Yoo Won-gyu, Yi Chung-hwi, Kim Min-hee
Department of Rehabilitation Therapy, The Graduate School, Yonsei University, Republic of Korea.
Work. 2007;29(3):239-44.
This study examined the effect of a ball-backrest chair on the weakness and tightness of muscles associated with upper crossed syndrome when working at a visual display terminal (VDT). The surface electromyography (EMG) was recorded from the serratus anterior, middle trapezius, and upper trapezius muscles of 20 adults as they performed VDT work, which are known as the weakened and tightened muscles of upper crossed syndrome. The recorded signals were averaged and normalized to the mean amplitude of the EMG signal obtained during submaximal reference voluntary contractions. The significance of differences between the use of a general-purpose backrest and a ball backrest was tested by paired t-test, with the significance cutoff set at alpha=0.05. The activities of the serratus anterior and middle trapezius muscles increased and that of the upper trapezius muscle decreased when sitting in a ball-backrest chair compared to when sitting in a chair with a general-purpose backrest (p<0.05). These results indicate that the use of a ball-backrest chair reduces the risk of patients with upper crossed syndrome developing muscles soreness or injury related to overuse when working at a VDT.
本研究考察了在视觉显示终端（VDT）工作时，球形靠背椅对与上交叉综合征相关的肌肉无力和紧张的影响。对20名成年人在进行VDT工作时，从其前锯肌、斜方肌中束和斜方肌上束记录表面肌电图（EMG），这些肌肉是上交叉综合征中已知的无力和紧张的肌肉。记录的信号进行平均，并根据次最大参考自主收缩期间获得的EMG信号的平均幅度进行归一化。通过配对t检验来检验使用通用靠背和球形靠背之间差异的显著性，显著性临界值设定为α=0.05。与坐在通用靠背椅上相比，坐在球形靠背椅上时，前锯肌和斜方肌中束的活动增加，而斜方肌上束的活动减少（p<0.05）。这些结果表明，使用球形靠背椅可降低上交叉综合征患者在VDT工作时出现与过度使用相关的肌肉酸痛或损伤的风险。
