Context: Clinicians use a number of superficial and deep heating modalities, including pulsed shortwave diathermy (PSWD) and moist hot packs, in the clinical setting. Recently, a continuous diathermy unit called ReBound was introduced into the clinical setting. Its effectiveness as a heating modality is unknown. Objective: To compare the effects of PSWD, moist hot packs and the ReBound unit on tissue temperature in the triceps surae muscle. Design: A 3 x 27 factorial cross-over design with repeated measures. Setting: University research laboratory. Subjects: Twelve healthy college-aged volunteers (4 men, 8 women; age = 22.2 ± 2.25; calf subcutaneous fat thickness = .72 cm ± .19 cm). Interventions: On three different days separated by at least 48 hours, one of three modality treatments (PSWD, moist hot packs or ReBound unit) selected using a Latin-square was applied to the triceps surae muscle of each participant for 30 minutes. After the 30 minute treatment, the modality was removed and temperature decay was recorded for 20 minutes. Main Outcome Measures: Medial triceps surae intramuscular tissue temperature at 1 cm and 3 cm deep was measured using implantable thermocouples inserted horizontally into the muscle. Measurements were taken every 5 minutes during the 30 minute treatment and every minute during the 20 minute temperature decay for a total of 50 minutes. A 3 x 27 mixed model analysis of variance blocking by subject was used to assess the effects of treatments and time, and their interaction on the tissue temperature at 1 cm and 3 cm depths. Results: A significant treatment by time interaction main effect was found for tissue temperature increase at each depth, 1 cm (F52, 572 =14.66, p < .0001) and 3 cm (F52, 572 = 17.86, p < .0001). Post-hoc measures revealed that tissue temperature significantly increased with the PSWD over the ReBound unit and moist hot packs at 1 cm and 3 cm depths. There was no significant difference between the ReBound unit and moist hot packs throughout the treatment and temperature decay. The greatest mean tissue temperature increase from baseline was observed with the PSWD unit at 1 cm (5.96°C ± 2.04°C) and at 3 cm (4.32°C ± 1.79°C). There was no statistical difference between the increases observed with the ReBound (1 cm: 3.69°C ± 1.50; 3 cm: 2.31°C ± .87) and moist hot packs (1 cm: 2.82°C ± .90; 3 cm: 1.56°C ± 1.00). Conclusions: During a 30 minute treatment, PSWD was the most effective at increasing intramuscular tissue temperature of the triceps surae muscle group. There was no significant difference between the effectiveness of moist hot packs and the ReBound continuous diathermy unit in increasing intramuscular tissue temperature.



College and Department

Life Sciences; Exercise Sciences



Date Submitted


Document Type





shortwave diathermy, continuous diathermy, intramuscular temperature, heat