Assessment of the elasticity value using a soft tissue stiffness meter

[Purpose] The purpose of this study was to investigate a method for assessing elasticity values by analyzing the relationship between muscle contraction strength and the hardness of soft tissue (STS) at different joint angles. [Subjects] The subjects were 20 healthy young men. [Method] To determine the relationship between degree of muscle contraction and STS, we measured STS of the quadriceps femoris (QF) at 0, 25, 50, 75 and 100% of maximum contraction with the knee flexed at 90° using a STS meter and isometric muscle strength measuring equipment. For the relationship between joint angle and STS, we measured STS from 0 ° of knee extension to maximum flexion in the supine position using a STS meter and an electronic goniometer. STS was measured in the center of the QF with the thigh and lower leg held by a sling in the lateral position at a load of 10 N. The analysis of differences in STS at different joint angles and muscle contraction strengths was performed using multiple comparisons and repeated measures one-way analysis of variance. [Results] Significant decreases in elasticity value were found between all values of muscle contraction and at angles of flexion greater than 90 °. [Conclusion] We consider that measurements of STS during muscle contraction are an index showing pressure changes in the muscle, and measurements of STS at different joint angles are an index of extensibility.