Publications
Layer-Specific Shear Wave Elastography Reveals the Tissue Origin of MyotonPRO-Derived Muscle Stiffness
Authors: Sebastian Szajkowski 1, Michal Dwornik 2, Krzysztof Suszynski 3, Jaroslaw Pasek 4
Affiliations:
- Faculty of Medical Sciences, Warsaw Medical Academy of Applied Sciences, 8 Rydygiera St., 01-793 Warszawa, Poland
- Medical Rehabilitation and Osteopathy Clinic REHApunkt, Traugutta 12 St., 05-820 Piastow, Poland
- Department of Sports Medicine and Physiology of Physical Exercise, Faculty of Health Science in Katowice, Medical University of Silesia, 40-055 Katowice, Poland
- Collegium Medicum im dr Wladyslawa Bieganskiego, Jan Dlugosz University in Czestochowa, 13/15 Armii Krajowej St., 42-200 Czestochowa, Poland
Journal: Diagnostics - August 2026, Volume 16, Issue 15, Article no. 2346 (DOI: 10.3390/diagnostics16152346)
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Field & Applications:
- Methodology
- Medical
- Musculoskeletal health
- Myofascia
- Musculoskeletal rehabilitation
- Validity
Background: Shear wave elastography (SWE) and myotonometry are commonly used to assess muscle stiffness, but they reflect different aspects of tissue mechanics. SWE allows layer-specific evaluation, whereas myotonometry captures the response of a broader tissue complex. The contribution of individual layers to MyotonPRO-derived stiffness remains unclear. This study examined the relationship between MyotonPRO stiffness and layer-specific SWE measurements in the tibialis anterior muscle.
Methods: In this cross-sectional study, 56 healthy adults were evaluated. Muscle stiffness was assessed using MyotonPRO and SWE across three regions of interest: superficial tissues including skin, subcutaneous tissue, and deep fascia (ROI 1); muscle tissue excluding fascia (ROI 2); and a composite region including all tissues from the skin surface to a depth of 2 cm (ROI 3). Relationships were analyzed using Spearman correlation, multiple linear regression, and Bland–Altman analysis.
Results: Moderate but consistent correlations were observed between MyotonPRO stiffness and SWE values in ROI 2 (ρ = 0.516, p < 0.001) and ROI 3 (ρ = 0.550, p < 0.001), whereas no significant association was found in ROI 1. SWE values in ROI 2 and ROI 3 were significant predictors of MyotonPRO stiffness, explaining 38% of the variance. Bland–Altman analysis demonstrated moderate agreement with a systematic bias toward higher MyotonPRO values.
Conclusions: MyotonPRO-derived stiffness reflects a composite mechanical response of muscle and surrounding tissues, with the strongest associations observed in regions encompassing both muscle and fascia. These findings highlight the importance of tissue composition and ROI selection in stiffness assessment and may facilitate more accurate interpretation of MyotonPRO measurements in musculoskeletal diagnostics and rehabilitation.
Keywords: shear wave elastography, MyotonPRO, muscle stiffness, elasticity imaging techniques
The present findings demonstrate that MyotonPRO-derived stiffness reflects a composite biomechanical response involving both muscle and fascial tissues rather than isolated muscle properties. The strongest associations were observed in regions encompassing muscle tissue and the muscle–fascia complex, whereas no significant relationship was identified for superficial tissues alone.
These findings emphasize the importance of tissue composition and ROI selection when interpreting stiffness measurements, indicating that MyotonPRO captures an integrated mechanical response influenced by multiple tissue layers. Consequently, MyotonPRO measurements should not be interpreted as representing isolated muscle stiffness alone.
From a diagnostic perspective, layer-specific SWE may improve understanding of the tissue structures contributing to MyotonPRO-derived stiffness and facilitate more accurate interpretation of biomechanical measurements. Combined assessment using SWE and myotonometry may provide complementary information for musculoskeletal diagnostics, rehabilitation monitoring, and future research applications.