Fatigue profile: a numerical method to examine fatigue in cycle ergometry

Area of Science:

• Sports Science
• Exercise Physiology
• Biomechanics

Background:

• Muscle fatigue assessment is crucial in exercise science.
• Conventional fatigue index (FI) has limitations in capturing temporal dynamics.
• Isokinetic cycle ergometry is a common tool for performance testing.

Purpose of the Study:

• Introduce and validate a novel numerical method, the Fatigue Profile, for characterizing muscle fatigue.
• Compare the efficacy of the Fatigue Profile against the conventional fatigue index (FI).
• Analyze the temporal development of fatigue during isokinetic cycling.

Main Methods:

• Developed a Fatigue Profile method based on the decline of peak power output during isokinetic cycling.
• Utilized a fourth-degree polynomial to model peak power data over time.
• Calculated the first derivative of the polynomial model to represent the rate of power change (Fatigue Profile).
• Compared results with the conventional fatigue index (FI) using data from a trained athlete.

Main Results:

• The conventional FI indicated minor fatigue differences between two trials (-35 Ws⁻¹ vs. -32 Ws⁻¹).
• The Fatigue Profile revealed significant temporal differences, showing maximum power decline rates of -65 Ws⁻¹ at 6s (Trial 1) and -146 Ws⁻¹ immediately (Trial 2).
• The new method effectively characterized the dynamic nature of muscle fatigue.

Conclusions:

• The Fatigue Profile method provides a more detailed characterization of muscle fatigue temporal development than the conventional FI.
• This approach enhances the understanding of fatigue mechanisms in isokinetic exercise.
• The Fatigue Profile has potential applications in various experimental conditions and research.