Coordination of the ankle joint complex during walking

Area of Science:

• Biomechanics
• Human Locomotion
• Musculoskeletal System

Background:

• The ankle and rearfoot joints, talocrural and subtalar, govern complex motions.
• The subtalar joint's orientation suggests a potential mechanical coupling between coronal (inversion/eversion) and transverse (adduction/abduction) plane movements.

Purpose of the Study:

• To investigate the relationship between rearfoot inversion/eversion and adduction/abduction during walking.
• To compare simple mechanical coupling with dynamic muscular control in explaining these joint movements.

Main Methods:

• Employed both Pearson's correlation and linear systems analysis (dynamic analysis) on videography data.
• Collected motion data from 43 adults over five walking strides, analyzing leg and rearfoot marker movements.
• Utilized coherence square function to quantify the variance explained by dynamic relationships, analogous to correlation squared.

Main Results:

• Pearson's correlation squared (r(P)(2)) accounted for only 26% of the variance.
• Dynamic analysis (overall coherence) explained 62% of the variance, more than double that of simple correlation.
• Demonstrated a significant difference between simple mechanical coupling and dynamic control of rearfoot motion.

Conclusions:

• Simple mechanical coupling between inversion/eversion and adduction/abduction is insufficient to explain observed walking dynamics.
• Muscular control and visco-elastic passive elements are the primary drivers of rearfoot motion during walking.
• Dynamic analysis provides a more comprehensive understanding of the complex biomechanics of the ankle and rearfoot during locomotion.