Muscle heating with Megapulse II shortwave diathermy and ReBound diathermy.

Context: A new continuous diathermy called ReBound recently has been introduced. Its effectiveness as a heating modality is unknown.

Objective: To compare the effects of the ReBound diathermy with an established deep-heating diathermy, the Megapulse II pulsed shortwave diathermy, on tissue temperature in the human triceps surae muscle.

Design: Crossover study.

Setting: University research laboratory.

Patients Or Other Participants: Participants included 12 healthy, college-aged volunteers (4 men, 8 women; age = 22.2 ± 2.25 years, calf subcutaneous fat thickness = 7.2 ± 1.9 mm).

Intervention(s): Each modality treatment was applied to the triceps surae muscle group of each participant for 30 minutes. After 30 minutes, we removed the modality and recorded temperature decay for 20 minutes.

Main Outcome Measure(s): We horizontally inserted an implantable thermocouple into the medial triceps surae muscle to measure intramuscular tissue temperature at 3 cm deep. We measured temperature every 5 minutes during the 30-minute treatment and each minute during the 20-minute temperature decay.

Results: Tissue temperature at a depth of 3 cm increased more with Megapulse II than with ReBound diathermy over the course of the treatment (F₆,₆₆ = 10.78, P < .001). ReBound diathermy did not produce as much intramuscular heating, leading to a slower heat dissipation rate than the Megapulse II (F₂₀,₂₂₀ = 28.84, P < .001).

Conclusions: During a 30-minute treatment, the Megapulse II was more effective than ReBound diathermy at increasing deep, intramuscular tissue temperature of the triceps surae muscle group.