Which modality is associated with muscle strengthening?

• A. Medium frequency Russian
• B. Shortwave diathermy
• C. High-frequency TENS
• D. Cryotherapy

Answer: (A)

Muscle strengthening comes from producing controlled muscle contractions that provide a training stimulus to the muscle. The medium-frequency Russian current is designed for this purpose: it delivers electrical stimulation that reliably elicits strong, tetanic contractions in the targeted muscle, which helps rebuild strength and improve neural activation, especially when voluntary contractions are limited after injury or atrophy. By contrast, shortwave diathermy focuses on heating tissues for pain relief and tissue extensibility; high-frequency TENS targets pain modulation rather than muscle strengthening; and cryotherapy is used to reduce inflammation and soreness rather than to strengthen muscle. So the modality that best supports strengthening is the medium-frequency Russian current because it directly drives the muscle to contract and adapt.