Changes in the Linear Relationship between Muscle Contraction Intensity and Muscle Hardness after Rectus Femoris Muscle Strain

Figure 1

(a) An MR T1 image of the rectus femoris muscle. (b) The aspect of the rectus femoris muscle during rest and contraction. (c) Strain elastographic images in healthy and rehabilitated legs related to isometric contraction intensity (10%, 20%, 30%, and 40% of maximal voluntary isometric contraction) from one subject. The strain ratios are shown by two yellow rectangular boxes, with the upper box showing the reference and the lower box showing the muscle that is the region of interest. The strain ratio has been calculated using the built-in software. The color in the region of interest (square) changes from yellow/green to blue.