Question

The amplitude of EMG signals depend upon which of the following factor?

• A. \( \text{Respiration} \)
• B. \( \text{Position of electrode} \)
• C. \( \text{Blood Resistivity} \)
• D. \( \text{Ventricular Volume} \)

Hint:

The amplitude of an EMG signal is highly sensitive to the position and contact quality} of the electrodes. Always ensure proper skin preparation and alignment with muscle fibers for accurate readings.

Answer 1

The Correct Option is B

Electromyography (EMG) records the electrical activity produced by skeletal muscles. The amplitude of EMG signals is influenced primarily by how and where the signals are recorded.

• Respiration: While muscles are involved in breathing, respiration does not directly influence the amplitude of EMG signals across all muscles.
• Position of electrode: This is a key factor. Electrodes placed close to active muscle fibers and aligned properly with them will record higher amplitude signals. Misplacement or poor contact reduces amplitude significantly.
• Blood Resistivity: Although it affects signal conduction, it is relatively stable and not a major determinant of EMG amplitude.
• Ventricular Volume: Related to cardiac function, not skeletal muscle EMG.

Hence, the correct answer is the position of the electrode.