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

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Effects of Touchpad &Buttons Positions in a Laptop Computer on EMG Amplitude and Median Frequency of Muscles Relating to Wrist and Shoulder

랩탑 컴퓨터 터치패드와 클릭버튼 위치에 따른 손목과 어깨 부위 근육의 EMG 진폭 및 중앙 주파수 변화

  • Han, Seung Jo (Industrial Engineering Department, Dankook University) ;
  • Kim, Sun-Uk (Industrial Engineering Department, Dankook University) ;
  • Koo, Kyo Chan (Industrial Engineering Department, Dankook University)
  • 한승조 (단국대학교 산업공학과) ;
  • 김선욱 (단국대학교 산업공학과) ;
  • 구교찬 (단국대학교 산업공학과)
  • Received : 2012.11.28
  • Accepted : 2013.03.07
  • Published : 2013.03.31
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Abstract

The objective of this study is to investigate the association between touchpad &buttons locations in a laptop computer and EMG amplitude and median frequency in muscles related with wrist and shoulder. Based on previous studies it was shown how abductions in wrist and shoulder could cause musculoskeletal disorders in those body parts, on which research hypotheses were established. Touchpad &buttons positions consisted of bottom center(BC), bottom center with $45^{\circ}$ rotation counterclockwise(BCR), and bottom right(BR). 10 subjects performed the task that required only touchpad &buttons usage with their preferred hand and EMG amplitude and median frequency data were recorded during 5min and analyzed afterwards. Upper trapezius and flexor carpi ulnaris were selected as target muscles. The results showed that in flexor carpi ulnaris BC resulted in greater amplitude and less median frequency than BCR and BR, but there was no significant difference between BCR and BR. In upper trapezius BC and BCR induced higher amplitude and lower median frequency than BR, but the significant difference between BC and BCR was not observed. Those phenomena occurred since BC gave rise to both wrist and shoulder abduction, BCR caused only shoulder one, and BR did not lead to abductions in both wrist and shoulder.

본 논문의 목적은 랩탑 컴퓨터의 터치패드 및 두 개의 클릭 버튼 위치에 따른 손목과 어깨 부위 근육의 EMG 진폭 및 중앙 주파수 변화를 알아보는 것이다. 기존 연구결과를 바탕으로 손목과 어깨의 외전현상이 근골격계질환으로 이어지는 메커니즘을 살펴보고, 이를 토대로 연구가설이 설정되었다. 실험에서 터치패드 및 클릭버튼의 위치는 기존의 중앙 아래(bottom center, BC)와 중앙 아래에 위치하지만 $45^{\circ}$ 반시계방향으로 회전된 방식(bottom center with rotation, BCR), 그리고 회전없이 중앙 오른쪽에 위치한 경우(bottom right, BR)가 비교되었다. 10명의 피실험자는 오른 손으로 5분 동안 터치패드 및 두 개의 버튼을 이용하는 task를 각각의 시행하는 동안 EMG 진폭과 중앙 주파수가 측정되었다. 손목 부위의 근육은 척측수근굴근, 어깨부위의 근육은 위쪽 승모근이 선정되었다. 실험결과 손목부위에서는 BC의 경우가 진폭은 크게 나타나고 중앙 주파수는 작게 나타났으며, 어깨부위에서는 BC와 BCR이 BR보다 진폭은 크고 중앙 주파수는 작게 나타났다. 또한, 손목부위에서는 진폭과 중앙 주파수 모두에서 BCR과 BR의 차이가 유의하게 나타나지 않았고, 어깨부위에서는 BC와 BCR에서의 차이가 나타나지 않았다. 이러한 결과는 BC에서는 손목과 어깨의 외전이 동시에 나타나고, BCR은 어깨의 외전만, 그리고 BR은 손목과 어깨에서 외전이 모두 나타나지 않기 때문이다.

Keywords

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