Comparison of Modular Control during Side Cutting before and after Fatigue

Area of Science:

• Biomechanics
• Motor Control
• Sports Science

Background:

• Understanding trunk and lower limb muscle coordination is crucial for efficient and safe movement.
• Fatigue is known to alter neuromuscular control, potentially increasing injury risk during dynamic activities like sidestepping.

Purpose of the Study:

• To investigate the coordination patterns of trunk and lower limb muscles during sidestep movements.
• To compare these muscle coordination patterns before and after a fatigue-inducing intervention.

Main Methods:

• Electromyography (EMG) data were collected during sidestep tasks.
• Nonnegative Matrix Factorization (NMF) was employed to extract muscle synergies.
• A scalar product was used to quantify the similarity of muscle synergies before and after fatigue.

Main Results:

• Three distinct muscle synergies were identified, remaining consistent before and after fatigue.
• A key synergy involving the internal oblique/transversus abdominis, rectus femoris, and adductor muscles was identified for hip abduction suppression.
• The activation timing of this specific synergy was significantly delayed post-fatigue (P = 0.028).

Conclusions:

• While muscle synergies themselves were preserved, the altered activation timing post-fatigue suggests a potential decrease in hip stability.
• The delayed activation may lead to reduced hip control during sidestep maneuvers, possibly increasing susceptibility to injury.