Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

Comparison of Peak EMG Amplitude on Low Back Muscles according to Asymmetric Load Center of Gravity and Trunk Lateral Bending while Lifting

들기 작업시 중량물의 비대칭 무게중심 및 상체 옆으로 기울임에 따른 허리근육의 Peak EMG 진폭 비교

  • Han, Seung Jo (Department of Industrial Engineering, Dankook University) ;
  • Kim, Sun-Uk (Department of Industrial Engineering, Dankook University)
  • 한승조 (단국대학교 산업공학과) ;
  • 김선욱 (단국대학교 산업공학과)
  • Received : 2012.07.11
  • Accepted : 2012.10.11
  • Published : 2012.10.31
Download PDF
⟨ Previous Next ⟩

Abstract

This study was aimed at the relationship between peak EMG amplitude on low back muscles acting on L5/S1 and load center of gravity, trunk lateral bending while lifting an object. Musculoskeletal disorders including low back pain can occur even when handling heavy objects only once as well as when doing non-heavy materials repeatedly. 11 male subjects with average 23 age were required to lift a 15.8kg object symmetrically three times. Peak EMG amplitudes on 6 muscles related with L5/S1 were recorded and analyzed. The lifting conditions consisted of lifting symmetric load with no trunk lateral bending, asymmetric load with no trunk lateral bending, and asymmetric load with trunk lateral bending to the load center of gravity within an object. The results showed that peak EMG amplitude on back muscles contralateral to load center of gravity was observed greater in comparison with the symmetric load. Also, in case of lifting asymmetric load the posture with trunk lateral bending increased peak EMG amplitude on muscles contralateral to load center of gravity more than with no trunk lateral bending. This research can be used as one administrative intervention in order to reduce the low back pain incidence with suggesting workers that they keep the trunk not bending to load center of gravity if possible when lifting a heavy asymmetric object.

본 연구의 목적은 중량물 들기 작업시 비대칭 무게중심과 상체 옆으로 기울임 여부가 어떻게 L5/S1 주변 허리 근육의 Peak EMG 진폭에 영향을 미치는지를 알아보는 것이다. 요통을 포함한 근골격계질환은 무겁지 않은 물체의 지속적인 반복 취급뿐만 아니라, 일회성의 커다란 부하도 신체 조직의 부담으로 작용하여 발생할 수 있다. 11명의 20대 대학생 남성은 15.8kg의 물체를 들어올리는 Task를 3회 실행하였다. 이 때 대칭 무게중심의 물체를 상체를 기울이지 않고 들어 올리는 경우, 비대칭 무게중심의 물체를 상체를 기울이지 않고 들어 올리는 조건, 그리고 비대칭 무게중심의 물체를 상체를 기울여서 들어 올리는 경우에 따라 6개의 L5/S1 주변의 근육들로부터 Peak EMG 진폭이 수집되어 분석되었다. 결과는 비대칭 무게중심을 지닌 물체 취급시 무게중심에서 먼 쪽의 허리 근육에서 Peak EMG 진폭이 발생하고, 그 진폭의 크기는 대칭 무게중심 물체를 취급하는 경우보다 크게 나타났다. 또한, 비대칭 무게중심의 물체를 취급할 경우 물체나 상체를 물체의 무게중심 방향으로 기울이는 것은 기울이지 않을 때보다 대측성 등근육에서 Peak EMG 진폭 증가시켰다. 이러한 연구 결과는 비대칭 무게중심의 중량물을 들어 올리는 작업에서 요통 발생을 예방하기 위한 행정적인 조치로써 가능하면 상체를 전두면 기준으로 기울이지 않는 작업자 자세 조언이 필요함을 말해준다.

Keywords

References

  1. Kim, J., "Policies and strategies for preventing musculoskeletal disorders of workers in industries", Seminar for Industrial Safety, Korean Association of Certified Exercises Professionals, 2012.
  2. "Analysis of industrial accidents at 2010" Ministry of Employment and Labor of Korea, 2011.
  3. Kim, H., "Comparison of muscle strength for one hand and two hands lifting activity", Journal of the Ergonomics Society of Korea, 26(2), 35-44, 2007. https://doi.org/10.5143/JESK.2007.26.2.035
  4. Han, S. J., and Kim, S., "The analysis of low back loading and muscle fatigue while lifting an asymmetric load", Journal of Society of Korea Industrial and Systems Engineering, 35(2), 30-36, 2012.
  5. Han, S. J., and Kim, S., "The model from asymmetric load to low back loading", Proceedings of the 2012 Spring Conference of the Society of Korea Industrial and Systems Engineering, 29-34, 2012.
  6. Meyers, B. M., and Keir, P., "Trunk muscle response to lifting unbalanced loads with and without knowledge of centre of mass", Clinical Biomechanics, 18, 712-720, 2003. https://doi.org/10.1016/S0268-0033(03)00121-9
  7. McGill, S., "The biomechnics of low back pain: implications on current practice in industiral and the clinic", Bomechanics, 30(5), 465-575, 1997. https://doi.org/10.1016/S0021-9290(96)00172-8
  8. Marras, W. S., "Occupational low back disorder causation and control, Ergonomics, 43(7), 880-902, 2000. https://doi.org/10.1080/001401300409080
  9. Roy, S. H., De Luca, C. J., Snyder-Mackler, L. Emley, M. S., Crenshaw, R. L., and Lyons, J. P., "Fatigue, recovery, and low back pain in varsity rowers", Medicine and Science in Sports and Exercise, 22(4), 463-469, 1990.
  10. Seroussi, R. E., and Pope, M. H., "The relationship between trunk muscle electromyography and lifting moments in the sagittal and frontal planes", Biomechanics, 20(2), 135-146, 1987. https://doi.org/10.1016/0021-9290(87)90305-8
  11. Nordin, M., Andersson, G. B. J., and Pope, M. H., Musculoskeletal Disorders in the Workplace 2nd Edition, Mosby-Year Book Inc., Missouri, 1997.
  12. Coorevits, P. L. M., Danneels, L. A., Ramon, R. Van Audekercke., Cambier, D. C., and Vanderstaeten, G. G., "Statistical modeling of fatigue-related electromyographic median frequency characteristics of back and hip muscles during a standardized isometric back extension test", Journal of Electrophyography and Kinesiology, 15, 444-451, 2005. https://doi.org/10.1016/j.jelekin.2005.02.002
  13. Shin, G., and D'Souza, C.,"EMG activity of low back extensor muscles during cyclic flexion/extension", Journal of Electromyograhpy and Kinesiology, 20(4), 742-749, 2010. https://doi.org/10.1016/j.jelekin.2010.03.002
  14. Bigland, B., and Lippold, O. C. J., "The relation between force, velocity and integrated electrical activity in human muscles", Journal of Physiology, 123, 214-224, 1954. https://doi.org/10.1113/jphysiol.1954.sp005044
  15. Lavender, S. A., Andersson, G. B. J., Schipplein, O. D., and Fuentes, H. J., "The effects of initial lifting height, load magnitude, and lifting speed on the peak dynamic L5/S1/ moments", International Journal of Industrial Ergonomics, 31, 51-59, 2003. https://doi.org/10.1016/S0169-8141(02)00174-9
  16. Cram, J. R., and Steger, J. C., "EMG scanning in the diagonosis of chronic pain", Biofeedback and self-regulation, 8(2), 223-241, 1983.
  17. Reid, D. A., and McNair, P. J., "Factors contributing to low back pain in rowers", Br. j. Sports Med., 34(5), 321-322, 2000. https://doi.org/10.1136/bjsm.34.5.321
  18. Roy, S. H., De Luca, C. J., Snyder-Mackler, L. Emley, M. S., Crenshaw, R. L., and Lyons, J. P., "Fatigue, recovery, and low back pain in varsity rowers", Medicine and Science in Sports and Exercise, 22(4), 463-469, 1990.