How Different Velocity-Loss Thresholds Impact Acute Neuromuscular Fatigue in Flywheel Resistance Training

Area of Science:

• Sports Science
• Exercise Physiology
• Biomechanics

Background:

• Flywheel resistance training enhances athletic performance and reduces injury risk.
• Understanding neuromuscular fatigue is crucial for optimizing training protocols.

Purpose of the Study:

• To evaluate how different velocity-loss thresholds and moments of inertia affect immediate postexercise neuromuscular fatigue during flywheel half-squat exercises.
• To determine the optimal parameters for flywheel training to minimize unwanted fatigue.

Main Methods:

• A crossover design study involving 20 healthy participants.
• Participants completed 9 conditions combining 3 inertia levels (0.050, 0.100, 0.150 kg·m²) and 3 velocity-loss thresholds (5%, 10%, 15%).
• Neuromuscular performance was assessed using peak isometric force, maximum rate of force development, and countermovement jump tests before and after exercise.

Main Results:

• Peak isometric force decreased significantly by approximately 15.58%.
• Maximum rate of force development was affected by time and velocity-loss threshold, with 15% loss causing greater fatigue than 5% or 10%.
• Countermovement jump performance significantly decreased with higher inertia and velocity loss (15% > 10% ≈ 5%), particularly impacting high-velocity actions.

Conclusions:

• Velocity losses exceeding 10%, especially at higher inertia (0.150 kg·m²), lead to significant neuromuscular fatigue.
• Velocity-based training allows coaches to individualize training volume and manage acute fatigue levels effectively.
• These findings provide practical guidance for optimizing flywheel resistance training protocols.