What is the Russian current and what setting does it use?

• A. A direct current with fixed amplitude.
• B. An alternating current at 60 Hz used for pain modulation.
• C. A medium-frequency carrier around 2,500 Hz modulated to produce low-frequency bursts (about 50 Hz) for muscle strengthening with short on/off intervals.
• D. A high-frequency continuous waveform used for heating.

Answer: (C)

The Russian current works by using a medium-frequency carrier that is modulated to produce low-frequency bursts. Specifically, about a 2,500 Hz alternating current is delivered, but it’s not continuous. It’s turned on and off in bursts that create an effective stimulation around 50 Hz. This combination lets the muscle receive a strong, tetanic contraction while skin impedance and discomfort are minimized because the high-frequency carrier travels more easily through tissue. The short on/off intervals provide repeated contractions with brief rests, which is ideal for muscle strengthening.

This is different from a direct current, which would be a steady flow with a single polarity; or from a simple 60 Hz alternating current used primarily for pain modulation; or from a high-frequency continuous waveform used for heating (diathermy). The defining setup for the Russian current is the 2,500 Hz carrier modulated to low-frequency bursts near 50 Hz for strengthening.