Advanced SearchSearch Tips
Ergonomic Evaluation of Workload in Imbalanced Lower Limbs Postures
facebook(new window)  Pirnt(new window) E-mail(new window) Excel Download
 Title & Authors
Ergonomic Evaluation of Workload in Imbalanced Lower Limbs Postures
Kim, Eun-Sik; Yoon, Hoon-Yong;
  PDF(new window)
Objective: The purpose of this study is to compare the workload level at each lower limbs posture and suggest the ergonomic workstation guideline for working period by evaluating the imbalanced lower limbs postures from the physiological and psychophysical points of view. Background: Many workers like welders are working in various imbalanced lower limbs postures either due to the narrow working conditions or other environmental conditions. Method: Ten male subjects participated in this experiment. Subjects were asked to maintain 3 different lower limbs postures(standing, squatting and bending) with 3 different working conditions(balanced floor with no scaffold, imbalanced floor with 10cm height of scaffold, and imbalanced floor with 20cm height of scaffold). EMG data for the 4 muscle groups(Retus Femoris, Vastus Lateralis, Tibialis Anterior, Gastrocnemius) from each lower limbs posture were collected for 20 seconds every 2 minutes during the 8 minutes sustaining task. Subjects were also asked to report their discomfort ratings of body parts such as waist, upper legs, lower legs, and ankle. Results: The ANOVA results showed that the EMG root mean square(RMS) values and the discomfort ratings(CR-10 Rating Scale) were significantly affected by lower limbs postures and working time(p<0.05). The correlation was analyzed between the EMG data and the discomfort ratings. Also, prediction models for the discomfort rating for each posture were developed using physical condition, working time, and scaffold height. Conclusion: We strongly recommend that one should not work more than 6 minutes in a standing or squatting postures and should not work more than 4 minutes in a bending posture. Application: The results of this study could be used to design and assess working environments and methods. Furthermore, these results could be used to suggest ergonomic guidelines for the lower limbs postures such as squatting and bending in the working fields in order to prevent fatigue and pain in the lower limbs body.
Imbalanced lower limbs posture;EMG data;CR-10 rating;Prediction model;
 Cited by
A Study on Functional Movement Screen and Automobile Worker's Musculoskeletal Disorders, Journal of the Ergonomics Society of Korea, 2016, 35, 3, 125  crossref(new windwow)
Baker, P., Reading, I., Cooper, C. and Coggon, D., "Knee disorders in the general population and their relation to occupation," Occupational and Environmental Medicine, 60(10), pp. 794-797, 2003. crossref(new window)

Basmajin, J. V., "Muscles Alive - Their Functions Revealed by Electromyography." Williams & Wilkins, (1978).

Hong, C.-W. and Kim, Y.-C., "The Evaluation of Workload on Lower Limbs Muscles in Imbalanced Lower Limbs Postures Using EMG for Preventing WMSDs", Journal of the Ergonomics Society of Korea, Vol. 28, No. 3 pp.81-85, 2009. crossref(new window)

Coggon, D., Croft, P., Kellingray, S., Barrett, D., McLaren, M. and Cooper, C., "Occupational physical activities and osteoarthritis of the knee," Arthritis and Rheumatism, 43(7), pp. 1443-1449, 2000. crossref(new window)

Cooper, C., McAlindon, T., Coggon, D., Egger, P. and Dieppe, P., "Occupational activity and osteoarthritis of the knee," Annals of Rheumatology and Diseases, 53(2), pp. 90-93, 1994. crossref(new window)

Gallagher, S., Marras, W. S. and Bobick, T. G., "Lifting in stooped and kneeling postures: effects on lifting capacity, metabolic costs, and electromyography of eight trunk muscles," International Journal of Industrial Ergonomics, 3(1), pp. 65-76, 1988. crossref(new window)

Genaidy, A. M., Barkawi, H. and Christensen, D., "Ranking of static non-neutral postures around the joints of the upper extremity and the spine", Ergonomics, 38(9), 1851-1958, 1995. crossref(new window)

Grandjean, E. and Huunting, W., "Ergonomics of postures - review of various problems of standing and sitting postures," Applied Ergonomics, 8(3), pp.135-140, 1977. crossref(new window)

Lee, I.-S. and Chung, M.-K., "Workload Evaluation of Squatting Work Postures", Journal of the Korean Institute of Industrial Engineers, 24(2), pp. 167-173, 1998.

Jensen, L. K. and Eenberg, W., "Occupation as a risk factor for knee disorders," Scandinavian Journal of Work Environment and Health, 22(3), pp. 165-175, 1996. crossref(new window)

Ministry of Employment and Labor of Korea, The report on occupational accident and disease statistics, 2001-2007.

Nahit, E. S., Macfarlane, G. J., Pritchard, C. M., Cherry, N. M. and Silman, A. J., "Short-term influence of mechanical factors on regional musculoskeletal pain: A study of new workers from 12 occupational groups," Occupational and Environmental Medicine, 58, pp. 374-381, 2001. crossref(new window)

Oberg, T., Sandsjo, L. and Kadefors, R., "Subjective and objective evaluation of shoulder muscle fatigue", Ergonomics, 37(8), 1323-1333, 1994. crossref(new window)

Okunribido, O., "Lower limb MSD-scoping work in help inform advice and research planning," Health and Safety Excutive(HSE), 2009.

Peter, K., "The ABC of EMG - A Practical Introduction to Kinesiological Electromyography." Noraxon INC. USA. (2005).

U.S Department of Labor, Bureau of Labor Statistics, 2001-2007.

van Wely, P., "Design and disease," Applied Ergonomics, 1(5), pp. 262-269, 1970. crossref(new window)

Westgaard, R. H. and Aaråas, A., "Postural muscle strain as a causal factor in the development of musculoskeletal illnesses," Applied Ergonomics, 15(3), pp. 162-174, 1984. crossref(new window)

Zhang, Y., Hunter, D. J., Nevitt, M. C., Xu, L., Niu, J., Lui, L. Y., Yu, W., Aliabadi, P. and Felson, D. T., "Association of squatting with increased prevalence of radiographic tibiofemoral knee osteoarthritis - The Beijing osteoarthritis study" Arthritis and Rheumatism, 50(4), pp. 1187-1192, 2004. crossref(new window)