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名稱 |
Electromyographical Assessment on Muscular Fatigue in Ergonomic Studies – A demonstration from repetitive Typing Activities |
類型 |
會議論文 |
年份 |
2003 |
著作人 |
Ming-Yi Lin;Hui-Wen Liang;Yaw-Huei Hwang |
摘要 |
The main objectives of this study were to observe the alternations of muscle function resulting from the influence of high repetitive muscular activities and to verify the applicability of surface electromyogram (EMG) in characterizing low-force dynamics contractions. Therefore, an electromyographical fatigue analysis was performed in the long-term rapid typing experiment. Thirty ubjects were recruited to type for 2 hours. The muscular activity of muscle extensor digitorum communis (EDC) and muscle flexor digitorum superficialis (FDS) of both hands were recorded throughout the entire experiment. The electrical activity (EA) and median frequency (MDF) were calculated, then regressed against the time courses of these parameters. The revised method of joint analysis of spectra and amplitudes of EMG (JASA) was introduced in this study and used to demodulate the EMG registrations into individual level. The results demonstrated a decreasing trend in the time series of frequency parameters throughout the entire trial and MDF values reduced by 25% comparing to the initial values obtained at the beginning of typing activities. Furthermore, 80% muscles manifested fatigue through the JASA method after the 2-hour typing experiment. Results of the present study support the use of MDF values derived from surface EMG signals recorded during dynamic contractions to quantify fatigue of the EDC and FDS muscles, even at the low exerting force level (2% MVC). Moreover, the JASA method allows investigators to infer reasonable representations. |
關鍵字 |
ergonomics;electromyogram;dynamic contractions;muscle fatigue;typing |
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