Quantitative elastosonography of the myotendinous junction: normal elastosonographic behavior and correlation with a standard measurement system during functional tests

Introduction: In recent years an increasing need to use imaging to assess normal and adaptive muscle function – besides its anatomy and structure – has emerged. We will evaluate the myotendinous junction’s elastosonography behavior in the light of the most recent literature on its physiology. The elastosonographic study is compared to the results obtained from a standard measurement system in order to ensure a correlation with maximal muscle contraction. Materials and Methods: Nineteen male professional soccer players, aged between 19 and 34 (mean age 28) were assessed during functional tests. Subjects performed, respectively, five repetitions at 60°/sec to assess muscle strength and three repetitions at 30°/sec to assess the maximum force peak of thigh muscles. Subjects were monitored by a CYBEX Isokinetic System and an ultrasound machine equipped with multi- frequency (18–6 MHz) linear array probes. Results: The results of the elastosonography study showed for the right rectus femoris an elasticity value of 30.75% with muscle relaxed and an elasticity value of 13.75% during contraction (mean decrease 17%). Elasticity values were 36.48% before contraction and 8.77% during contraction of the left rectus femoris muscle (mean decrease 27.71%).Correlation with the standard measurement system showed, for 30° eccentric contraction of the left leg, Pearson’s r-values of −0.53 and −0.51 when comparing, respectively, 38 force peak and mean work to elasticity values. 39 Discussion and Conclusion: Our study shows that strain elastosonography quantification of muscle elasticity seems to match the expected physiologic and biomechanical behavior of the myotendinous junction.