Quantitative Elastosonography of the Myotendinous Junction: Normal Behavior and Correlation With a Standard Measurement System During Functional Tests

Objectives-In recent years, an increasing need to use imaging to assess normal and adaptive muscle function, in addition to its anatomy and structure, has emerged. We evaluated the myotendinous junction's elastosonographic behavior in light of the most recent literature on its physiologic behavior. The elastosonographic studies were compared with the results obtained from a standard measurement system to ensure a correlation with maximal muscle contraction. Methods-Nineteen male professional soccer players were assessed during functional tests. The participants performed 5 repetitions at 608/s to assess muscle strength and 3 repetitions at 308/s to assess the maximum force peak of thigh muscles. The participants were monitored by a strength-power measurement system and an ultrasound machine equipped with multifrequency (18-6-MHz) linear array transducers. Results-The 19 soccer players were aged between 19 and 34 years (mean age, 28 years). For the right rectus femoris, the results of the elastosonographic studies showed a mean elasticity value 6 SD of 30.75% 6 10.05% with the muscle relaxed and a value of 13.75% 6 8.44% during contraction (mean decrease, 17.00% 6 11.71%). Elasticity values were 36.48% 6 8.39% before contraction and 8.77% 6 6.55% during contraction of the left rectus femoris muscle (mean decrease, 27.71% 6 11.95%). For 308 eccentric contraction of the left leg, correlation with the standard measurement system showed Pearson r values of 20.53 and 20.51 when comparing force peak and mean work, respectively, with elasticity values. Conclusions-Our study shows that strain elastosonographic quantification of muscle elasticity seems to match the expected physiologic and biomechanical behavior of the myotendinous junction.