Development of a symmetry index using discrete variables

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Quantifying lower extremity movement symmetry is crucial for understanding running mechanics and identifying potential injury risks.
• Existing methods may not fully capture the dynamic nature of gait symmetry during the stance phase.

Purpose of the Study:

• To introduce and evaluate a novel methodology for quantifying lower extremity movement symmetry during over-ground running.
• To analyze symmetry across sagittal, transverse, and frontal planes, as well as a global index.

Main Methods:

• Seventeen subjects performed over-ground running trials over a force platform.
• Kinetic and kinematic data were collected, with 12 key variables selected for symmetry calculation.
• A formula was developed using the integral of the absolute difference between left and right leg stance phases.

Main Results:

• The new methodology provides distinct indices for sagittal, transverse, and frontal planes, alongside a global symmetry index.
• This allows for the identification of individuals with plane-specific symmetry or asymmetry.
• The method accounts for the entire stance phase and potential time lags between legs.

Conclusions:

• The developed methodology offers a comprehensive approach to quantifying lower extremity movement symmetry during running.
• It enables detailed analysis of gait patterns across multiple planes of motion.
• Future research should explore larger populations and incorporate flight phase analysis for a more complete understanding.