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Anticipatory Postural Adjustments and kinematic arm features when postural stability is manipulated
Bianca Callegari1, Ghislain Saunier2, Manuela Brito Duarte1
1Laboratório de Estudos da Motricidade Humana, Universidade Federal do Pará, Belém, Brazil.
Peerj
|March 27, 2018
Summary
Anticipatory Postural Adjustments (APAs) facilitate limb movement and counteract perturbations, regardless of postural stability. Challenging stability impacts reaction time and arm movement kinematics during pointing tasks.
Area of Science:
- Neuroscience
- Biomechanics
- Motor Control
Background:
- Classical view: Anticipatory Postural Adjustments (APAs) counteract movement disturbances.
- Controversy exists regarding APAs' role in facilitating accurate movement execution.
- Arm kinematics are traditionally used to infer motor planning for arm movements.
Purpose of the Study:
- To investigate the role of APAs in facilitating upper-limb pointing movements.
- To differentiate the influence of postural stability on APAs and arm kinematics.
- To understand how motor planning is affected by postural constraints during a pointing task.
Main Methods:
- Participants performed a pointing task towards a target light.
- Postural stability was manipulated across three conditions: Standing (Up), Sit without feet support (SitUnsup), and Sit with feet support (SitSup).
- Upper-limb kinematics and APAs were recorded and analyzed.
Main Results:
- Challenging postural stability (SitUnsup) increased reaction time and movement duration.
- Higher postural stability (SitSup) resulted in greater peak arm velocity and shorter deceleration time.
- APAs were present across all postural stability conditions, suggesting a consistent role.
Conclusions:
- APAs appear to facilitate limb movement and counteract perturbations, independent of postural stability.
- Postural stability significantly influences upper-limb motor planning and kinematics during pointing.
- The degree of postural stability and the sitting/standing posture are critical factors in APAs and motor planning.
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