Anatomically asymmetrical runners move more asymmetrically at the same metabolic cost

Area of Science:

• Biomechanics
• Human locomotion
• Exercise physiology

Background:

• Body structural asymmetries may influence locomotion efficiency.
• Previous research in horses linked asymmetry to reduced performance.
• The relationship between anatomical asymmetry, running kinematics, and metabolic cost in humans is not fully understood.

Purpose of the Study:

• To investigate the relationship between anatomical asymmetry, running kinematics, and metabolic cost of transport in male runners.
• To determine if training status (untrained, occasional, skilled) influences these relationships.

Main Methods:

• 3D Magnetic Resonance Imaging (MRI) was used to assess anatomical asymmetry in lower limbs of 19 male runners.
• 3D motion capture quantified running kinematics of the body's center of mass at various speeds.
• Metabolic consumption was measured to calculate the cost of transport.

Main Results:

• No significant correlation was found between anatomical or kinematic asymmetry and the metabolic cost of transport.
• A significant correlation existed between anatomical symmetry and kinematic symmetry.
• Skilled runners demonstrated higher levels of kinematic symmetry during running.

Conclusions:

• Anatomical asymmetry significantly affects running kinematics, but this effect does not translate to increased metabolic cost of transport.
• The locomotor system may employ plastic compensation to mitigate energy expenditure despite kinematic asymmetries.
• Running economy appears unaffected by structural asymmetries, regardless of training experience.