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Identifying the control structure of multijoint coordination during pistol shooting
J P Scholz1, G Schöner, M L Latash
1Department of Physical Therapy and Interdisciplinary Neuroscience Program, University of Delaware, Newark, DE 19716, USA. jpscholz@udel.edu
Experimental Brain Research
|January 9, 2001
Summary
The motor control system selectively releases joint configurations irrelevant to task success from tight control. This strategy optimizes multijoint movement by stabilizing essential variables while allowing flexibility in non-essential ones.
Area of Science:
- Motor control
- Biomechanics
- Robotics
Background:
- The control of multijoint movements involves managing numerous degrees of freedom.
- The motor system must stabilize essential task variables despite this complexity.
Purpose of the Study:
- To investigate the motor control system's strategy for constraining joint configurations.
- To test the hypothesis that task-irrelevant joint variations are less controlled.
Main Methods:
- Analysis of arm joint angles during a laser pistol shooting task.
- Decomposition of joint configuration variability using the uncontrolled manifold (UCM) hypothesis.
- Comparison of variability parallel and perpendicular to UCMs.
Main Results:
- Relative gun orientation to the target was the key task variable.
- Joint configuration fluctuations affecting gun orientation were significantly reduced.
- Control strategies varied across movement phases, with spatial position constraints relevant early on.
Conclusions:
- The motor system employs a selective control strategy, releasing irrelevant joint variations.
- The uncontrolled manifold principle effectively captures coordination structures for essential task variables.
- This approach reveals how motor control optimizes performance by managing degrees of freedom.
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