Schlenker Anna, Tichý Tomáš
Institute of Hygiene and Epidemiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
Department of Biomedical Informatics, Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic.
Cent Eur J Public Health. 2017 Dec;25(4):255-260. doi: 10.21101/cejph.a5105.
The aim of this study was to assess the contribution of using keystroke dynamics (KD) in combination with integrated electromyography (iEMG) for the objective evaluation of local muscular load of hands and forearms while typing on a computer keyboard and to compare it with results of the commonly used method.
Study was performed on 12 subjects. Data were collected using our own application for capturing KD data and using EMG Holter for detecting electromyographic potentials to determine local muscular load.
The results of our study revealed that currently used methods for assessment of the workload while typing on a computer keyboard are not entirely accurate. In particular, the real total number of keystrokes performed during processing of a text is significantly higher than the count of characters the text is consisting of. In addition to this count, also the so-called invisible keys, keyboard shortcuts, and especially corrections in the typed text must be taken into consideration.
The results indicated that all probands in our study exceeded the valid hygienic limits for the total amount of the small repetitive movements of the hands and forearms and the total amount of the keyboard typing movements. Most of the probands in our study also exceeded the valid hygienic limit for the highest average time-weighted value of the percent maximum voluntary contraction (%MVC). This implies that the keystroke dynamics method has a great potential to increase the accuracy of evaluation of local muscular load when using the keyboard and thus to improve the existing methodology for investigation of occupational diseases resulting from overload while working on the computer.
本研究的目的是评估结合按键动力学（KD）与集成肌电图（iEMG）对在计算机键盘上打字时手部和前臂局部肌肉负荷进行客观评估的贡献，并将其与常用方法的结果进行比较。
对12名受试者进行了研究。使用我们自己开发的用于捕获KD数据的应用程序以及用于检测肌电电位以确定局部肌肉负荷的肌电图动态监测仪来收集数据。
我们的研究结果表明，目前用于评估在计算机键盘上打字时工作量的方法并不完全准确。特别是，在处理文本过程中实际执行的按键总数明显高于文本所包含的字符数。除了这个计数外，还必须考虑所谓的隐形键、键盘快捷键，尤其是输入文本中的修正。
结果表明，我们研究中的所有受试者手部和前臂的小重复动作总量以及键盘打字动作总量均超过了有效的卫生限值。我们研究中的大多数受试者还超过了最大自主收缩百分比（%MVC）的最高平均时间加权值的有效卫生限值。这意味着按键动力学方法在使用键盘时具有提高局部肌肉负荷评估准确性的巨大潜力，从而改进现有的因计算机工作过载导致的职业病调查方法。
