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Updated: Jul 8, 2026
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A Modified Lean and Release Technique to Emphasize Response Inhibition and Action Selection in Reactive Balance
Published on: March 19, 2020
Automated postural responses are modified in a functional manner by instruction
Vivian Weerdesteyn1, Andrew C Laing, Stephen N Robinovitch
1Department of Rehabilitation, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands. v.weerdesteyn@reval.umcn.nl
Experimental Brain Research
|January 15, 2008
Summary
Automated postural responses occur even when not needed for balance recovery. The central nervous system can selectively downregulate these responses based on task instructions, demonstrating functional motor control.
Area of Science:
- Neuroscience
- Biomechanics
- Motor Control
Background:
- Upright balance restoration relies on automated, stereotyped postural responses.
- These responses can be modulated by cognitive factors like instructions.
- The CNS's handling of postural responses when they conflict with task goals is unclear.
Purpose of the Study:
- To investigate the effect of instructions on automated postural responses.
- To examine how the central nervous system (CNS) manages postural responses when they are not beneficial for task completion.
Main Methods:
- Participants were instructed to either recover balance (BR trials) or fall safely (F trials) after release from an inclined posture.
- Postural responses in neck, trunk, shoulder, and leg muscles were recorded using EMG.
- Trials were conducted in backward and leftward perturbation directions.
Main Results:
- Participants successfully followed instructions, stepping in BR trials and suppressing steps in F trials.
- EMG recordings showed similar postural response onset latencies (70-130 ms) in both conditions, with slight delays in F trials.
- Response amplitudes differed significantly and early between BR and F trials, being higher in BR trials.
Conclusions:
- A balance perturbation always elicits a postural response, regardless of task demands.
- The CNS can selectively downregulate postural responses when they are not functionally required.
- Postural responses are integrated into motor output in a goal-oriented manner.
