Which modality is designed to produce an isometric contraction and is useful in muscle reeducation?

• A. Russian current
• B. Iontophoresis
• C. High-voltage stimulation
• D. Transcutaneous electrical nerve stimulation

Answer: (A)

The key idea is using electrical stimulation to generate a controlled muscle contraction that helps retrain motor function. The Russian current is built to produce strong, smooth tetanic contractions by delivering a medium-frequency carrier in bursts. This pattern gives a reliable and comfortable contraction that can be held at a fixed joint angle, making it ideal for muscle reeducation and strengthening without the muscle length changing—what we call an isometric contraction.

Iontophoresis uses direct current to push ions into tissues and isn’t intended to cause muscle contractions. High-voltage stimulation can induce contractions but is typically aimed at other goals like wound healing or edema reduction rather than targeted muscle reeducation. TENS focuses on pain relief and sensory modulation rather than producing purposeful muscle contractions for strengthening.