Wong T F Y, Chow D H K, Holmes A D, Cheung K M C
Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Ergonomics. 2006 Jul 15;49(9):860-73. doi: 10.1080/00140130600577460.
Poor posture has been suggested as one of the main factors contributing to the high prevalence of neck pain in video display unit (VDU) users, but no clear association between pain and any particular resting neck posture has been found. Postural awareness of the neck, as indicated by the repositioning accuracy, may therefore be an appropriate measure and potentially useful assessment tool. The objective of this study is to examine whether posture and fatigue affect the head repositioning ability in typical VDU usage. A group of 20 healthy participants reproduced a normal comfortable posture for forward, upright and backward chair back inclinations in random order both before and after fatigue of the upper trapezius muscles. Ten repetitions of the posture were recorded for 2 s each, and the angular and translational deviations from the original head position were measured with regard to the external environment (head in space repositioning) and with regard to the trunk (head on trunk repositioning). Analysis by repeated measures ANOVA showed significant effects and interactions of fatigue and chair back inclination on the repositioning errors in the sagittal plane, which typically showed systematic trends towards certain postures rather than random errors around a mean position. While further work is required to examine the ergonomic impact of impaired repositioning ability, head repositioning is sensitive to ergonomic factors such as seating configuration and fatigue, and may therefore be a useful tool for evaluation of static working postures.
不良姿势被认为是导致视频显示终端（VDU）使用者颈部疼痛高发的主要因素之一，但尚未发现疼痛与任何特定的颈部休息姿势之间存在明确关联。因此，以重新定位准确性表示的颈部姿势意识可能是一种合适的测量方法和潜在有用的评估工具。本研究的目的是检查姿势和疲劳是否会影响典型VDU使用中的头部重新定位能力。一组20名健康参与者在斜方肌上部疲劳前后，以随机顺序重现了向前、直立和向后的椅背倾斜度的正常舒适姿势。每个姿势记录10次重复，每次2秒，并测量相对于外部环境（头部在空间中的重新定位）和相对于躯干（头部在躯干上的重新定位）与原始头部位置的角度和平移偏差。重复测量方差分析表明，疲劳和椅背倾斜度对矢状面的重新定位误差有显著影响和相互作用，矢状面的重新定位误差通常显示出朝向某些姿势的系统趋势，而不是围绕平均位置的随机误差。虽然需要进一步研究来检查重新定位能力受损的人体工程学影响，但头部重新定位对座椅配置和疲劳等人因因素敏感，因此可能是评估静态工作姿势的有用工具。
