Full-Field Strain Measurements of the Muscle-Tendon Junction Using X-ray Computed Tomography and Digital Volume...

Area of Science:

• Biomechanics
• Musculoskeletal Research
• Medical Imaging

Background:

• The muscle-tendon junction (MTJ) is critical for force transmission but prone to injury.
• Understanding MTJ mechanical behavior is vital for injury treatment and prevention.
• Previous studies lacked detailed 3D strain analysis at the MTJ.

Purpose of the Study:

• To characterize the full-field 3D strain distribution at the mouse MTJ under tensile load.
• To investigate the mechanical behavior of the MTJ during loading.
• To identify regions at high risk of damage within the MTJ.

Main Methods:

• Harvesting and staining of mouse Achilles tendon and gastrocnemius muscle MTJ.
• In situ X-ray computed tomography (XCT) for high-resolution imaging.
• Digital volume correlation (DVC) to compute 3D strain distribution.

Main Results:

• Quantified high peak strains: 120,000 µε (εp1), 160,000 µε (γ), and 120,000 µε (εVM) at the MTJ.
• Observed strain reduction away from the MTJ into muscle and tendon tissues.
• Demonstrated strain concentration specifically at the MTJ interface.

Conclusions:

• The MTJ experiences significant strain concentration, making it susceptible to injury.
• This detailed strain mapping provides insights into MTJ injury mechanisms.
• Findings aid in developing strategies for treating and preventing MTJ tears.