A microstructurally-based, multi-scale, continuum-mechanical model for the passive behaviour of skeletal muscle...

Area of Science:

• Biomechanics
• Materials Science
• Computational Biology

Background:

• Skeletal muscle tissue exhibits complex passive mechanical behavior.
• Existing models often require macroscale constitutive assumptions and calibration.
• Understanding muscle mechanics is crucial for injury analysis and rehabilitation.

Purpose of the Study:

• To develop a novel microstructurally-based, multi-scale model for skeletal muscle passive behavior.
• To predict the effective mechanical response from microstructural properties without macroscale calibration.
• To investigate the anisotropic nature of muscle tissue mechanics.

Main Methods:

• A multi-scale modeling approach using homogenization of mechanical energies and stresses.
• Voigt-type homogenization combined with angular integration for the extracellular matrix.
• Derivation of the effective macroscopic energy in terms of strain invariants.

Main Results:

• The model predicts a tensile stiffness transverse to muscle fibers that is greater than along the fiber direction.
• Muscle tissue exhibits a general transversely isotropic behavior, not just classical fiber reinforcement.
• The model's predictions are a direct consequence of microstructural component stiffness and arrangement.

Conclusions:

• The developed model accurately captures the passive mechanical behavior of skeletal muscle based on its microstructure.
• The model eliminates the need for macroscale constitutive assumptions, offering a more fundamental approach.
• The findings highlight the transversely isotropic nature of muscle tissue, impacting biomechanical simulations and applications.