What is the technique called that measures electrical activity of muscles using surface electrodes?

• A. Electrocardiography
• B. Electromyography (EMG)
• C. Electroencephalography
• D. Magnetoencephalography

Answer: (B)

Measuring the electrical activity of muscles with surface electrodes is electromyography, EMG. Surface EMG places electrodes on the skin over a muscle or group of muscles to pick up voltage changes generated as motor units activate and the muscle contracts. The resulting signal reflects when the muscle is activated and how strongly it is recruited, which is useful for studying movement, fatigue, and neuromuscular health. This is distinct from other techniques: electrocardiography measures the heart’s electrical activity, electroencephalography looks at brain activity, and magnetoencephalography detects magnetic fields from neural activity in the brain.