Risk Of Cumulative Trauma Disorders Research Articles

EVALUATION OF WORK POSTURE USING THE CTD RISK INDEX METHOD TO REDUCE THE RISK OF MUSCLE INJURY IN THE BATIK CAP INDUSTRY

Making stamped batik goes through 5 stages, namely tasting, dyeing color, removing hot and cold tubs, and drying. This process takes place repeatedly for a long time, causing workers to potentially experience musculoskeletal complaints and the risk of Cumulative Trauma Disorders (CTDs). The purpose of this study was to determine whether batik Nilo Tirto workers were at risk for developing CTDs or not. This research was conducted by using a method to determine the level of worker complaints with a Nordic Body Map (NBM) questionnaire. After knowing each class of worker complaints, the CTDs Risk Index method is used to determine the risk score for muscle injury in workers. If the score is > 1, it is relatively unsafe, so it needs improvement. The 2 most significant scores on the CTDs Risk Index worksheet will be analyzed further to determine the risk factors for musculoskeletal use using the PLIBEL Checklist. The results obtained are, there are 2 workstations that have the highest score on the CTDs Risk Index, namely color dyeing and cold bathing. This is caused by awkward body postures when working, repetitive movements, and poor workstation conditions, so the repair needs to be done. The results of this study can be used for improvements to the workstation for dyeing color and cold tubing in the form of design proposals and the work postures of the two workers.

Perbaikan Sistem Kerja Proses Pemasangan Ban Truk dengan Perancangan Peralatan Pendukung Menggunakan QFD dan REBA

PT.X as one of the heavy equipment manufacturing company are producing mining and non-mining transportation product (e.g. Semi Side Tipper (SST) & Dolly). In producing those kinds of products that mostly using tires, there is a process area to do mounting truck tire. Based on interviews and direct observation results, there is a symptom of Cumulative Trauma Disorders (CTD), especially in the low back area. The low back pain experienced by the operators is caused by an awkward posture that resulted from Manual Material Handling (MMH) in this process. Lifting and holding the tire that is located on the floor with diameter 1.2m, height 0.3m, and weight 90 Kg also the reasons why the awkward posture appears during the mounting truck tire process. Using Rapid Entire Body Assessment (REBA), Nordic Questionnaire, and followed by the Quality Function Deployment (QFD) approach for product design are used to do the improvement for the process. In the end, these ergonomics issues are solved by developing material handling tools that can minimize the risk and symptoms of CTDs. It can be shown by initially REBA score is on level 11 (Very High Risk) to level 7 (Medium Risk) and for the Nordic result from 7 body parts that feel discomfort, now it just becomes 1 body parts feel discomfort.

Psychosocial Influences in the Development of Cumulative Trauma Disorders

ABSTRACT Study Design This study is a single-phase, qualitative study using grounded theory methodology. Introduction Cumulative trauma disorders (CTDs) are musculoskeletal disorders that impact health and productivity. CTD risk factors are present in the workplace, home, and community. Occupational and physical therapists specializing in hand and upper extremity rehabilitation (hand therapists) are widely involved with this population. Hand therapists often employ a medical model in the assessment and treatment of these conditions; however, the medical model has not proven to be consistently effective in relieving symptoms or producing a durable return to daily living activities. Purpose of the Study The purpose of this study was to explore the lived experiences of individuals diagnosed with CTD, and investigate the psychosocial phenomena influencing CTD development as an impediment to occupational performance. Methods The principal investigator recruited 11 participants who met specific inclusion criteria, then used semi-structured interviews aimed at exploring the lived experiences of the participants while investigating the psychosocial phenomenon influencing CTD development. Interviews were transcribed and analyzed using a process of constant comparison, up until saturation occurred. Trustworthiness techniques were used in the data analysis phase and included peer reviews and member checking. Findings The findings suggest that many psychosocial factors contribute to the development and impact of CTDs, at both onset of symptoms and throughout the duration of the condition. A significant number of contextual factors influence participants’ function, behavior, relationships, and the course of medical care. Themes derived from the participants’ expressions, included the following: 1) an initial strategy of “work through the pain,” can be detrimental to symptom resolution and leads to progressive failure to meet role expectations, 2) a pervasive notion of CTDs as “an invisible disability,” leaving participants feeling isolated and frustrated when significant others fail to offer support or reject them, 3) participants often delayed reporting symptom development to employers, family members, and medical personnel, risking permanent injury and disability, 4) a “stigma” is attached to CTDs that encourages isolation; however, the social support of even one significant other in a person's life can facilitate adaptation. Discussion and Conclusion All participants experienced hardship because of their conditions; however, two of the eleven participants capably navigated the process, using past experience and support from family and employer to successfully adapt. These findings offer support that CTDs are adaptive disorders. The study's conclusion suggests a new model to describe CTD dysfunction and presents new ways of thinking for clinicians who treat the CTD population.

Hand cumulative trauma disorders in Nigerian custom tailors: the need for redesign of manual scissors

Cutting scissors are important working tools for Nigerian custom tailors (CTs) but its usage apparently does not meet the ergonomics need of these artisans. A survey was carried out amongst CTs using questionnaires to obtain their background social-occupational demographics and observation methods to study their work performance, use of scissors and any cumulative trauma disorder (CTD) in their hands. Thicknesses of various fabrics were measured and comparison between Western world's custom tailoring job and the Nigerian type was done. The results showed some CTD risk factors with finger contusions on the 71 CTs evaluated. The right-hand contusions were traced to the constant usage of unpadded manual scissors with ungloved hands. Disparity between Western and Nigerian tailoring practice may account for the high occurrence of disorders in Nigerian CTs. Since hand dimensions are crucial in the design of hand tools, it is therefore concluded that hand anthropometry of Nigerian CTs and soft padding of manual scissors may mitigate CTD burdens on CTs' hands.

Comparison of subjective comfort ratings between anatomically shaped and cylindrical handles

Most authors have provided diameter recommendations for cylindrical handle design in order to increase performance, avoid discomfort, and reduce the risk of cumulative trauma disorders. None of the studies has investigated the importance of determining the correct handle shape on the subjective comfort ratings, which could further improve the handles' ergonomics. Therefore, new methods based on a virtual hand model in its optimal power grasp posture have been developed in order to obtain customised handles with best fits for targeted subjects. Cylindrical and anatomically shaped handles were evaluated covering ten subjects by means of an extensive subjective comfort questionnaire. The results suggest large impact of the handle shape on the perceived subjective comfort ratings. Anatomically shaped handles were rated as being considerably more comfortable than cylindrical handles for almost all the subjective comfort predictors. They showed that handle shapes based on optimal power grasp postures can improve subjective comfort ratings, thus maximising performance. Future research should consider real conditions, since the comfort ratings can vary based on the specific task and by the tool selected for the task.

The Study of Muscle Fatigue and Risks of Musculoskeletal System Disorders from Text Inputting on a Smartphone

Objective: This study aims to analyze and evaluate fatigue in upper trapezius muscles of adults when inputting text on a smart phone, thereby examining the risk of cumulative trauma disorders in the musculoskeletal system of the upper extremity. Method: Forty-five healthy adults were divided equally into three groups: a smartphone group, a notebook group, and a desktop group. A surface electromyogram was placed on the upper trapezius muscle of each participant, after which they inputted text for ten minutes within an ergonomic setting; their side posture was recorded on video and analyzed. Results: The spectral edge frequency values for the smartphone group, as recorded from the upper right trapezius muscles on the surface electromyogram, showed a significant decrease(p<.05). Regarding the RULA, all three groups had results indicating

Tool-handle design based on a digital human hand model

A significant part of manual work is still done using hand-tools. Therefore, a correct design is crucial for preventing upper-extremity musculoskeletal disorders, such as carpal tunnel syndrome, hand-arm vibration syndrome, tendonitis, etc. When considering the ergonomics of a hand-tool, in addition to its main functionality, the most important part is the tool's handle. Most of the authors have considered cylindrical handles and provided guidelines and mathematical models for determining optimal diameters in order to maximise finger-force exertion, comfort, contact area, thus minimising the chances of cumulative trauma disorders (CTD). However, they have not taken into account the shape of the hand during optimal power-grasp posture when determining the tool-handles' shapes, which could additionally improve the handles' ergonomics. In order to overcome this limitation, we have developed an anatomically accurate static digital human-hand model (DHHM). The developed DHHM allows direct tool-handle modelling and does not require an iterative design process when designing a tool-handle with improved ergonomics. In order to develop DHHM, anthropometric measurements on ten subjects were performed for the manufacturing of corresponding optimal cylindrical pre-handles with variable diameters for each finger. Outer hand moulds were manufactured based on the pre-handles for obtaining the shape of the hand with skin and subcutaneous tissue undeformed. Magnetic resonance imaging was conducted with the outer hand moulds attached, and segmentation and 3D reconstruction were performed on the images to obtain the DHHMs for each subject. Tool-handles based on DHHM were then obtained within common Computer-Aided Design software. Measurements on the handles based on the DHHM have shown that they provide; on average; an over 25% higher contact area compared to the corresponding cylindrical handle. With higher contact area and anatomical shape of the handle, extensive deformation of the soft tissue can be avoided, thus preventing excessive load on the hand. Subjects also compared these DHHM handles with cylindrical handles regarding perceived subjective comfort-rating. It was shown that those tool handles based on the DHHM provided a higher overall comfort-rating compared to cylindrical handles. It has also been demonstrated that anatomically shaped tool-handles based on the developed DHHM can improve user performance and lower the risk of CTD. Relevance to industryThis paper introduces methods for developing a static DHHM for an optimal power-grasp posture by directly modelling a tool-handle with improved ergonomics. It also demonstrates that anatomically-shaped tool-handles based on the developed DHHM with optimal power-grasp posture increases the contact area and the subjective comfort-rating, thus increasing user performance and lowering the risk of CTD.

Cumulative trauma disorders among California veterinarians

The prevalence of cumulative trauma disorders (CTDs) in veterinarians has not been adequately studied. A questionnaire was sent to 2,000 California veterinarians in 1997; the return rate was 73% (n = 1,415). Ninety-six percent (1,353) of the respondents were professionally active and were included in the analyses. Sixty-four percent were male and 90% were working full-time. One-fourth of the respondents reported a CTD during their career that required treatment or restricted usual activities. Two-thirds of those reporting CTDs reported chronic or residual problems. In a multivariate regression analysis female sex, working full-time, rectal palpations, and large animal practice were significant risk factors for CTDs. Being in large animal practice increased the CTD risk for both women and men whether they worked full or part-time. CTD risk was highest in women working full-time and doing 80% rectal palpations. Preventive methods to attenuate the risk of CTDs especially in large animal practice should be investigated.

Using practical ergonomic evaluations in the restaurant industry to enhance safety and comfort: a case study

Restaurant employees must deal with loud noise, busy environments, difficult customers, heavy, awkward, sharp, and hot objects, repetitive motions, and stress on various joints, all of which can lead to fatigue, sudden accidents, and longterm musculoskeletal injury. The goal of this case study was to assess the risk of injuries and accidents from conducting various tasks in the restaurant, specifically carrying/lifting, table management, and polishing silverware. The nine participants were servers at a local country club restaurant. Physical workload was measured by a scale of physical exertion. Cognitive workload was assessed, as well as cumulative trauma disorder risk. Overall results show that there is sufficient risk in some of the tasks to warrant concern. Specific results are discussed, as well as recommendations for improved safety.

Computer Use, Workstation Design Training and Cumulative Trauma Disorders in College Students

Currently, very little is known about computer use in college students, associated Cumulative Trauma Disorders (CTDs) and musculoskeletal discomfort, or the impact and availability of proper workstation design education and training in this population. Given the expanding use of technology in university settings, it is important to determine how computer use may be causing pain and discomfort for college students, whether workstation education and training is being provided to this population, and whether such education, if provided, is effective. Five-hundred twelve college students completed a survey on health and computer usage. The most frequently reported disorders related to health were eyestrain affecting nearly 85% and, upper back and neck pain affecting 70% of computer users. Only 26.6% of the sample indicated receiving training on workstation design. Identifying college students at risk for CTDs and other musculoskeletal discomforts provides a prime opportunity for health education professionals to intervene at an early stage.

Cumulative trauma disorder risk for children using computer products: results of a pilot investigation with a student convenience sample.

Cumulative trauma disorder is a major health problem for adults. Despite a growing understanding of adult cumulative trauma disorder, however, little is known about the risks for younger populations. This investigation examined issues related to child/adolescent computer product use and upper body physical discomfort. A convenience sample of 212 students, grades 1-12, was interviewed at their homes by a college-age sibling or relative. One of the child's parents was also interviewed. A 22-item questionnaire was used for data-gathering. Questionnaire items included frequency and duration of use, type of computer products/games and input devices used, presence of physical discomfort, and parental concerns related to the child's computer use. Many students experienced physical discomfort attributed to computer use, such as wrist pain (30%) and back pain (15%). Specific computer activities-such as using a joystick or playing noneducational games-were significantly predictive of physical discomfort using logistic multiple regression. Many parents reported difficulty getting their children off the computer (46%) and that their children spent less time outdoors (35%). Computer product use within this cohort was associated with self-reported physical discomfort. Results suggest a need for more extensive study, including multiyear longitudinal surveys.

Cumulative trauma disorder risk for children using computer products: results of a pilot investigation with a student convenience sample

Objectives Cumulative trauma disorder is a major health problem for adults. Despite a growing understanding of adult cumulative trauma disorder, however, little is known about the risks for younger populations. This investigation examined issues related to child/adolescent computer product use and upper body physical discomfort. Methods A convenience sample of 212 students, grades 1-12, was interviewed at their homes by a college-age sibling or relative. One of the child's parents was also interviewed. A 22-item questionnaire was used for data-gathering. Questionnaire items included frequency and duration of use, type of computer products/games and input devices used, presence of physical discomfort, and parental concerns related to the child's computer use. Results Many students experienced physical discomfort attributed to computer use, such as wrist pain (30%) and back pain (15%). Specific computer activities-such as using a joystick or playing noneducational games-were significantly predictive of physical discomfort using logistic multiple regression. Many parents reported difficulty getting their children off the computer (46%) and that their children spent less time outdoors (35%). Conclusions Computer product use within this cohort was associated with self-reported physical discomfort. Results suggest a need for more extensive study, including multiyear longitudinal surveys.

Proof That Ergonomics Works: Combined Results of over 100 Independent Ergonomic Intervention Studies

In an innovative effort to reduce the incidence and severity of cumulative trauma disorder (CTD) claims in Ohio, the BWC has established the CTD Safety Grants program. Employers can receive funds to incorporate ergonomic principles into their workplace. In return, the employers receiving grants provide data to BWC regarding the effectiveness of their interventions. A risk factor checklist was used to rate 306 tasks before and after ergonomic interventions. Also, CTD incidence rates, lost days rates, and turnover rates were measured before and after ergonomic interventions at 126 companies. The data indicate a reduction in risk factor scores of 41.7% (p&lt;0.0001) and a reduction in lost day rates of 42.3% (p&lt;0.005) after implementing ergonomic interventions. These data suggest that engineering controls designed to reduce or eliminate worker exposure to CTD risk factors will reduce the number and severity of CTDs.

Ergonomic design and evaluation of a new VDT workstation chair with keyboard–mouse support

A new-concept VDT workstation chair with an adjustable keyboard/mouse support was proposed to minimize the physical discomfort and the risk of cumulative trauma disorders (CTDs) at work sites. A three-dimensional human modeling tool (SAFEWORK ®) was used to design the new chair which satisfies the anthropometric specifications of the Korean population. Based upon the result of 3-D graphical simulations, a mock-up chair was constructed with an adjustable keyboard/mouse support directly attached to the chair body. An experiment was conducted to compare the new workstation chair to a conventional computer chair without a keyboard–mouse support by measuring muscle fatigue and subjective discomfort. Six volunteer subjects participated in six 1-hour word-processing sessions with two different chairs and three different work postures. Statistical results indicated that the new-concept VDT chair generally improved subjective comfort level and reduced fatigue in the finger flexor/extensor and the low back muscles. Implications of the new design and suggestions for further development are addressed. Relevance to industry The proposed VDT chair in this study can be used by certain VDT users such as telephone operators who are potentially exposed to CTDs. Since the number of computer users has greatly increased, the market share of better-designed VDT chairs is expected to increase rapidly. Moreover, the new VDT chair can impact design and manufacturing industries that make new products and accessories which support the new VDT environment.

Ergonomic analysis of grapevine pruning and wine harvesting to define work and hand tools design requirements

Knowledge of the stress-strain analysis while grapevines pruning and wine harvesting in vineyards will make a significant contribution towards reducing the risk of cumulative trauma disorders (CTD) in the upper limbs of vineyard workers. The stress-strain analysis in field and laboratory studies show that pruning grapevines and wine harvesting involves a combination of dynamic and sensorimotoric work, and also a high incidence of ergonomically undesirable postures of the trunk, the upper limbs and the head irrespective of cutting tools used. The information obtained can be applied in the ergonomic redesign of pruning tasks and pruning tools to reduce incidence of trauma.

Finger motion, wrist motion and tendon travel as a function of keyboard angles

Objective. This study assessed the impact of keyboard angles (in terms of Pitch, Roll and Yaw) on tendon travel and wrist and finger joint kinematics for the flexor digitorum profundus and flexor digitorum superficialis. Design. A repeated measures, laboratory study was conducted. Independent variables were three Pitch angles, three Roll angles, three Yaw angles, and three keyboard separation distances. Dependent variables were tendon travel, wrist deviation, wrist and finger joint kinematics, and Borg comfort rating. Background. The increased usage of computers and the risk of cumulative trauma disorders have led to the development of alternate keyboards. This study is a biomechanical assessment of several keyboard designs. Methods. Lightweight wrist and finger goniometers were used to measure motion of the wrist in three planes, and for three finger joints. Fifteen experienced typists (eight women, seven men) typed a standard text on 30 keyboard conditions. Regression equations were used to calculate tendon travel from joint positions. Results. Tendon travel is sensitive to changes in Pitch, Roll and Yaw angles with ∼13% difference between the minimal and maximal tendon travel. A flat keyboard produced more tendon travel than keyboards with greater Pitch and Roll angles. Conclusions. There is a trade-off between wrist and finger positions; as the wrist extends more, the finger joints flex more to compensate. Keyboards imposed different trade-offs between the wrist and finger positions , affecting the overall tendon travel. Relevance Alternate keyboard designs can significantly affect tendon travel and may address reduced repetitiveness in typing by reducing the amount of tendon travel.

Design and performance of a manual task evaluator

The risk factors of high repetition, high force exertions, and awkward postures have been recognized as increasing the risk of cumulative trauma disorders of the upper extremities in certain jobs and tasks. Measurement of the reactive forces associated with hand tool use, an important component of an ergonomic evaluation, can be difficult in the field. The forces associated with powered hand tools have been measured at the object being worked upon, but few instances of direct instrumentation of non-powered hand tools have been reported. A system for field measurement of manual tasks is presented. System configuration and performance characteristics are detailed as well as the development rationale, system capabilities and limitations.

Measurement of cumulative trauma disorder risk in clerical tasks using fuzzy linear regression

Cumulative trauma disorders (CTDs) of the upper body have been identified as one of the fastest growing workplace hazards. The specific combination and significance of risk factors contributing to CTDs of the hand and forearm is still lacking, and developing methodologies to quantify the relationships of risk factors is greatly needed. Furthermore, the nature of CTDs and variability among individuals creates an environment where an array of uncertainty exists. The purpose of this research is to develop a fuzzy linear regression model to predict the relationship of known risk factors to the onset of CTDs. 27 keyboard users (22 for model building and 5 for model validation) participated in the study. Knowledge acquisition was performed through extensive literature analysis and interviews with two CTD experts. The model was constructed in a modular fashion with four fuzzy modules being constructed to represent the risk associated with the task, anthropometrics, joint deviation and personal factors. These modules were combined to represent an overall risk level and a final model for prediction of CTD risk. The results indicate that fuzzy linear regression is a useful technique for addressing the uncertainty associated with the definition and modeling of CTD risk factors.

Development of a cumulative trauma disorder risk assessment model for the upper extremities

A cumulative trauma disorders (CTD) risk assessment model was developed for predicting injury incidence rates. The model is unique in that it uses quantitative data such as hand motion frequencies and forces together to obtain a frequency factor score that is reflective of the strain imposed on the muscles and tendons of the wrist. Gross upper extremity postures are included in a posture factor score and various minor job stressors are included as a miscellaneous factor score. The individual frequency, posture and miscellaneous scores were regressed against CTD incidence rates for 24 jobs in a garment sewing and a printing company to yield weights for a predicted incidence rate or risk index. The miscellaneous score was not a significant predictor ( p>0.05) in determining incidence rates and thus was dropped from the model. The results showed that the model was best suited for job tasks with cycle times greater than 4 s. The final best fit model ( p<0.001) explained 52.3% of the variance in predicted incidence rates and may be a useful tool in identifying jobs at risk for cumulative trauma disorders. Relevance to the industry The CTD risk assessment model predicts CTD incidence rates or a relative risk potential for industrial jobs based on task and hand motion parameters. This allows appropriate medical and engineering personnel to intervene quickly to redesign the risky jobs and thus potentially reduce the injuries and medical costs.

Quantitative biomechanical analysis of wrist motion in bonetrimming jobs in the meat packing industry

This study was motivated by the serious impact that cumulative trauma disorders (CTDs) of the upper extremities have on the meat packing industry. To date, no quantitative data have been gathered on the kinematics of hand and wrist motion required in bone-trimming jobs in the red-meat packing industry and how these motions are related to the risk of CTDs. The wrist motion of bone-trimming workers from a medium-sized plant was measured, and the kinematic data were compared to manufacturing industry's preliminary wrist motion benchmarks from industrial workers who performed hand-intensive, repetitive work in jobs that were of low and high risk of hand/wrist CTDs. Results of this comparison show that numerous wrist motion variables in both the left and right hands of bone-trimming workers are in the high-risk category. This quantitative analysis provides biomechanical support for the high incidence of CTDs in the meat packing industry. The research reported in this paper established a preliminary database of wrist and hand kinematics required in bone-trimming jobs in the redmeat packing industry. This kinematic database could augment the industry's efforts to reduce the severity and cost of CTDs. Ergonomics practitioners in the industry could use the kinematic methods employed in this research to assess the CTD risk of jobs that require repetitious, hand-intensive work.