LIFT STRENGTH CAPABILITY OF THAI MALE INDUSTRIAL WORKERS
Keywords:
Lift strength, muscular activityAbstract
The objectives of this study were: 1) to measure lift strengths and muscular activities, and 2) to evaluate the ability of industrial workers to quantify the lifting weights. Lift strengths were recorded using the isometric strength measurement system. Muscular activities in left and right erector spinae were measured by electromyogram. Five heights (floor, knee, knuckle, elbow and shoulder), two reaches (normal and maximum), and three horizontal angles (0, 45, and 90 degrees) were used to define 30 strength measurement locations. The results showed that the maximum strength was 498.49 Newton (N). This value was recorded in the maximum reach at the knuckle height and 0 degree horizontal angle. The greatest muscular activity in erector spinae was found in the maximum reach at the floor height and 0 degree horizontal angle. To evaluate the ability of the workers to quantify the lifting weights, the workers lifted the box and then estimated the weight of the box. It was found that the workers slightly overestimated the weights in most cases. The results of this study can be used to design industrial tasks and workstation in such a manner that the industrial workers can work effectively and safely.
References
Gamberale, F. (1990). Perception of effort in manual material handlings. Scand J. Work Environ Health, 16(1):59-66.
Intaranont, K., Somnasaeng, S., Khokhajaikiat, P., and Charoenchai, N. (1988). Anthropometry and physical work capacity of agricultural and industrial populations in Northeast Thailand. Institute of Research and Development, Khon Kaen University, Thailand, 194p.
MacKinnon, S.N. (1998). Isometric pull force in the sagittal plane. Applied Ergonomics, 29(5):319-324.
Maiti, R. and Ray, G.G. (2003). Study of the variation of peak isometric strength and EMG activity in static field-simulated lifting postures. Int. J. Ind. Erg., 33:109- 122.
Mamansari, D.U. and Salokhe, V.M. (1996). Static strength and physical work capacity of agricultural labourers in the central plain of Thailand. Applied Ergonomics, 27(1):53- 60.
Mital, A. and Kumar, S. (1998). Human muscle strength definition, measurement, and usage: Part I - Guideline for the practitioner. Int. J. Ind. Erg., 22:101-121.
National Institute for Occupational Safety and Health, U.S. (NIOSH). (1997). A Critical Review of Epidemiologic Evidence for Work-Related Musculoskeletal Disorders of the Neck, Upper Extremity, and Low Back. U.S. Department of Health and Human Services, Cincinnati. Publication No. 97-141.
Niempoog, S., Siripakarn, Y. and Suntharapa, T. (2007). An Estimation of Grip Strength during Puberty. J. Med. Assoc. Thai, 90(4): 699-705.
Sanchez, D. and Grieve, D.W. (1992). The measurement and prediction of isometric lifting strength in symmetrical and asymmetrical postures. Ergonomics, 35(1):49- 64.
Warkwick, D., Novak, G., Schultz, A. And Berkson, M. (1980). Maximum voluntary strengths of male adults in some lifting, pushing and pulling activities. Ergonomics, 23(1):49-54.
Wiktorin, C., Selin, K., Ekenvall, L., Kilbom, A. and Alfredsson, L. (1996). Evaluation of perceived and self-reported manual forces exerted in occupational materials handling. Ergonomics, 27(4):231-239.
Xiao, G., Lei, L., Dempsey, P.G., Lu, B., and Liang, Y., (2005). Isometric muscle strength and anthropometric characteristics of a Chinese sample. Int. J. Ind. Erg., 35:674- 679.
