Reliability and validity of muscle activity analysis using wearable electromyographs

Area of Science:

• Biomedical Engineering
• Kinesiology
• Wearable Technology

Background:

• Surface electromyography (sEMG) is crucial for assessing muscle activity.
• Existing sEMG devices often require electrodes and can be cumbersome.
• There is a need for novel, user-friendly sEMG solutions.

Purpose of the Study:

• To develop and validate a novel electrode-less wearable surface electromyograph, termed NOK.
• To compare the reliability and validity of the NOK device against an established electromyograph (Delsys).

Main Methods:

• Twenty-three healthy university students participated.
• The NOK device, featuring a rubberized contact surface, acquired up to 10 channels of muscle waveforms.
• Isometric elbow flexion and extension contractions at 50% maximal voluntary contraction were measured using both NOK and Delsys devices.

Main Results:

• A significant moderate correlation was found between NOK and Delsys for biceps and triceps measurements.
• Both devices demonstrated strong measure-retest reliability.
• Systematic errors indicated limited agreement between the two measurement methods for elbow flexion/extension.

Conclusions:

• The NOK device exhibits high repeatability and reliability.
• It is currently unsuitable for detailed muscle activity analysis due to limited agreement.
• Its multi-channel capability suggests potential future applications in rehabilitation and sports science.