Lean job design and musculoskeletal disorder risk: A two plant comparison

This study examined the relationship between lean job design and work-related musculoskeletal disorder (WMSD) risk factors. Repetition, force, and posture were assessed for a sample of 56 production jobs across departments at a lean automobile-manufacturing plant and compared to 56 similar jobs at a traditional automobile-manufacturing plant. The results showed greater productivity in the lean plant: less waiting ( p = .006) and walking ( p < .001); and greater repetition exposure ( p = .001). The mean rating for repetition was 5.5 in the lean plant, compared to 5.0 in the traditional plant based on the Latko (1997) hand activity level scale. However, the lean plant had significantly lower peak hand force ratings ( p = .01). When examining force and repetition combined, the lean plant had a lower percentage of jobs above the American Conference for Governmental Industrial Hygienists (ACGIH)-recommended Threshold Limit Value (TLV ® ). The findings suggest that lean manufacturing does not necessarily increase workers' risk for WMSD injuries. © 2009 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63064/1/20159_ftp.pd

A case study of an ergonomic evaluation for a shop floor facility

The aim of this paper is to discuss and recommend solutions for the ergonomic hazards present in a shop floor type of manufacturing facility. This type of study is important since the ergonomic issues that concern the shop floor worker are different than those faced by the assembly line worker. The shop floor employee for the most part enjoys work satisfaction, task variety, and is able to control his own work pace. From an ergonomic standpoint, this is the preferred work environment. The focus of this paper is a case study. This study is a one-day ergonomic assessment of a plastic manufacturing facility located in New Jersey. The ergonomic hazards found in this facility provided valuable information for developing guidelines that can be applied in most shop floor facilities. Among these guidelines is the implementation of a program that includes joint participation from management and workers for hazard evaluation

Postoffer Pre-Placement Screening for Carpal Tunnel Syndrome in Newly Hired Manufacturing Workers

OBJECTIVE: We determined the predictive validity of a post-offer pre-placement (POPP) screen using nerve conduction velocity studies (NCV) to identify future cases of carpal tunnel syndrome (CTS). METHODS: A cohort of 1648 newly hired manufacturing production workers underwent baseline NCS, and were followed for 5 years. RESULTS: There was no association between abnormal POPP NCV results and incident CTS. Varying NCV diagnostic cut-offs did not improve predictive validity. Workers in jobs with high hand/wrist exposure showed greater risk of CTS than those in low exposed jobs (Relative Risk 2.82; 95% CI 1.52, 5.22). CONCLUSIONS: POPP screening seems ineffective as a preventive strategy for CTS

Development, application, and reliability of methods for ergonomic workload assessments in production evaluation and workstation design

Ergonomics assessments of conditions for humans at workstations and in manufacturing processes are necessary to prevent work-related musculoskeletal disorders and enhance efficiency and quality. Many methods can be used for this from systematic observations to direct measurements and simulation. Investigations of the accuracy and reliability of many methods as well as comparisons between them have been performed, but there is still need for further work as well as development of new methods.The inter- and intra-rater reliability of the OCRA checklist was studied through eleven ergonomists’ risk-assessments of ten video-recorded work tasks on two occasions. The statistical analysis included several parameters of reliability of which Cohen\u27s linearly weighted kappa was the primary measure. The inter-rater agreement of the OCRA checklist was 39%, and the weighted kappa was 0.43; the intra-rater dittos were 45% and 0.52. This indicated that the OCRA checklist is a moderately reliable tool.A risk assessment approach for digital human modelling (DHM) was developed. The approach included a reference database of epidemiological relationships between directly measured exposure and related musculoskeletal disorders. For illustration, a case in manual assembly was simulated; exposures were calculated and compared to the reference data to indicate the risk of WMSDs. The application and detailed assessment would be helpful to prioritise among different design solutions.A 3D digital prototype laparoscopic robotic console was ergonomically evaluated using the DHM tool IMMA with 12 manikins representing anthropometries of the Swedish and US population. Work-ranges of the console and the manikins were calculated, compared and ergonomically assessed using the Swedish standards and a US checklist for computer work. The assessment criteria related to the adjustable ranges of the screen height, height of the armrest, adjustable range of the pedals were not fulfilled. The DHM tool IMMA provides the possibility for a pre-production assessment of static work tasks

The Productivity Consequences of Two Ergonomic Interventions

Pre- and post-intervention data on health outcomes, absenteeism, and productivity from a longitudinal, quasi-experimental design field study of office workers was used to evaluate the economic consequences of two ergonomic interventions. Researchers assigned individuals in the study to three groups: a group that received an ergonomically designed chair and office ergonomics training; a group that received office ergonomics training only; and a control group. The results show that while training alone has neither a statistically significant effect on health nor productivity, the chair-with-training intervention substantially reduced pain and improved productivity. Neither intervention affected sick leave hours.ergonomics, chair, pain, DeRango, Upjohn

A retrospective study on the effect of implementing an ergonomics program in an industrial setting

In this retrospective study, the safety record of an industrial equipment manufacturing facility is analyzed between two years (1999 and 2000) to determine the positive effect of an ergonomics program implementation. Ergonomics-related musculoskeletal disorders are the most prevalent type of illness reported in industry today. In 1998, MSDs affected nearly 1 million employees nationwide and cost an estimated $45-$55 billion per year in workers\u27 compensation. Due to these alarming statistics, many companies are moving toward implementing controls and programs in the workplace to reduce worker exposure to ergonomics hazards. The facility in this study implemented an ergonomics program in January of 2000 and as a result, noticed a significant reduction in ergonomics incidents that year as compared to the previous year. Using the equations established by OSHA, the incident, frequency, and severity rates are compared from one year (pre- ergonomics program implementation) to the next (post-ergonomics program) in order to determine significant difference between the means utilizing paired comparison statistical t-tests. Also, safety incidents directly attributable to ergonomics hazards and workers\u27 compensation costs are compared between the two years for a significant difference determination. Based on the results of these metrics, the effect of the ergonomics program can be validated. Statistical t-tests were completed on 13 data sets from each year. Of these, the OSHA incident rate, OSHA ergo-related incident rate, workers\u27 compensation costs, total number of ergo-related incidents, total number of OSHA recordable incidents, and total number of illnesses were considered to have a significant difference between 1999 and 2000 (2000\u3c1999 data). The hours worked and number of employees per month for each year also demonstrated a significant difference (2000\u3e1999). The Wilcoxon Signed- Rank test was also performed on nonparametric data such as total number of strains, sprains, and tendonitis cases per year. From this study however, the only data demonstrating a significant difference between years was the total number of sprain illnesses. Therefore, using these overall positive results it can be assumed that the ergonomics program did contribute significantly to the reduction of ergonomics and safety related illnesses in the manufacturing facility used in this study

Beyond Lean and the Working Environment

Lean Production System (LPS) has become very popular among manufacturing industries, services and large commercial areas over the years due to its production increase abilities. However, LPS practices can have both negative and positive impacts in worker’s psychosocial factors like motivation, satisfaction and commitment and physical and psychological health factor like musculoskeletal disorders (MSD) and stress. Since LPS is a very broad term, there is no simple relation between LPS implementation and its consequences over work environment and workers. Therefore, it is necessary to study the different factors that can affect the work environment in each case. A wide variety of LPS practices can have negative and positive impacts on workers. Furthermore, the effects of lean may also depend on the sector and country in which it is implemented. There are no studies in the literature that cover all these effects and analyse them together with the involved environment. In this study, articles were collected in scientific publications in the last 26 years and analysed. Results show that Just-in-Time (JIT) practices are strongly related with negative effects in MSDs and stress caused by intensification of work and increase of control over workers. However, JIT practices such as manufacturing cells can increase job enrichment trough multi-skilling. Respect for people practices can act as buffers to lean practices. Job rotation reduces human effort and work pace trough the increase of recovery time. Workgroups create job support acting as buffers to psychosocial factors. Results show a majority of negative effects in the automotive sector and in countries such as Canada, USA and UK. Scandinavian countries have implemented hybrid forms of Lean which are related to an increase in effects such as motivation and job satisfaction. However, the overall analysis is that the effects of lean on workers depend more on the way companies manage and implement it rather than the countries cultural factors. This study can be useful for managers and leaders who seek to transform traditional enterprises into exemplars of lean success, showing the need to balance lean and good working conditions

Topics in construction safety and health : ergonomic hazards and WMSDs : an interdisciplinary annotated bibliography

"These referenced articles provide literature on construction workers and their risk of ergonomic hazards and work-related musculoskeletal system disorders on the job." - NIOSHTIC-2NIOSHTIC no. 20068246Production of this document was supported by cooperative agreement OH 009762 from the National Institute for Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.Ergonomics-and-WMSDs-annotated-bibliography.pdfcooperative agreement OH 009762 from the National Institute for Occupational Safety and Healt

The effects of Lean intervention (5S) on perceived musculoskeletal workload and perceived hazardous working conditions in a health center pharmacy

The healthcare industry involves a significant level of health and safety risks in various work processes, and healthcare professionals are at risk for work-related musculoskeletal disorders and other health problems. In recent years, Lean has been introduced in healthcare with the goal of eliminating waste and improving efficiency. Lean is also believed to affect the health and safety of workers. The present research studies the effects of Lean (5S) implementation in an acute care pharmacy of a health center. A version of the Dutch Musculoskeletal Questionnaire (DMQ) was used to record the perceived musculoskeletal workload and perceived hazardous working conditions. There were twelve participants from the two participating pharmacies and they were divided into two groups, study and control. The study group underwent Lean transformation in the form of a 5S event. Work sampling was conducted to determine any changes in the existing process in terms of percentage of value added and non-value added activities over the course of the study. Work sampling results did not indicate any significant changes in the percentage of value added and non-value added activities post 5S. The pharmacists and the pharmacy technicians reported a significant reduction in perceived musculoskeletal workload on the wrist after the 5S event. Perceived hazardous working conditions were not reduced after the 5S for either the pharmacists or the pharmacy technicians

Evaluation of the reliability of an ergonomic decision system.

A novel approach deemed the Ergonomic Decision System (EDS) was designed to address the physical requirements of modern industry. The EDS, as the name implies, is a system that uses a series of questions and resulting choices to determine the path to the most appropriate ergonomic analysis tool for a given occupational task. The face validity of the EDS has been established through an extensive review of literature. Reliability was evaluated both within and between subjects. In two facilities, 6 Jobs were chosen based upon both injury and illness data and the differing physical requirements of each. These Jobs were video recorded and two Jobs were randomly chosen. Novice subjects (N = 6) were asked to apply the EDS to one of these jobs prior to being provided the basic ergonomic training. Subsequently, all trained subjects (N = 12) applied the EDS to the same 6 recorded Jobs. The results from the EDS applications were then compared to a criterion measure resulting in a total EDS score which was used to determine subject accuracy. A high overall mean accuracy value of 88.4%, was found with experts and novices varying only slightly with mean scores of 92.6% and 84.3%, respectively. Further, a consensus count was taken from each user for each condition to determine consistency. A good overall mean consensus, between subjects, of 76.9% was found with experts scoring 85% and novice subjects 72%. Also, the results of the pre-post training study indicated strong within subject consensus with an average of 88.9% across novice subjects. Finally, after a minimum of two weeks had passed, all subjects applied the EDS to the second randomly chosen Job. Results of the test-retest condition showed good consensus within subjects with a mean of 94.4%, where experts scored 88.9%, and novice subjects showed perfect consensus. The results of the study effectively establish that the EDS provided sufficient subject consistency and accuracy in directing subjects to the most applicable ergonomic resource across Jobs tested.Dept. of Industrial and Manufacturing Systems Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2006 .D39. Source: Masters Abstracts International, Volume: 45-01, page: 0435. Thesis (M.A.Sc.)--University of Windsor (Canada), 2006