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Published on: April 12, 2016
Postural dependence of muscle actions: implications for neural control
C A Buneo1, J F Soechting, M Flanders
1Department of Physiology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Summary
The nervous system uses a simple strategy to control arm reaching, accounting for how shoulder muscle actions change with posture due to musculoskeletal geometry.
Area of Science:
- Biomechanics
- Neuroscience
- Human motor control
Background:
- Neural control of reaching involves complex muscle activation patterns.
- Arm musculoskeletal geometry imposes constraints on motor control solutions.
Purpose of the Study:
- To quantify postural variations in the mechanical actions of shoulder muscles.
- To understand how musculoskeletal geometry constrains neural control of reaching.
Main Methods:
- Electrical stimulation of six human shoulder muscles.
- Measurement of muscle forces and torques using a six-degree-of-freedom force-torque transducer.
- Data collection across up to 29 different arm postures per experiment.
Main Results:
- Shoulder muscle mechanical actions systematically varied with arm posture.
- This variation was consistent regardless of the reference frame used.
- The observed dependence suggests a simple neural control strategy.
Conclusions:
- Musculoskeletal geometry significantly influences shoulder muscle function during reaching.
- The nervous system likely employs a straightforward strategy to adapt to these geometric constraints.
- This research provides insight into the neural control of human arm movement.
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