occupational CVD is a frequent condition among office workers and people working in a hot microclimate. Static standing position at work constitutes a significantly greater risk for CVD development than prolonged sitting or work in a hot microclimate and thus should be a subject for specific prophylaxis interventions.
Hydraulic-actuation joystick use: A torque, range of motion and electromyographic description
Authors: Murphy Taylor A. , Oliver Michele L.
Published: May 2021

The purpose of this work was to quantify upper limb and joystick kinematics, muscle activation of the prime movers and stabilizers of the shoulder (anterior deltoid, posterior deltoid and upper trapezius) as well as torque exerted by operators of hydraulic-actuation joystick controllers. Dynamic and impact torques were captured through the use of an instrumented joystick. Results indicate that the impact torque (5.36 ± 1.75 N·m for forward motion) sustained as the joystick reaches the end range of motion is substantial and is more than twice that of the operator exerted torque prior to reaching the hard endpoint. EMG data confirm that the upper trapezius is in a state of constant but low level activation, which may be largely attributable to postural demands forced upon the operator by the armrest.