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Experimental Methods to Study Human Postural Control
Published on: September 11, 2019
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Interactions between initial posture and task-level goal explain experimental variability in postural responses to
Tom Van Wouwe1, Lena H Ting2,3, Friedl De Groote1
1Department of Movement Sciences, KU Leuven, Leuven, Belgium.
Journal of Neurophysiology
|December 16, 2020
Summary
Standing balance responses vary due to initial posture and individual goals. Computational modeling revealed that initial body position and prioritizing effort versus stability explain these variations in postural control.
Area of Science:
- Biomechanics
- Human Movement Science
- Motor Control
Background:
- Postural responses to balance perturbations exhibit significant variability within and across individuals.
- Understanding the sources of this variability is crucial for identifying factors influencing balance control and potential differences between populations.
Purpose of the Study:
- To identify and quantify the sources of variability in postural responses to balance perturbations.
- To investigate the interplay between initial posture and task-level goals in modulating postural control strategies.
Main Methods:
- Experimental collection of postural responses to unpredictable backward support-surface translations in young adults.
- Computational modeling using predictive simulations to assess causal relationships between posture, goals, and response variability.
- Analysis of kinematic data, including center of mass (COM) position and trunk lean, during postural adjustments.
Main Results:
- Maximal trunk lean during postural responses showed high variability within (mean range 28.3°) and across subjects (range of means 39.9°).
- Initial center of mass (COM) position significantly influenced the use of hip strategy, with more anterior COM positions increasing its utilization (subject-specific R²=0.29-0.82).
- Task-level goals (effort minimization vs. stability prioritization) explained intersubject variability, while interactions between initial posture and goals explained intrasubject variability differences.
Conclusions:
- Trial-by-trial variations in initial posture are a primary driver of within-subject variability in postural responses.
- Individual differences in task-level goals, such as prioritizing effort or stability, explain intersubject variability in postural strategies.
- Understanding these variability factors is essential for studying movement origins and differences across groups, with implications for populations like older adults exhibiting increased sway.
