Leg asymmetries and coordination dynamics in walking

Area of Science:

• Biomechanics
• Human Motor Control
• Dynamical Systems Theory

Background:

• Interlimb coordination models, such as the Haken-Kelso-Bunz model, explain coordinated movements.
• Understanding how asymmetries between limbs influence coordination is crucial for human locomotion research.

Purpose of the Study:

• To investigate the impact of leg asymmetries on human walking coordination.
• To test the predictions of interlimb coordination models in a treadmill walking task.
• To examine the influence of metronome cues and leg loading on coordination and perception-action coupling.

Main Methods:

• Participants walked on a treadmill under various leg asymmetry conditions created by ankle loads (0, 3, 6 kg).
• Experiments were conducted with and without a metronome to control stride rate.
• Stride period, coordination patterns, and perception-action coupling were analyzed.

Main Results:

• Increased leg mass led to a slower stride rate, consistent with predictions from Huygens' law and the hybrid pendulum-spring model.
• Leg asymmetries caused deviations from antiphase coordination, supporting extended Haken-Kelso-Bunz model predictions.
• Perception-action coordination was modulated by leg asymmetry and the presence of a metronome.

Conclusions:

• Leg asymmetries significantly influence interlimb coordination during human walking.
• Existing dynamical systems models partially predict the observed effects of leg loading on gait.
• Findings suggest that principles of interlimb coordination observed in laboratory settings are applicable to naturalistic walking behaviors.