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Kinematic coordination in human gait: relation to mechanical energy cost
L Bianchi1, D Angelini, G P Orani
1Human Physiology Section, Scientific Institute S. Lucia, National Research Council, University of Tor Vergata, 00179 Rome, Italy.
Journal of Neurophysiology
|May 30, 1998
Summary
Human gait mechanics reveal how body segment angles change with walking speed. This study found that the orientation of angular covariation planes predicts mechanical energy expenditure, suggesting a nervous system strategy for efficient locomotion.
Area of Science:
- Biomechanics
- Human Locomotion
- Kinetics and Kinematics
Background:
- Human walking involves complex coordination of multiple body segments.
- Understanding the relationship between segment motion and energy expenditure is crucial for analyzing gait efficiency.
Purpose of the Study:
- To investigate the three-dimensional angular covariation of body segments during walking at various speeds.
- To determine the relationship between the orientation of this angular covariation and mechanical energy expenditure.
Main Methods:
- Recorded 3D motion and ground reaction forces in 24 subjects walking at freely chosen speeds (0.4–2.6 m/s).
- Analyzed the time course of elevation angles for trunk, pelvis, thigh, shank, and foot in the sagittal plane.
- Calculated mass-specific mean absolute power (Pu) as a measure of mechanical work during the gait cycle.
Main Results:
- Thigh, shank, and foot elevation angles showed tightly coupled, ample changes forming regular loops constrained on a plane.
- This plane of angular covariation systematically rotated with increasing walking speed (V).
- Plane orientation (u3t) correlated with net mechanical power (Pu), with specific orientations linked to individual energy expenditure levels.
Conclusions:
- The orientation of the angular covariation plane is a reliable predictor of an individual's mechanical energy expenditure during walking.
- Parametric tuning of this plane may represent a neural strategy for optimizing and limiting energy costs during locomotion.
- Findings provide insights into the control mechanisms underlying efficient human gait.