A New Tissue Hardness Meter and Algometer; a New Meter Incorporating the Functions of a Tissue Hardness Meter and an Algometer

[Purpose] The purpose of our study was to examine the reliability of a dual algometer and tissue hardness meter. [Subjects] Fourteen female American college students were used as test subjects for the tissue hardness meter, and 15 healthy Japanese adult males were used to test the algometer. All provided their informed consent. [Methods] Hardness of the rectus femoris muscle tissue was measured. Each subject sat in a resting position, with the knee bent at 60 degrees. The chair was fitted with a torque machine. Measurements were taken 3 times under each of the following conditions: No load (no muscle contraction) 10, 20, 30, 40 and 60 lbs and maximum load. Electromyograms of the rectus femoris were recorded simultaneously. The new algometer and a commercially available algometer (J-TECH) were tested for reliability. Pain threshold and pain tolerance were measured with both meters in the test subject’s elbow joints and under the lateral epicondyle of the humerus. [Results] The correlation coefficient between tissue hardness and muscle contraction was high for each level of contraction, from no load to the maximum load of voluntary contraction; the reliability of the results was therefore high. The validity of the hardness measurement of the soft tissue for each load was also high. The reliability of both algometers was high. However, comparison of pain threshold and mean degree of tolerance revealed that the value was significantly lower with the new algometer. The new algometer was fitted with a switch for use by the test subject to end the test. The use of this switch resulted in highly accurate measurements. [Conclusion] This evaluation system will be useful in the future for providing objective evidence and making advances in rehabilitation medicine and other fields in the natural sciences.