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DOI: 10.1055/s-0040-1709549
Early Functional and Morphological Changes of Calf Muscles in Delayed Onset Muscle Soreness Assessed with 7-T MRI
Publication History
Publication Date:
25 March 2020 (online)
Introduction Our objective was to assess the morphological and functional alterations of skeletal muscle after induction of delayed onset muscle soreness (DOMS) using 7-T magnetic resonance imaging (MRI).
Material and Methods DOMS was induced in 16 participants performing an eccentric exercise protocol of the calf muscles of one randomized leg. A 7-T MRI scan including two-dimensional (2D) T1-weighted (0.18 × 0.18 × 1 mm3), 2D T2-weighted sequences (0.2 × 0.2 × 2 mm3), T2 mapping (0.5 × 0.5 × 5 mm3), and three-dimensional quantitative susceptibility mapping (QSM; 0.7 × 0.7 × 0.7 mm3) was acquired at baseline (before the exercise), directly (t1), and 60 hours (t2) after the exercise. T2 signal intensity (SI), T2 values (ms), T1 SI, and QSM (ppb) were assessed in the medial gastrocnemius (MG) and lateral gastrocnemius (LG) muscle, in the soleus muscle (SM), and in the tibialis anterior muscle (AM). In addition, creatine kinase (CK) activity, extension range of motion (ROM) of the ankle joint, calf circumference, and muscle soreness were assessed at each time point.
Results Directly after exercise (t1), T2 SI (p = 0.03) and T2 values (p = 0.03) had increased significantly in the LG, which correlated with the amount of intramuscular edema and muscle soreness after 60 hours (t2) (r = 0.51, p = 0.007; r = 0.54, p = 0.005, respectively). At t1, there were no changes of SI for MG, SM, and AM. At t2, T2 SI and T2 values of LG (p = 0.001, p = 0.02) and MG (p = 0.04, p = 0.03) had increased significantly compared with baseline. T1 SI and susceptibility did not change in any muscle at any time point. Clinical parameters confirmed the induction of DOMS in every participant with a significant increase of CK (p = 0.02), muscle soreness (p < 0.001), calf circumference (p = 0.001), respectively, with a decrease of ROM (p = 0.04).
Conclusion A 7-T MRI scan allows the visualization of DOMS directly after inducing exercise and shows associations with structural and clinical manifestations 60 hours later. In contrast, expected changes in susceptibility (e.g., reflecting subclinical microhemorrhage) could not be detected with QSM.
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No conflict of interest has been declared by the author(s).