Upper-Body Neuromechanical Coordination Strategies During Fatiguing Sustained Dead Hangs in Climbers

Area of Science:

• Biomechanics
• Motor Control
• Sports Science

Background:

• Climbing performance relies on sustained upper-body strength and coordination.
• Fatigue significantly impacts motor control and joint-muscle strategies during isometric tasks.

Purpose of the Study:

• To investigate joint and muscle coordination adaptations during fatiguing dead hangs.
• To understand the relationship between joint coordination variability and muscle synergies under fatigue.

Main Methods:

• Eleven climbers performed dead hangs to failure.
• Joint coordination variability (rCV) analyzed using kinematic data.
• Muscle coordination assessed via EMG coherence (β/γCOH) and mutual information (β/γMI) in beta and gamma bands.

Main Results:

• Fatigue decreased wrist coordination variability (rCV) and increased muscle coordination (βCOH, βMI, γMI) in specific muscle groups.
• Inverse correlations found between wrist rCV and muscle coordination measures.
• Findings suggest a multi-level compensatory strategy involving joint and muscle adjustments.

Conclusions:

• Upper-body coordination strategies adapt under fatigue during dead hangs.
• Distal joint behavior becomes more constrained, while proximal and local muscle coordination is reinforced.
• These adaptations offer insights into maintaining climbing performance during prolonged isometric exertion.