Architectural model for muscle growth during maturation.

Area of Science:

• Biomechanics
• Skeletal Muscle Physiology
• Computational Modeling

Background:

• Skeletal muscle mechanical properties are significantly influenced by muscle architecture parameters like fascicle length and pennation angle.
• Muscle architecture must adapt to the growth of an organism during maturation.
• Predicting these adaptations is crucial for understanding muscle function across different ages.

Purpose of the Study:

• To develop a predictive model for 3D fascicle architecture in unipennate muscles across various ages.
• To incorporate age-related changes in muscle belly length, fascicle length, and pennation angle into the model.
• To validate the model's predictions using experimental data and existing literature.

Main Methods:

• Collected novel 3D muscle architecture data for the rabbit M. plantaris in animals aged 29 to 106 days.
• Developed a computational model integrating experimental data on muscle growth and architectural parameter changes.
• Validated model predictions against literature data for rabbit M. soleus and M. gastrocnemius medialis.

Main Results:

• Observed significant increases in M. plantaris muscle belly length (73%), mean fascicle length (39%), and mean pennation angle (14%) with age.
• The developed model demonstrated good accuracy, with a -1.0 ± 8.6% error in predicting aponeurosis length, width, muscle height, and mass.
• Model predictions aligned well with interindividual variations found in literature data.

Conclusions:

• The developed 3D muscle architecture model effectively predicts age-related changes in unipennate muscles.
• The model's accuracy in predicting key architectural parameters and mass supports its utility.
• This predictive model can generate realistic architectural datasets for future biomechanical simulation studies.