Current Directions in Biomedical Engineering (Sep 2023)
Developing a new focal vibration and heat therapy system
Abstract
Vibrational heating therapy is a type of physical therapy that uses the application of heat and vibrations to stimulate the body’s healing process. The therapy is believed to promote circulation, reduce inflammation, and relieve muscle tension. It is often used to treat conditions such as arthritis, fibromyalgia, and sports injuries. This paper presents the design-decisions for a device treating muscle soreness and to increase muscle strength through a combination of heat and vibration therapy to the upper leg. The system comprises farinfrared heat elements for heat transfer and two types of eccentric rotating masses (ERMs) and a linear resonant actuator (LRA) to vibrate muscle tissue. It discusses heating and vibration capability and performance. To optimize the mechanical effects of vibration therapy, the device must excite the muscle with an acceleration of more than 2 g and with a bandwidth as wide as the range of the muscle natural frequencies. For testing the heating and vibrational systems, they were tested in the same device on six different subjects with ethics permission from Technical University of Hamburg to obtain accurate results. Both ERMs were driven by DC power and yielded a bandwidth of about 30 Hz with a linear progression of acceleration over frequency, while the LRA was driven by AC power and achieved a bandwidth of about 24 Hz in the form of a bell curve. Also the selected heating element provides the desired temperature between 40 ∘C to 50 ∘C. Overall, the initial technical study showed promising measurement results and a mechanical effect in using this combination of heat and vibration therapy. As an outlook, the technical design of the next version of the device will include multiple actuators around the leg to provide more acceleration and aims to combine multiple LRAs with slightly shifted natural frequencies into one actuator module to extend the bandwidth.
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