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An EMG Patch for the Real-Time Monitoring of Muscle-Fatigue Conditions During Exercise

Department of Computer Science and Information Engineering, Chaoyang University of Technology, Taichung City 41349, Taiwan
Department of Information and Communication Engineering, Chaoyang University of Technology, Taichung City 41349, Taiwan
Biomedical Information Engineering Laboratory, University of Aizu, Aizu-wakamatsu City, Fukushima 965-8580, Japan
Department of Industrial Design, Chaoyang University of Technology, Taichung City 41349, Taiwan
Department of Leisure Services Management, Chaoyang University of Technology, Taichung City 41349, Taiwan
Author to whom correspondence should be addressed.
Sensors 2019, 19(14), 3108;
Received: 21 May 2019 / Revised: 7 July 2019 / Accepted: 12 July 2019 / Published: 14 July 2019
(This article belongs to the Special Issue Wearable Wireless Sensors)
PDF [5166 KB, uploaded 14 July 2019]
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In recent years, wearable monitoring devices have been very popular in the health care field and are being used to avoid sport injuries during exercise. They are usually worn on the wrist, the same as sport watches, or on the chest, like an electrocardiogram patch. Common functions of these wearable devices are that they use real time to display the state of health of the body, and they are all small sized. The electromyogram (EMG) signal is usually used to show muscle activity. Thus, the EMG signal could be used to determine the muscle-fatigue conditions. In this study, the goal is to develop an EMG patch which could be worn on the lower leg, the gastrocnemius muscle, to detect real-time muscle fatigue while exercising. A micro controller unit (MCU) in the EMG patch is part of an ARM Cortex-M4 processor, which is used to measure the median frequency (MF) of an EMG signal in real time. When the muscle starts showing tiredness, the median frequency will shift to a low frequency. In order to delete the noise of the isotonic EMG signal, the EMG patch has to run the empirical mode decomposition algorithm. A two-electrode circuit was designed to measure the EMG signal. The maximum power consumption of the EMG patch was about 39.5 mAh. In order to verify that the real-time MF values measured by the EMG patch were close to the off-line MF values measured by the computer system, we used the root-mean-square value to estimate the difference in the real-time MF values and the off-line MF values. There were 20 participants that rode an exercise bicycle at different speeds. Their EMG signals were recorded with an EMG patch and a physiological measurement system at the same time. Every participant rode the exercise bicycle twice. The averaged root-mean-square values were 2.86 ± 0.86 Hz and 2.56 ± 0.47 Hz for the first and second time, respectively. Moreover, we also developed an application program implemented on a smart phone to display the participants’ muscle-fatigue conditions and information while exercising. Therefore, the EMG patch designed in this study could monitor the muscle-fatigue conditions to avoid sport injuries while exercising. View Full-Text
Keywords: electromyogram; patch; muscle fatigue; application program electromyogram; patch; muscle fatigue; application program

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Liu, S.-H.; Lin, C.-B.; Chen, Y.; Chen, W.; Huang, T.-S.; Hsu, C.-Y. An EMG Patch for the Real-Time Monitoring of Muscle-Fatigue Conditions During Exercise. Sensors 2019, 19, 3108.

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