Justin H. Rigby

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.

Heating capacity of rebound shortwave diathermy and moist hot packs at superficial depths.

CONTEXT The effectiveness of a new continuous diathermy unit, ReBound, as a heating modality is unknown. OBJECTIVE To compare the effects of ReBound diathermy with silicate-gel moist hot packs on tissue temperature in the human triceps surae muscle. DESIGN Crossover study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 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) On 2 different days, 1 of 2 modalities (ReBound diathermy, silicate-gel moist hot pack) was applied to the triceps surae muscle of each participant for 30 minutes. After 30 minutes, the modality was removed, and temperature decay was recorded for 20 minutes. MAIN OUTCOME MEASURE(S) Medial triceps surae intramuscular tissue temperature at a depth of 1 cm was measured using an implantable thermocouple 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. Treatment was analyzed through a 2 × 7 mixed-model analysis of variance with repeated measures. Temperature decay was analyzed through a 2 × 21 mixed-model analysis of variance with repeated measures. RESULTS During the 30-minute application, tissue temperatures at a depth of 1 cm increased more with the ReBound diathermy than with the moist hot pack (F6,66 = 7.14, P < .001). ReBound diathermy and moist hot packs increased tissue temperatures 3.69°C ± 1.50°C and 2.82°C ± 0.90°C, respectively, from baseline. Throughout the temperature decay, ReBound diathermy produced a greater rate of heat dissipation than the moist hot pack (F20,222 = 4.42, P < .001). CONCLUSIONS During a 30-minute treatment at a superficial depth, the ReBound diathermy increased tissue temperature to moderate levels, which were greater than the levels reached with moist hot packs.

The Time Course of Dexamethasone Delivery Using Iontophoresis Through Human Skin, Measured via Microdialysis

STUDY DESIGN Controlled laboratory study. OBJECTIVE To determine the time course of dexamethasone sodium phosphate (Dex-P) during iontophoresis to underlying tissues using microdialysis. BACKGROUND In human participants, real-time information of Dex-P transdermal delivery during iontophoresis is unknown. METHODS Sixty-four healthy male participants (mean ± SD age, 24.2 ± 3.3 years; height, 181.8 ± 26.1 cm; mass, 82.4 ± 11.8 kg; subcutaneous fat thickness, 0.61 ± 0.19 cm) were randomly assigned into 1 of 6 groups: (1) 1-mA current, 1-mm probe depth; (2) 1-mA current, 4-mm probe depth; (3) 2-mA current, 1-mm probe depth; (4) 2-mA current, 4-mm probe depth; (5) in vivo retrodialysis; and (6) skin perfusion flowmetry. Microdialysis probes were used to assess the combined recovery (Dex-total) of Dex-P, dexamethasone, and its metabolite. RESULTS There was no difference in Dex-total between current intensities (P = .99), but a greater amount of Dex-total was recovered superficially at 1 mm compared to the 4-mm depth (P<.0001). Peak concentration mean ± SD values for the 1- and 2-mA currents at 1 mm were 10.8 ± 8.1 and 7.7 ± 5.5 µg/mL, and at 4 mm were 2.0 ± 0.8 and 1.3 ± 0.9 µg/mL, respectively. Peak skin perfusion was 741.4% ± 408.7% and 711.6% ± 260.8% at baseline for 1- and 2-mA intensities, respectively. Skin perfusion returned to baseline levels earlier during 1-mA intensity at a 110 mA · min dose within the treatment, compared to 2 mA at 60 minutes posttreatment. CONCLUSION Transdermal delivery of Dex-P during iontophoresis was successfully measured in vivo through human skin. Measurable concentrations of Dex-total were found regardless of current intensity. Although current-induced vasodilation occurred, it did not significantly affect the tissue accumulation of Dex-total.

Effects of Long Duration Low Intensity Ultrasound for Active Trapezius Trigger Points: A Randomized Clinical Trial

CONTEXT Upper trapezius trigger points can be debilitating and often lead to chronic pain. OBJECTIVE To determine if long duration low intensity therapeutic ultrasound is effective at treating upper trapezius trigger point pain compared to an inactive placebo treatment. DESIGN Randomized control trial. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Fifty-one participants (19 males, 32 females, age = 31.8 ± 12.5 y, ht = 168.6 ± 15.9 cm, mass = 77.1 ± 16.1 kg) diagnosed with chronic upper trapezius pain. INTERVENTIONS Participants were randomly assigned into an active (n = 32) or sham (n = 19) treatment group. Treatments were applied at least 3 times a week for 4 weeks and each ultrasound treatment lasted 4 h. MAIN OUTCOME MEASURES Participants completed a daily numeric rating scale (NRS) pain diary. Pain pressure threshold was assessed via a pressure algometer. Repeated-measures ANCOVAs were used to examine differences over time and between groups. RESULTS Pain on the NRS was significantly reduced from baseline (5.4 ± 1.7) to the conclusion of the study (4.2 ± 1.6) (F4,254 = 7.747, P < 0.001); however, the reduction did not significantly differ between the two groups (F4,254 = 1.096, P = 0.359). There was an average reduction in pain of 1.1 ± 1.8 points over the course of a 4 h treatment (F4,254 = 18.67, P = 0.001), but this reduction did not differ between groups, (F4,254 = 0.701, P = 0.592). Pain pressure threshold improved by 0.46 ± 1.29 and 0.44 ± 1.73 kg for active and sham groups, respectively, but was not different between groups (F2,142 = 1.168, P = 0.314). CONCLUSIONS Four-weeks of low intensity long duration ultrasound reduced upper trapezius trigger point pain, but the improvement is attributed to a placebo effect.

Effectiveness of Various Cryotherapy Systems at Decreasing Ankle Skin Temperatures and Applying Compression

A variety of cryotherapy systems may be used to cool tissues immediately after an injury. The purpose our study was to examine the effect of a 30-min application of various cryotherapy devices on skin temperatures and compression. A crossover-designed study performed in a university research laboratory was conducted. Each treatment condition was applied to the lateral ankle for 30 min on different days. HyperIce’s colder temperatures over the lateral ankle (p < .0001) would make it the treatment choice for immediate care of ankle lateral ligament injuries, but is limited due its size for larger injuries.

Intramuscular Heating Characteristics of Multihour Low-Intensity Therapeutic Ultrasound

CONTEXT The heating characteristics of a stationary device delivering sustained acoustic medicine with low-intensity therapeutic ultrasound (LITUS) are unknown. OBJECTIVE To measure intramuscular (IM) heating produced by a LITUS device developed for long-duration treatment of musculoskeletal injuries. DESIGN Controlled laboratory study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 26 healthy volunteers (16 men, 10 women; age = 23.0 ± 2.1 years, height = 1.74 ± 0.09 m, mass = 73.48 ± 14.65 kg). INTERVENTION(S) Participants were assigned randomly to receive active (n = 20) or placebo (n = 6) LITUS at a frequency of 3 MHz and an energy intensity of 0.132 W/cm(2) continuously for 3 hours with a single transducer or dual transducers on the triceps surae muscle. We measured IM temperature using thermocouples inserted at 1.5- and 3-cm depths into muscle. Temperatures were recorded throughout treatment and 30 minutes posttreatment. MAIN OUTCOME MEASURE(S) We used 2-sample t tests to determine the heating curve of the LITUS treatment and differences in final temperatures between depth and number of transducers. RESULTS A mild IM temperature increase of 1 °C was reached 10 ± 5 minutes into the treatment, and a more vigorous temperature increase of 4 °C was reached 80 ± 10 minutes into the treatment. The maximal steady-state IM temperatures produced during the final 60 minutes of treatment at the 1.5-cm depth were 4.42 °C ± 0.08 °C and 3.92 °C ± 0.06 °C using 1 and 2 transducers, respectively. At the 3.0-cm depth, the maximal steady-state IM temperatures during the final 60 minutes of treatment were 3.05 °C ± 0.09 °C and 3.17 °C ± 0.05 °C using 1 and 2 transducers, respectively. We observed a difference between the temperatures measured at each depth (t78 = -2.45, P = .02), but the number of transducers used to generate heating was not different (t78 = 1.79, P = .08). CONCLUSIONS The LITUS device elicited tissue heating equivalent to traditional ultrasound but could be sustained for multiple hours. It is a safe and effective alternative tool for delivering therapeutic ultrasound and exploring dosimetry for desired physiologic responses.

Difference in Tissue Temperature After Therapeutic Ultrasound Using Biofreeze Mixture and Ultrasound Gel as Coupling Media

Biofreeze, a topical analgesic, is commonly used as a coupling medium during therapeutic ultrasound to add greater relief of pain, although it may block transmission of ultrasound energy. Our objective was to compare a mixture of 1-part Biofreeze and 3-parts ultrasound gel to 100% ultrasound gel to assess intramuscular heating and perceived sensation of heat. Fifteen participants received a continuous 3-MHz ultrasound treatment with the Biofreeze mixture or 100% ultrasound gel on 2 diff erent days. We measured intramuscular tissue temperature and visual analog scale scores for heat sensation. The Biofreeze mixture produced a tissue temperature increase similar to the 100% ultrasound gel (P = .32), while producing a greater perceived sensation of heat (P � .0001). However, due to Biofreeze’s viscosity, more of the mixture (12.9 � 2.6 mL) was needed than the ultrasound gel (10 � 0 mL) to prevent overheating of superfi cial tissues. [Athletic Training & Sports Health Care. 2013;5(x):xxx-xxx.]