Force Sensing for an Instrument-Assisted Soft Tissue Manipulation Device

Abstract

Instrument-assisted soft tissue manipulation (IASTM) is a form of mechanotherapy, e.g., massage, that uses rigid devices which may be machined or cast. The delivered force, which is a critical parameter during IASTM, is not measured and not standardized in current clinical IASTM practice. In addition to the force, the angle of treatment and stroke frequency play an important role during IASTM. For accurate IASTM treatment, there is a strong need to scientifically characterize the IASTM delivered force, angle of treatment, and stroke frequency. This paper presents a novel, mechatronic design of an IASTM device that can measure the localized pressure on the soft tissue in a clinical treatment. The proposed design uses a three-dimensional (3D) load cell, which can measure all three-dimensional force components simultaneously. The device design was implemented using an IMUduino microcontroller board which provides tool orientation angles. These orientation angles were used for coordinate transformation of the measured forces to the tool–skin interface. Additionally, the measured force value was used to compute the stroke frequency. This mechatronic IASTM tool was validated for force measurements in the direction of tool longitudinal axis using an electronic plate scale that provided the baseline force values to compare with the applied force values measured by the tool. The load cell measurements and the scale readings were found to agree within the expected degree of accuracy.