A Wireless Multi-Layered EMG/MMG/NIRS Sensor for Muscular Activity Evaluation

Area of Science:

• Biomedical Engineering
• Sports Science
• Wearable Technology

Background:

• Simultaneous measurement of muscle activity using multiple modalities is crucial for comprehensive analysis.
• Existing sensors often lack the ability to integrate electromyography (EMG), mechanomyography (MMG), and near-infrared spectroscopy (NIRS).
• Developing a single, wireless sensor for these combined measurements can enhance exercise physiology research.

Purpose of the Study:

• To present a novel wireless multi-layered sensor capable of simultaneous EMG, MMG, and NIRS measurements.
• To demonstrate the sensor's utility in analyzing muscular activity during different exercise protocols.
• To explore the potential of integrated physiological data for evaluating exercise performance.

Main Methods:

• A multi-layered sensor was designed, incorporating a silver electrode for EMG, a piezo-film for MMG, and a photosensor for NIRS.
• Simultaneous EMG, MMG, and NIRS signals were recorded from forearm and vastus lateralis muscles during isometric ramp contractions and cycling exercise.
• Data analysis focused on correlating the three signal types to assess muscular responses under varying loads.

Main Results:

• The proposed sensor successfully acquired simultaneous EMG, MMG, and NIRS data from localized muscle sites.
• Experimental trials demonstrated the feasibility of using the sensor during dynamic and isometric exercises.
• The integrated data provided a detailed view of muscular activity, though anaerobic threshold detection requires further investigation.

Conclusions:

• The developed wireless multi-layered sensor enables concurrent EMG, MMG, and NIRS measurements.
• This integrated approach shows significant potential for evaluating muscular activity and exercise responses.
• Further research is needed to refine the sensor's capabilities, particularly for identifying specific physiological markers like the anaerobic threshold.