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Asymmetric Walkway: A Novel Behavioral Assay for Studying Asymmetric Locomotion
Published on: January 15, 2016
Control and function of arm swing in human walking and running
Herman Pontzer1, John H Holloway, John H Holloway
1Department of Anthropology, Washington University, 119 McMillan Hall, Saint Louis, MO 63130, USA. hpontzer@artsci.wustl.edu
The Journal of Experimental Biology
|February 3, 2009
Summary
Human arm swing during walking and running is passive. Arms act as mass dampers, reducing torso rotation, with movement powered by the lower body, not active shoulder muscles.
Area of Science:
- Biomechanics
- Human Locomotion
- Human Physiology
Background:
- Arm swing is a key component of human walking and running.
- The precise role of arm swing, whether active or passive, remains debated.
- Understanding arm swing's function is crucial for analyzing gait dynamics and energy expenditure.
Purpose of the Study:
- To test the hypothesis that arm swing acts as a passive mass damper.
- To investigate if arm swing is powered by lower body movement rather than shoulder muscles.
- To determine the effect of altered arm inertia on locomotor cost and upper body kinematics.
Main Methods:
- 10 healthy adults walked and ran on a treadmill.
- Experimental conditions included control, no arms, and arm weights.
- Measurements included locomotor cost, deltoid muscle activity, and 3D kinematics.
Main Results:
- Altering arm inertia affected head yaw and shoulder-pelvis phase differences, supporting passive damping.
- Restricting arm swing did not change locomotor cost.
- Deltoid muscle activity was simultaneous, not alternating, suggesting no active driving role.
Conclusions:
- Results support a passive arm swing hypothesis for human walking and running.
- The trunk and shoulders act as elastic linkages, with arms functioning as passive mass dampers.
- Upper body movement during locomotion is primarily powered by the lower body.
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