Publications

• Employing this multi-point protocol enhances the spatial resolution of myotonometric measurements and minimizes the subjectivity associated with manual palpation-based assessments.
• The results from the protocol’s application describe the biomechanical and viscoelastic variables of myotonometry and demonstrate statistically significant variations in stiffness (N/m) with large effect sizes, reinforcing its relevance in biomechanics, clinical assessments, and rehabilitation research.

The assessment of biomechanical and viscoelastic properties of superficial tissues using myotonometry has gained prominence in clinical and research settings due to its ease of use and ability to provide objective measurements. However, there is a tendency to assess only a single point without considering anatomical or functional variations, and its representativeness for broad regions, such as the lower limbs, remains uncertain. Consequently, we aimed to develop a standardized multi-point protocol for evaluating biomechanical and viscoelastic properties in the lower limbs using myotonometry, test its feasibility and discriminative capacity, and present preliminary exploratory findings.

A multi-point myotonometric assessment protocol was developed, where thirty-eight assessment points were identified and described for evaluating the anterior, lateral, posterior, and inferior compartments of the lower limbs. The protocol was applied to both limbs of 13 healthy adult males (age: 32.15 ± 6.50 years). Values were described using mean and standard deviation, and comparisons between consecutive points were tested using the Wilcoxon signed-rank test. Effect sizes were calculated as r = Z/√N. IBM® SPSS Statistics 20.0 was used with a significant level of 5%.

Stiffness values (N/m) showed statistically significant variations between consecutive points, ranging from 136.87 N/m (± 25.55) to 1118.28 N/m (± 357.84), with effect sizes ranging from r = 0.595 to r = 0.874. The statistically significant increase in the proximal-distal and medio-lateral directions, with progressively higher values in the distal and lateral regions, indicates a directional behavior of this property.

The proposed multi-point methodology represents an advancement in non-invasive biomechanical assessment. As a methodological development study with preliminary findings, the protocol demonstrates capacity to detect location-dependent variations in stiffness with large effect sizes. Following validation in larger, diverse cohorts, it offers potential for improving diagnosis, therapeutic monitoring, and understanding tissue adaptation mechanisms in clinical and functional contexts.

Trial registration: CEPSH/UDESC (CAAE 65601722.5.0000.0118)

Keywords: soft tisuse, connective tisuse, muscle, fascia, myotonometry, MyotonPRO, anthropometry, stiffness.

This study developed and implemented a new methodological approach for myotonometry assessments, utilizing multiple standardized assessment points in the lower limbs, based on individual anatomical normalization. As a methodological development study with preliminary exploratory findings, the primary contribution is the standardized protocol itself, which addresses significant gaps in current myotonometry practice. This approach enables a more comprehensive and systematic evaluation of tissue properties, addressing limitations in previous protocols that relied on single-point assessments.

The results describe the biomechanical and viscoelastic variables of myotonometry and demonstrate statistically significant variations in stiffness (N/m) throughout the lower limb, revealing specific distribution patterns and tissue behavior. Stiffness values progressively increased in the distal and lateral directions across most evaluated structures. These findings emphasize the importance of standardizing assessment points in myotonometry protocols, given the locational dependence of biomechanical properties. Thus, the proposed protocol represents a significant advancement in non-invasive biomechanical assessment, offering potential for enhanced diagnostic accuracy, improved therapeutic monitoring, and a deeper understanding of tissue adaptation mechanisms across diverse clinical and functional contexts.

While the small sample size (n=13 independent participants) and homogeneous composition limit immediate clinical application and generalizability, the preliminary findings demonstrate the protocol’s capacity to detect systematic, location-dependent variations in tissue stiffness with large effect sizes. These hypothesis-generating results provide foundation for future adequately powered investigations across diverse populations and clinical conditions. Validation studies employing multilevel analytical frameworks, larger samples, and integration with imaging modalities will be essential for establishing normative reference values, clinical thresholds, and diagnostic utility. The standardized protocol developed herein provides the methodological foundation for such investigations, representing a significant advancement in non-invasive biomechanical assessment methodology.