A randomized intervention trial to reduce mechanical exposures in the Colombian flower industry

Evidence on the effectiveness of ergonomic interventions to reduce mechanical demands and upper-extremity MSDs is scarce in agriculture. We conducted an intervention to reduce mechanical exposures during manual flower cutting through job rotation, education and reduction of force requirements. One-hundred and twenty workers (20 to 60 years old; 89% women) from six companies that cultivate roses participated in this study. Three companies were randomly assigned to control and intervention groups. We studied changes between baseline and follow-up in self-reported effort and upper-extremity postures, kinematics and muscular activity. Most of the observed changes were moderate for both groups. The intervention group showed differential improvements compared to the control group for the maximum wrist radial deviation and forearm pronation, and acceleration of the forearm supination-pronation and elbow flexion-extension; and the muscular activity of the flexor and extensor carpi radialis and the flexor carpi ulnaris. However, we also observed that the maximum ulnar deviation, velocity of the wrist flexion-extension and muscular activity of the extensor carpi ulnaris improved more in the control group. These mixed results may be related to limited time for intervention adjustment, and uncontrolled task changes in the control group. Future research should address these issues and test other solutions.     

Ergonomic evaluation of laparoendoscopic single-site surgery ports in a validated laparoscopic training model

Although laparoendoscopic single-site surgery (LESS) is feasible among expert laparoscopic surgeons, it poses many technical challenges not seen in conventional laparoscopy (CL). Recent technological advancements in single-incision instrumentation have created more interest and widespread usage of LESS. However, neither LESS nor its novel instrumentation have been thoroughly studied or evaluated using human factors and ergonomics techniques. Consequently, the aim of this study was to compare the physical performance of LESS to CL using a standardized task. Wrist and elbow angular movements, range of motion and physical discomfort were assessed for 24 novice participants. There were no significant differences for physical comfort/discomfort ratings or elbow and wrist flexion/extension range of motion between CL and LESS. However, wrist radial/ulnar range of motion was significantly greater in LESS compared to CL (p < 0.05). Additionally, wrist radial/ ulnar range of motion was significantly greater using the SILS Port compared to the GelPOINT (p < 0.05). Although further investigation is needed, LESS resulted in greater wrist deviation and range of motion due to the close proximity of the instruments, restrictive nature of the single-port devices, and the need to achieve adequate instrument triangulation and visualization.     

Ergonomic evaluation in a values transportation company in Venezuela

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

The study of wrist postures of musicians using the WristSystem (Greenleaf Medical System)

This study examined wrist motions of instrumentalists who have never experienced a cumulative traumatic disorder. Eighteen student musicians ranging from 18 to 29 years of age, with more than 9 years of playing experience participated in this study using the WristSystem (Greenleaf Medical System). The wrist motions were measured while participants played their instrument for five minutes. The results indicated a different pattern of wrist movements for each instrumentalist. Pianists demonstrated more ulnar deviation for both hands and more flexion for the left hand than any of the other instrumentalists. The average wrist range of motion for all four movements was under 15 degrees for violinists and violists. The right hand of the cellist had more flexion than any other instrumentalists. For both hands, flutists had more wrist extension than any other instrumentalists. This study provided information about wrist motions of musicians as one of the many factors that contribute to cumulative traumatic disorders. However, further research is needed to identify causal factors, and to promote prevention of the injury.     

Assessment of physical exposures and comparison of exposure definitions in a repetitive sawmill occupation: trim-saw operator

This paper describes the physical exposures required to perform a sawmill job associated with a high incidence of upper extremity musculoskeletal injury. Exposure variables are described by multiple posture, exertion and frequency definitions and the comparability of those definitions are examined. Effective industrial prevention efforts require an accurate assessment of risk. Surface electromyography and electrogoniometry were used to quantify the physical exposures of 29 trim-saw operators in four sawmill facilities. Average wrist ranges of motion of 32, 57 and 58 degrees in wrist radial/ulnar deviation, flexion/extension and pronation/supination respectively were required to perform the job. Defining wrist range of motion by the peak postures observed versus those required to perform the primary task resulted in significantly different ranges of motion (p<0.05). Job performance required an average of 33% of maximum voluntary contraction. Repetitions per day ranged from 3,549 to 14,460. Percentage of maximum voluntary contraction was not associated with psychophysical measures of exertion.     

Are cutout handles used when available in real occupational settings? Description of grips and upper extremities movements during industrial box handling

In order to achieve better postures and decrease musculoskeletal risks adequate design of hand/box couplings for manual materials handling (MMH) are still needed. No studies evaluating upper limb movement thorough direct measurements during box handling in workplace were identified in the literature. In this study we describe the types of grip and movements adopted by ten workers when handling redesigned boxes with cutout handles between different heights on industrial pallets. The new handles were used by 90% of the workers through different types of grip. Electrogoniometric measurements showed relatively safe forearm and wrist movements, although elbow inadequate range of movement was recorded. Despite the good acceptance of the cutout by workers, the new design requires extra internal space in the boxes reducing applications for this alternative of box.     

Comparison of five approaches to keeping power line maintainers' hands warm during work in the cold

Electric utility workers in Canada must frequently work in the cold and must wear thick rubber gloves which can result in rapid fatigue and reduced performance. The purpose of the study was therefore to document the challenge of working in the cold wearing the standard five-finger rubber gloves and covers and compare them to two equipment options, mitten style gloves or a prototype wool liner, and two heating options, glove or torso heating. The dependent measures were grip force, temperature, dexterity (modified Purdue pegboard test and a simulated occupational task), finger sensitivity (Von Frey hair test), perceived effort and thermal sensation. The study population consisted of 10 experienced male utility workers. They worked in a controlled temperature walk-in chamber (-20 degrees Celsius) and performed simulated utility work for 45 minutes with interspersed test batteries. The mitten style glove and woolen liner in a standard glove reduced the effects of working in the cold compared to the standard five-fingered variety with a thin cotton liner. We found that the mitten style glove showed lesser drops in skin temperature for the 3rd and 5th digits than the other conditions (p < 0.05).     

Distal upper extremity musculoskeletal risk factors associated with colonoscopy

Gastroenterologists are at increased risk for developing recurrent thumb, hand, and elbow pain due to colonoscopy procedures. We evaluated forearm muscle loads and wrist postures during routine colonoscopy (N=12 gastroenterologists) to understand distal upper extremity musculoskeletal risk factors associated with the 4 different subtasks of colonoscopy. Bilateral forearm extensor carpiradialis (ECR) and flexor digitorum superficialis (FDS) surface electromyography and bilateral wrist postures were recorded continuously. The mean duration of colonoscopy was 24.2 (± 12.1) minutes and was dominated by the withdrawal subtask [13.7 (± 8.8) min] followed by right colon insertion [5.8 (± 4.8) min], left colon insertion [3.5 (± 3.1) min], and retroflexion [1.2 (± 2.1) min]. Median (APDF50) and peak (APDF90) left forearm muscle activity was significantly greater than right forearm muscle activity across all subtasks. Median and peak ECR muscle activity was significantly greater during the left and right colon insertion subtasks compared to retroflexion. Both wrists were predominantly in wrist extension during all phases of colonoscopy. The left forearm muscle activity was higher than right forearm activity due to differences in wrist posture and grip force. The risk factors for the left hand may be reduced with alternative designs and support mechanisms for the colonoscope head.     

Factors contributing to work related low back pain among personal care workers in old age

This study aims to preliminary explore the work related and individual factors that contributed to the occurrence of low back pain (LBP) that affected work activities of Personal Care Workers (PCWs). A cross-sectional study was conducted to 36 PCWs in an old age home of Hong Kong. The study is divided into three parts: 1) a questionnaire to document the workload exposure factors and the musculoskeletal symptoms survey of the PCWs, 2) work posture evaluation; and 3) an evaluation of the physical fitness and lifting capacity of the PCWs. Univariate analyses were used to explore the risk factors associated with LBP that affected work activities. The results indicated that individual physical profile and lifting capacities did not contribute to occurrence of low back pain at work. For the work demand factors, the perceived physical demands in lifting and lowering heavy objects, awkward sustain neck and back postures, loading on the back, and perceived effort of cleaning task contributed to the occurrence of LBP. For the physical environment factors, thermal stress and improper ventilation were associated with the occurrence of LBP cases. For the individual factor, LBP cases were associated with workers' self perceived muscular effort, and perceived risk of mental illness in response to work requirements.     

Ergonomics in the operating room

Surgical staff is considered to have several ergonomic risk factors, but their physical workload and musculoskeletal health have seldom been evaluated. Clinical examinations of neck and upper extremities were performed in 99 theatre nurses and 93 assisting nurses, all females. Their physical workload was assessed by questionnaire, and by technical measurements of postures, movements and muscular load in subgroups of both categories. The prevalences of diagnoses in neck/shoulders were not remarkably high in the nurses, compared to other occupational groups. In elbows/hands though, the prevalence was rather high among assistant nurses, 13 vs. 5 % in theatre nurses; POR 3.0 (CI 95 % 1.0 - 8.9). Theatre nurses experienced prolonged static postures in the questionnaire, whilst assistant nurses reported high physical load. Accordingly, the technical measurements showed more strenuous working postures in the theatre nurses, but lower wrist angular velocities. The time proportion of muscular rest in m.trapezius was rather high in both groups. Although both groups had some stressful loads they had relatively low prevalence of diagnoses in neck/shoulders. The high proportion of muscular rest may be protective. The elevated risk of elbows/hands diagnoses among assistant nurses may be explained by strenuous work tasks of short duration.     

Ergonomics of novices and experts during simulated endotracheal intubation

Endotracheal Intubation (ETI) is an airway procedure commonly used to secure the airway for a variety of medical conditions. Proficiency in ETI procedures requires significant clinical experience and insufficient data currently exists describing the physical ergonomics of successful direct laryngoscopy. The research objectives of this study were to examine how ETI time, error and practitioner biomechanics varied among clinical experience levels and hospital bed heights. The participant population included novice and expert personnel, differentiated by their exposure to ETI procedures. Participants used a standard laryngoscope and blade to perform ETI trials on an airway manikin trainer at predesigned hospital bed heights. Participants were evaluated based on ETI time and accuracy, as well as wrist postures and muscle utilization. Hospital bed height did not affect task completion time, error rates or muscle utilization. Expert participants exhibited less ulnar deviation and forearm supination during task trials, as well as a higher utilization of the bicep brachii and anterior deltoid muscles. Expert grasped instrumentation differently, requiring less wrist manipulation required to achieve ideal instrument positions. By encouraging ergonomic best-practices in hand and arm postures during ETI training, the opportunity exists to improve patient safety and reduce the learning curve associated with ETI procedures.     

Work-family conflict among IT specialty workers in the US

Specialty workers are a source of critical, locally scarce technical skills. This study aimed to understand the experience of work-family conflict among specialty workers in the US by exploring the process of transitioning from working in their home countries to working in the US. While participants perceived initial difficulties in adapting to the new environment, over time, they experienced lower work-family conflict in the US compared to working in their own home countries. In their home countries, where work and family domains were considered separate and culturally defined boundaries separating these domains are rigidly maintained; these participants relied heavily on family support to manage work-family conflict. Moving to the US, where greater integration of work and family domains is prevalent, these participants managed work-family conflict by revisiting altered demands, accessing alternate organizational resources and learning new skills to create and maintain work-family boundaries. This study contributes to the nascent body of literature on work-family relations in the context of international migration by highlighting a specific case of Indian specialty workers who adopt different boundary-spanning strategies to manage work-family conflict in changed social and working conditions. In essence, participants managed work-family conflict by using enhanced autonomy to increase flexible working and accessing other resources such as supervisory support and organizational flexible working policies.     

Biomechanical modelling and evaluation of construction jobs for performance improvement

Occupational risk factors, such as awkward posture, repetition, lack of rest, insufficient illumination and heavy workload related to construction-related MMH activities may cause musculoskeletal disorders and poor performance of the workers, ergonomic design of construction worksystems was a critical need for improving their health and safety wherein a dynamic biomechanical models were required to be empirically developed and tested at a construction site of Tata Steel, the largest steel making company of India in private sector. In this study, a comprehensive framework is proposed for biomechanical evaluation of shovelling and grinding under diverse work environments. The benefit of such an analysis lies in its usefulness in setting guidelines for designing such jobs with minimization of risks of musculoskeletal disorders (MSDs) and enhancing correct methods of carrying out the jobs leading to reduced fatigue and physical stress. Data based on direct observations and videography were collected for the shovellers and grinders over a number of workcycles. Compressive forces and moments for a number of segments and joints are computed with respect to joint flexion and extension. The results indicate that moments and compressive forces at L5/S1 link are significant for shovellers while moments at elbow and wrist are significant for grinders.     

Workload composition of the organic horticulture

This project aimed the characterization of the physical workload of the organic horticulture by determining the frequency of exposure of operators to some activity categories. To do this, an adaptation of the PATH method (Posture, Activities, Tools and Handling) was done to be used in the context of agriculture work. The approach included an evaluation of physical effort demanded to perform the tasks in the work systems from an systematic sampling of work situations from a synchronized monitoring of the heart rate; a characterization of posture repertoire adopted by workers by adapting the OWAS method; an identification of pain body areas using the Corlett diagram; and a subjective evaluation of perceived effort using the RPE Borg scale. The results of the individual assessments were cross correlated and explained from an observation of the work activity. Postural demands were more significant than cardiovascular demands for the studied tasks, and correlated positively with the expressions of bodily discomfort. It is expected that, besides the knowledge obtained of the physical effort demanded by organic horticulture, this project will be useful for the development of new technologies directed to minimize the difficulties of the human work and to raise the work productivity.     

Relationship between productivity, quality and musculoskeletal disorder risk among deboning workers in a Chilean salmon industry

The purpose of this ergonomic investigation is to establish a relationship between quality, productivity and risk of musculoskeletal disorder (MSD) in manual bone-removal process in the salmon fish industry. The method consists in a follow up study of 14 workers in a lane that processes salmon steak. Time between each steak (work cycle), quality of the steak's meat through inspection of deepness and length of the gapping generated by the manual bone-removal process and risk for musculoskeletal disorders through OCRA method were considered for this study. IMC and musculoskeletal Nordic Questionnaire of Kourinka were applied to the workers evaluated. Fourteen women worker's completed the evaluation, age 37.67 ± 8.1, with 65.27 ± 34.41 months of experience, with an IMC of 27.18 ± 3.87 (1.52 ± 0.057 meters of height) at the time of the evaluation. Time for deboning per steak averaged 38 ± 14 seconds with 68.33 ± 14.79 steaks per hour per worker. In quality terms, 74% of the steaks were qualified as "premium steaks" and 26% as "grade or industrial" (lower category and cheapest price). OCRA index for the right hand average 13.79 ± 4.59 and 3.59 ± 0.41 for the left hand. From Nordic questionnaire 80% of the workers manifested musculoskeletal symptoms in the right hand/wrist, followed up by shoulder with 60% of the workers and arm/elbow with over 50%. There was no statistically significant relationship between productivity and quality of the steak after manual bone removal process and between quality and MSD risk. However, there was a statistically significant relationship between productivity and MSD risk (p<0.05). Discussion around the results allows to see complementary results that did have strong correlation between MSD risk and the presence of lower grade salmon steaks and between areas that present musculoskeletal symptoms (MSS) and the intensity of the MSS (p<0.05). The results showed that further research is needed to validate these relationships, due to the increasing demands of health-care services from this productive sector, considering its importance for this region.     

Gesundheitsförderliche Arbeitsgestaltung als Ansatzpunkt für das Recruiting in der Zeitarbeit

Temporary work agencies are constantly seeking new personnel. However, the industry’s image as well as reports on unfavourable working conditions impede the recruitment of new temporary agency workers (TAW). In the present study semi-structured interviews were conducted with 11 TAW to identify work characteristics that are perceived as potentially stressful and motivating, respectively. The results of the interview study can yield valuable hints for the improvement of the quality of work and further support the recruitment of new TAW. The results show that the working conditions of TAW contain a multitude of demands – e.g., high levels of insecurity, flexibility requirements and experiences of social marginalization – but only few resources. Starting from these insights possible measures are discussed that are suitable to improve TAW’s working conditions and provide recruiters with valuable arguments for the recruitment of new staff.     

Physiological stress assessment of female workers at kitchen workstation

This paper explores the extent of the physiological stresses of female workers at kitchen workstation while performing the various activities. For this a survey of eighty homemakers and experiment on sixteen respondents having similar physical and physiological parameters was done. Five activities in which the respondents faced maximum problems were selected and were standardized. Physiological stresses including cardiovascular, muscular, and energy expenditure during these activities were then assessed. Study revealed that fatigue during the selected five activities i.e. cutting, grating, rolling, kneading, dish washing, was felt mainly at the wrist, fore arm, followed by discomfort in the shoulders, upper arm, lower back and neck. Energy expenditure for these activities ranged from 7.0 to10 kJ\min, total cardiac cost of work (TCCW) was between 200.81 to 364.30 beats, physiological cost of work (PCW) was 12.82 to 26.26 beats\min; maximum for grating and minimum for rolling. The percent increase in heart rate was maximum for grating 38.56 and minimum for rolling 16.20. Reduction in grip and pinch strength of right hand was found more as compared to the left hand.     

Investigating the effects of physical and cognitive demands on the quality of performance under different pacing levels

The study was undertaken to investigate the effects of pacing on aspects of performance at an assembly task and on the operators' responses related to work behaviour, perceived workload and perceived stress. A particular objective of the study was to investigate whether physical and cognitive demands may interact in their influences on these effects. An assembly task was simulated in the laboratory and the level of pacing imposed, work height and memory load within the task were all varied. The results showed that the type of pacing commonly imposed (as is common with a lean manufacturing Takt time system in industry) can significantly affect both performance and perceived workload and stress. Physical demands (through work height affecting posture) and mental demand (through memory load) were also found to have significant effects, as would be expected from the many studies of these in the literature. More importantly, some interactions were found between pacing and work height in their effects on quality of assembly and the operator's own rating of performance, and between work height and memory load in their effects on errors. These findings will need to be taken into account by companies when implementing Takt time systems.     

Workers’ participation in wage setting: A gift-exchange experiment

This study analyzes the consequences of workers’ participation in the wage setting process on effort exertion. The experimental design is based on a modified gift-exchange game with firms specifying contract alternatives and workers deciding about the finally implemented alternative. The experimental data reveals that workers with participation rights are more sensitive to differences in wage offers: Low wage offers trigger negative reciprocity which dominates the positive incentive effects from high wage offers. On average, participation in the wage setting process leads to a decline in effort exertion.     

Professional collaboration in services for mentally handicapped people

There has been growing academic and practitioner interest in the problems of and opportunities for joint working in the care of mentally handicapped people. The paper outlines alternative methods of such joint working and tests these against survey and case study evidence. Attention is drawn to the danger that joint working may have little impact at patient level and the paper recommends an emphasis on the appointment of frontline key workers.