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Kinematic analysis of cat hindlimb stepping
1Department of Physiology, University of Minnesota School of Medicine, Minneapolis 55455, USA.
Journal of Neurophysiology
|December 1, 1995
Summary
Neural control of cat hindlimb stepping is simpler than previously thought. Limb mechanics and environmental interactions, not complex neural commands, largely dictate movement details.
Area of Science:
- Biomechanics
- Neuroscience
- Locomotion analysis
Background:
- Locomotion involves complex multijointed limb movements.
- Understanding limb control requires dissociating neuronal and mechanical factors.
- Primate arm control principles may apply to legged locomotion.
Purpose of the Study:
- Analyze cat hindlimb stepping kinematics.
- Investigate neuronal vs. mechanical factors in limb control.
- Apply concepts from arm movement control to locomotion.
Main Methods:
- Recorded and analyzed cat hindlimb kinematics during over-ground locomotion.
- Represented limb movement using limb segment orientation angles.
- Reconstructed limb movement from segment trajectories and compared with actual movement.
Main Results:
- Limb segment orientation angles followed invariant sawtooth waveforms.
- Limb-ground interaction explained stance phase differences.
- Limb inertia and muscle power explained swing phase differences.
Conclusions:
- Overall limb kinematics in stepping are controlled by segment orientation parameters.
- Hindpaw endpoint position is determined by segment trajectory timing and amplitude.
- Detailed limb kinematics result from mechanics and environment, simplifying neural control.