목적 : 본 연구는 완전척수손상자(C5∼C6) 3명을 대상으로 목과 상지의 근활성도, 근골격계의 피로인지도, 그리고 보조도구로 인한 작업수행도와 만족도의 변화를 측정하여 휠체어용 키보드 작업대의 효과를 알아보고자 실시되었다. 연구방법 : 3명의 척수손상자는 손바닥 지지용 키보드 포인터를 착용한 채 두 가지 작업대(일반책상, 휠체어용 키보드 작업대)에서 5분간 초 당 1타 정도의 속도로 문서 입력 작업을 실시하였다. 실험 동안 목세움근, 위 등세모근, 중간 등세모근, 그리고 손목 폄근군의 근활성도(%RVC)를 표면근전도로 측정하였다. 근골격계의 불편함은 Borg RPE를 이용하여 측정하였으며, COPM은 휠체어용 키보드 작업대의 작업수행 증진도와 만족도를 알아보고자 사용하였다. 결과 : 휠체어용 키보드 작업대를 사용한 결과 목, 어깨, 그리고 손목폄근군의 근활성도가 감소하였다. 또한 피로인지척도 점수가 감소하였으며 COPM의 작업수행도와 만족도도 증가하였다. 결론 : 일반책상과 휠체어용 키보드 작업대를 비교한 결과, 척수손상자의 키보드 입력 작업시 휠체어용 키보드 작업대가 유용 하였다. 이러한 과제 조정은 척수손상자의 상지 통증과 누적외상성 질환을 예방하기 위한 인간공학적 접근을 기초로 이루어져야 한다. 차후 연구에서는 보다 다양한 기능수준의 척수손상자를 위한 인간공학 도구의 개발과 객관적 효과 검증이 필요하다.

목적 : 본 연구는 상위흉수손상군, 하위흉수손상군, 정상군을 대상으로 체간과 상지의 컴퓨터 사용과 관련된 여덟 가지 근육의 활성도를 측정하여 흉수손상자에게 적절한 키보드의 위치를 제시하고자 실시되었다. 연구방법 : 연구대상자는 미국 척수 손상 협회(American Spinal Injury Association; ASIA) A 또는 B의 흉수손상자 중 상위흉수손상자(T2-T8) 9명, 하위흉수손상자(T9-T12) 11명, 그리고 정상인 9명이었다. 적절한 키보드의 위치를 알아 보고자 두 가지 위치 즉, 팔꿈치 굽힘 100°위치와 팔꿈치 굽힘 70°위치에서 근활성도를 측정하였다. 모든 대상자는 2분간 메트로놈의 박자에 맞춰 키보드 중간열의 키를 1초에 4타의 속도로 타이핑하였으며 이때 표면근전도기를 이용하여 목과 어깨의 목세움근, 위등세모근, 앞어깨세모근, 뒤세모근, 중간등세모근과 손목폄근군, 그리고 척수손상자의 체간유지 보조근육인 넓은 등근과 큰가슴근의 근활성도(%RVC)를 측정하였다. 결과 : 상·하위흉수손상군의 측정치는 정상인과 동일하게 팔꿈치 굽힘 100°의 자세에 비해 팔꿈치 굽힘 70°인 위치에서 위등세모근, 손목폄근군, 앞어깨세모근의 활성도가 유의하게 낮게 나타났다. 또한 하위흉수손상군의 경우 정상인과 다르게 팔꿈치 굽힘 100°높이에서 목세움근과 넓은등근의 활성도가 유의하게 증가하였다. 결론 : 흉수손상자의 체간과 상지의 근긴장도를 감소시키기 위해 적절한 키보드 위치는 팔꿈치 굽힘 70°정도의 높이였다. 차후 연구에서는 보다 많은 척수손상자를 대상으로 장시간의 포괄적 컴퓨터 작업을 적용하여 장애특성에 적합한 VDT 환경을 파악하는 연구가 필요할 것으로 사료된다.

In order to prevent upper extremity musculoskeletal disorders, effective keyboard selection is an important consideration. The aim of this study was to compare upper extremity muscle activity according to transverse plane angle changes during vertical keyboard typing. Sixteen healthy men were recruited. All subjects had a similar typing ability (rate of more than 300 keystrokes per minute) and biacromion and forearm-fingertip lengths. Four different types of keyboard (vertical keyboard with a transverse plane angle of 60˚, 90˚, or 120˚, and a standard keyboard) were used with a wrist support. The test order was selected randomly for each subject. Surface electromyography (EMG) was used to measure upper extremity muscle activity during a keyboard typing task. The collected EMG data were normalized using the reference contraction and expressed as a percentage of the reference voluntary contraction (%RVC). In order to analyze the differences in EMG data, a repeated one-way analysis of variance, with a significance level of .05, was used. Bonferroni correction was used for multiple comparisons. There were significant differences in the EMG amplitude of all seven muscles (upper trapezius, middle deltoid, anterior deltoid, extensor carpi radialis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris) assessed during the keyboard typing task. The mean activity of each muscle had a tendency to increase as the transverse plane angle increased. The mean activity recorded during all vertical keyboard typing was lower than that recorded during standard keyboard typing. There was no significant difference in accuracy and error scores; however, there was a significant difference between transverse plane angles of 60˚ and 120˚ with regard to comfort. In conclusion, a vertical keyboard with a transverse plane angle of 60˚ would be effective in reducing muscle activity compared with vertical keyboards with other transverse plane angles.

With the introduction of the video display terminal (VDT), the efficiency and productivity of work has improved. However, VDT syndrome is threatening the health of workers as a side effect of prolonged use of a VDT. Among various VDT syndromes, the musculoskeletal disorder, especially, the cumulative trauma disorder (CTD) is the common research topic related with upper extremities function. The aim of this study was to investigate the effect of the wrist-hand orthosis (WHO) on fatigue in middle deltoid, anterior deltoid, serratus anterior, and upper trapezius during one-hour computer keyboard typing. Twelve healthy subjects participated in this study. Surface electromyography was used to assess the localized muscle fatigue (LMF), and the LMF was calculated at 10 minutes, 20 minutes, 40 minutes, and 60 minutes in each muscle, with and without the WHO. Data were analyzed by paired t-test with a level of significance of .05. The results of this study are as follows: 1) At 10 minutes, the LMF decreased significantly with applied WHO in the middle deltoid, anterior deltoid, and upper trapezius (p=.001, p=.026, p=.019, respectively). 2) As the computer keyboard typing period increased, there were no significant LMF differences, except for the upper trapezius. Therefore, it can be concluded that the WHO can be applied to decrease the LMF for the initial 10 minute period in the middle deltoid, anterior deltoid, and upper trapezius' but that the long term effect of WHO in reducing the LMF was proven only in upper trapezius during continued computer keyboard typing.

There were two purposes of this study. The first was to research the effects of standard and fixed-split keyboards on wrist posture and movements during word processing. The second was to select optimal computer input devices in order to prevent cummulative trauma disorder in the wrist region. The group of subjects consisted of thirteen healthy men and women who all agreed to participate in this study. Kinematic data was measured from both wrist flexion and extension, and wrist radial and ulnar deviation during a 20 minute period of word processing work. The measuring tool was an electrical goniometer, and was produced by Biometrics Cooperation. The results were as follows: 1. The wrist flexion and extension at resting starting position were not significantly different (p>.05), however the angle of radial and ulnar deviation were significantly different in standard and split keyboard use during word processing (p<.05). 2. In the initial 10 minutes, the dynamic angle of wrist flexion and extension were not significantly different (p>.05), however the dynamic angle of radial and ulnar deviation was significantly different in standard and split keyboard use during word processing (p<.05). These results suggest that the split keyboard is more optimal than the standard keyboard, because it prevented excessive ulnar deviation during word processing.