How should electrodes be aligned relative to the muscle?

• A. Parallel
• B. Perpendicular
• C. Diagonal
• D. Circular

Answer: (A)

In NMES, electrode orientation matters because the electrical field should run along the muscle fibers to recruit motor units efficiently. When the electrodes are placed parallel to the direction of the muscle fibers, the current travels along the length of the muscle, allowing deeper, more uniform activation of the motor units and producing a stronger, steadier contraction with usually less skin discomfort. Placing electrodes perpendicular often targets superficial fibers and can lead to less effective recruitment and more localized sensation. Diagonal or circular placements don’t align with the fiber direction, which makes the stimulation less predictable and efficient. So, you want the electrodes aligned parallel to the muscle fibers. For example, on a biceps, position them along the long axis of the muscle.