Muscle stiffness estimation using a system identification technique applied to evoked mechanomyogram during cycling...

Area of Science:

• Exercise Physiology
• Biomechanical Engineering
• Muscle Physiology

Background:

• Understanding muscle mechanics during dynamic activities like cycling is crucial.
• Quantifying muscle stiffness non-invasively provides insights into muscle function and fatigue.

Purpose of the Study:

• To develop a novel method for extracting the evoked mechanomyogram (MMG) during cycling exercise.
• To investigate the relationship between muscle stiffness and cycling parameters such as cadence, workload, and power.

Main Methods:

• Developed a technique to isolate evoked MMG signals from the vastus lateralis muscle using electrical stimulation during cycling.
• Employed a capacitor microphone to record MMG signals.
• Utilized synchronous averaging and signal subtraction to extract evoked MMG.
• Estimated muscle stiffness by analyzing the evoked MMG system's transfer function poles and muscle mass.

Main Results:

• Successfully extracted evoked MMG signals during cycling exercise.
• Muscle stiffness ranged from 186-626 N/m.
• Demonstrated a positive correlation between muscle stiffness and applied workloads and power output.

Conclusions:

• The developed method effectively assesses muscle stiffness during cycling.
• Muscle stiffness is a dynamic property that increases with higher workloads and power output in the vastus lateralis muscle.