• Journal of the Korean Society of Safety
• /
• v.26 no.3
• /
• pp.69-74
• /
• 2011

Despite most of tasks in manufacturing, construction and agriculture, etc., were currently mechanized and automated, manual materials handling still existed in atypical working condition. In case of manual materials handling, repetitive work, inappropriate working posture, excessive force, contact stress might cause overload, which could lead to work-related musculoskeletal disorders and low back pains. On this basis, the goal of this study is to reveal the effects of various lifting postures of trunk angles and lower extremity postures on maximum holding time(MHT). Twenty two subjects were recruited from a university population. The experiment was designed by a combination of three trunk angle ($0^{\circ}$, $20^{\circ}$, $60^{\circ}$) and three lower extremity postures(straight, bent, kneeling). Before experimental trials, subjects performed MVC(maximum voluntary contraction) exertions in three trunk angles ($0^{\circ}$, $20^{\circ}$, $60^{\circ}$) to calculate 30%MVC at designated postures. In each trial, they were required to hold the handheld load(30%MVC) for a designated posture as long as they could. The results of MVC by trunk angles were measured in $0^{\circ}$ > $20^{\circ}$ > $60^{\circ}$ orders, but those of MHT measured in $20^{\circ}$ > $0^{\circ}$ > $60^{\circ}$ orders. These results showed that straight posture is the ideal working posture in work exerted a strong force for a short time, but the ability to work might be improved in the trunk angle $20^{\circ}$ in work required 30%MVC for a long time. Also, results of MVC and MHT by lower extremity postures measured in straight > bent > kneeling orders.

• Journal of Digital Convergence
• /
• v.11 no.10
• /
• pp.571-576
• /
• 2013

The purpose of this study is to investigate work related diseases in Korean firefighters and to prepare the preventive measure for health management for the firefighters. Structured self-reported questionnaire was distributed to the firefighters. The result revealed that 37.7% of fire fighters had chronic diseases and 12.3% had chronic low back pains. The affected parts included lumbar region(41.5%), shoulder(33.0%), and neck(23.6%). The affected parts caused physical pain and work discomfort for more than a month. A total of 54.1% firefighters visited to the hospital within a year. This results suggest that it is necessary to develop the health promotion program for the prevention of musculoskeletal disease and regular health checkup for the acute disorders caused by workload.

• Journal of the Ergonomics Society of Korea
• /
• v.26 no.2
• /
• pp.157-165
• /
• 2007

The Work-Related Musculoskeletal Disorders (WMSDs) can be occurred by various factors such as repetition, forceful exertions and awkward postures. Especially, occurrences of the WMSDs on the waist and lower limb are reported in workplaces, demanded standing postures for a long time, in service and manufacturing industry. The static and standing postures without movement for a long time increase work loads to the lower limb and the waist. Accordingly, anti-fatigue mat or anti-fatigue insole is used as a preventing device of the WMSDs. However anti-fatigue mats are limited in space and movement. In this study, multi-elastic insoles are designed and shown the effects of the workload reduction for a long time under the standing work. The foot pressures and EMG (Electromyography) are measured at 0 hour and after 2 hours by 6 health students in their twenties. The 6 prototype insoles are designed with three elastic (Low, Medium and High). These insoles are compared with no insole (insole type 7) as control group. The EMG measurement was conducted to waist (erector spinae muscle), thigh (vastus lateralis muscle) and calf (gastrocnemius muscle). The foot pressure is analyzed by mean pressure value and the EMG analysis is investigated through MF (Median Frequency), MPF (Mean Power Frequency) and ZCR (Zero Crossing Rate). The results of the foot pressure show that the multi-elastic insoles had smaller foot pressure value than that of no-insole. Moreover, Insole 2 and Insole 3 have the smallest increasing rate in foot pressure. The EMG results show that the multi-elastic insoles had smaller EMG shift value than that of no-insole in 2 hour, and then shift value shows the smallest value in Insole 2. Therefore, this study presents that the multi-elastic insoles have reducing effects of the work load for a long time standing work in both side of foot pressure and EMG.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3552-3560
• /
• 2012

This study was conducted to find out the complaint rate of musculo-skeletal disorder and its related factors from male manufacturing workers at a nonferrous manufacturing industry. As for the research subjects, 302 workers selected from a nonferrous manufacturer located in Daejeon City, and as for the collection of data, a standardized anonymous questionnaire survey were conducted from May 1, 2011 to June 30, 2011. As a results, the complaint rate of musculo-skeletal disorders by each body part, the symptom of shoulders was 42.7%, the highest rate, followed by the waist, 36.8%, the neck and the hand/wrist/finger, 30.5% respectively, the leg and foot, 30.1% and arm/elbow, 20.9%. The complaint rate of musculo-skeletal disorder for the sociodemographic characteristics was significantly high as survey participants' age and BMI were low and in the group having low subjective health condition. The complaint rate of musculo-skeletal disorder for the health-related behavior characteristics was significantly high in the group having been absent from work due for diseases, in the group having received outpatient services, in the group having been hospitalized for treatment, in the group not having a regular exercise and in the group having insufficient sleeping hours. Finally, the complaint rate of musculo-skeletal disorder for the job-related characteristics was significantly high in the group suffering from the physical burden of their work, in the group working while bending at the waist and in the group carrying out repetitive tasks.

• Journal of the Ergonomics Society of Korea
• /
• v.27 no.1
• /
• pp.53-60
• /
• 2008

The purpose of this study is to provide basic data, such as exerting muscle power of the lower-extremity, EMG test and pressure distribution for designing ergonomic workstation in sitting posture. The exerting muscle power of the lower-extremity was measured by PRIMUS in 4 postures of 90$^{\circ}$, 120$^{\circ}$, 150$^{\circ}$ and 180$^{\circ}$. And performed ANOVA test on Max. and Mean 100%MVC. In EMG test for surveying muscle mobiligation, 5 muscles(Rectus Femoris, Vastus Lateralis, Gastrocnemius, Soleus, Tibialis Anterior) were employed. Additional experiment in pressure distribution in sitting posture by Pliance(16$\time$16 poles), Max. pressure was measured and performed ANOVA test on the results. Concludingly, sitting posture with 120$^{\circ}$ lower-extremity is the best design criterion for ergonomic workstation in sitting posture.

• Journal of the Ergonomics Society of Korea
• /
• v.26 no.4
• /
• pp.25-31
• /
• 2007

The purpose of this study was to investigate the strength and endurance of the deep neck flexor muscles in individuals with work-related neck pain. Subjects consisted of two groups: twenty industrial workers with neck pain and twenty age-matched healthy subjects. To evaluate the strength and endurance of deep cervical flexors, maximum voluntary contractile strength (MVCS) and a sustained time at sub-maximal voluntary contractile strength (SMVCS) (80% and 50% of MVCS) were measured using a pressure biofeedback unit and a stop watch in supine. The MVCS of deep neck flexor muscles was 29.67${\pm}$4.56 in neck pain group and 54.27${\pm}$6.78㎜Hg in normal group. The sustained time at 80% SMVCS was 12.42${\pm}$2.64 seconds and 55.12${\pm}$12.76 seconds in the groups with and without neck pain. The sustained time at 50% SMVCS was 25.40±5.88 seconds and 109.70${\pm}$31.50 seconds in the groups with and without neck pain. The difference of the lower jaw position was 16.75${\pm}$3.57㎜ and 23.03${\pm}$2.51㎜. The MVCS, endurance at the two sub-maximal levels and the difference of the lower jaw position were significantly greater in the group without neck pain than with neck pain (p$<$0.05). The findings indicate that the maximal strength and endurance of the deep neck flexors were decreased in the workers with neck pain compared to those without neck pain. Therefore, it is necessary to include strengthening and endurance exercises of the deep neck flexor muscles in therapeutic program of work-related musculoskeletal disorders involving neck pain.

• Journal of the Korean Society of Safety
• /
• v.36 no.5
• /
• pp.61-70
• /
• 2021

This study aimed to analyze the research trends of the abstract data of ergonomic studies registered in MEDLINE, a medical bibliographic database, using word embedding. Medical-related ergonomic studies mainly focus on work-related musculoskeletal disorders, and there are no studies on the analysis of words as data using natural language processing techniques, such as word embedding. In this study, the abstract data of ergonomic studies were extracted with a program written with selenium and BeutifulSoup modules using python. The word embedding of the abstract data was performed using the word2vec model, after which the data found in the abstract were vectorized. The vectorized data were visualized in two dimensions using t-Distributed Stochastic Neighbor Embedding (t-SNE). The word "ergonomics" and ten of the most frequently used words in the abstract were selected as keywords. The results revealed that the most frequently used words in the abstract of ergonomics studies include "use", "work", and "task". In addition, the t-SNE technique revealed that words, such as "workplace", "design", and "engineering," exhibited the highest relevance to ergonomics. The keywords observed in the abstract of ergonomic studies using t-SNE were classified into four groups. Ergonomics studies registered with MEDLINE have investigated the risk factors associated with workers performing an operation or task using tools, and in this study, ergonomics studies were identified by the relationship between keywords using word embedding. The results of this study will provide useful and diverse insights on future research direction on ergonomic studies.

• Safety and Health at Work
• /
• v.13 no.4
• /
• pp.379-386
• /
• 2022

Emergency medical services (EMS) personnel are at high risk for adverse mental health outcomes during disease outbreaks. To support the development of evidence-informed mitigation strategies, we conducted a scoping review to identify the extent of research pertaining to EMS personnel's mental health during disease outbreaks and summarized key factors associated with mental health outcomes. We systematically searched three databases for articles containing keywords within three concepts: EMS personnel, disease outbreaks, and mental health. We screened and retained original peer-reviewed articles that discussed, in English, EMS personnel's mental health during disease outbreaks. Where inferential statistics were reported, the associations between individual and work-related factors and mental health outcomes were synthesized. Twenty-five articles were eligible for data extraction. Our findings suggest that many of the contributing factors for adverse mental health outcomes are related to inadequacies in fulfilling EMS personnel's basic safety and informational needs. In preparation for future disease outbreaks, resources should be prioritized toward ensuring adequate provisions of personal protective equipment and infection prevention and control training. This scoping review serves as a launching pad for further research and intervention development.

• Journal of Korean society of Dental Hygiene
• /
• v.4 no.2
• /
• pp.225-236
• /
• 2004

It has been suggested in research results thai dental hygienists have high risk of carpal tunnel syndrome, mainly caused by the repeated motion of extensor and flexor or the use of vibration tools, compared to other occupations. To find out the situation of the carpal tunnel syndrome of dental hygienists, who are exposed to work-related musculoskeletal disorders, this study used 132 questionnaires given on May 22, 2004, the period of continuing education of the first half year in the Gwangju Jeonnam area, and obtained the following results. 1. Subjects worked at a dental ciinic(32.6%), a hospital(31.8%), and a public health center(35.6%). Age by work was under 24 in a clinic(17.4%) and a hospital(15.9%), and over 30 in a public health center(35.6%). 2. In practice conducted over one time a day, a scaling accounted for 90.7% in a doctor's office; 595% in a hospital; and 3.0% in a public health center, suggesting significant difference(p<0.01). Pit and fissure sealant accounted for 53.5% in a clinic; 53.2% in a hospital; and 95% in a public health center, also suggesting significant difference(p0.01). 3. Symptoms of carpal tunnel syndrome appeared in a wrist(12.1%), a right hand(14.4%), and a left hand(5.3%). 4. In case of temporary crown practice, symptoms appeared in a wrist(22.0%), a right hand(14.0%), and a left hand(4.0%), suggesting significant difference(p<0.01). The above results showed that 12.1% of dental hygienists was exposed to carpal tunnel syndrome. Thus, it is considered very important that dental hygienists should be given education of the danger of continuous work in certain motions and prevention education of improving repeated position, and make efforts to reinforce self-control ability.

• Journal of the Ergonomics Society of Korea
• /
• v.27 no.1
• /
• pp.45-51
• /
• 2008

The purpose of this survey was to identify ergonomic risk factors of work-related musculoskeletal disorders (MSD) and understand the current MSD risk status in the wholesale/retail industry. The field survey was conducted at 120 wholesale/retail establishments, and the cause of MSD occurred from the national industrial accident statistics by the Ministry of Labor in 2006 was analyzed in terms of company size, a term of work, job title, and cause of occurrence. The numbers of disasters on MSD were 602 which were included 432 disasters who met with low back pain by incident. A checklist was developed by KOSHA to use for the field survey. A total of 419 tasks were identified at the 120 establishments surveyed. The highest frequency was Task 2(45%) which was mostly observed in repetitive work (e.g. displaying, scanning, cutting or wrapping of goods). The second and third were Task 9(34%) and Task 8(14%) which were identified in manual materials handling (e.g. lifting, lowering, carrying or stocking of goods). The results suggest that the three Tasks should be first considered for the control in wholesale/retail industry and that exposure to MSD risk factors in those Tasks should be primarily addressed in order to reduce MSD risk in that industry.