Hip extensor fatigue alters hip and knee coupling dynamics during single-limb step-downs: A randomized controlled...

Area of Science:

• Biomechanics
• Motor Control
• Sports Medicine

Background:

• Impaired hip muscle function is linked to movement coordination deficits.
• These deficits can increase the risk of lower extremity injuries.

Purpose of the Study:

• To investigate alterations in hip and knee coordination during single-limb step-downs after hip extensor fatigue.
• To analyze kinematic and coordination changes using cross recurrence quantification analyses.

Main Methods:

• Forty participants underwent a randomized controlled trial with a hip extensor fatigue or sham protocol.
• Single-limb step-downs were performed before and after the protocol.
• Sagittal and frontal plane kinematics and nonlinear coordination measures were analyzed.

Main Results:

• Hip extensor fatigue reduced strength by 22.2% in the fatigue group.
• Kinematic magnitude and variability did not change significantly.
• Fatigue increased cross determinism and mean line in hip-knee coupling, indicating greater predictability and less adaptability.

Conclusions:

• Hip extensor fatigue leads to more predictable, less adaptable hip and knee coupling during step-downs.
• These findings offer insights into how motor control is reflected in coupled movement patterns.
• Understanding these changes may help in injury prevention strategies.