Experimental Quantification of Balance Using Whole-Body Stability Regions from Postural Sway Exercises

Details

• Journal Article:
  Biomedical Engineering Online
• Personal Author:
  Akbas, Kubra ; Ratnakumar, Neethan ; Jones, Rachel M. ; Doss, Marianne ; Mummolo, Carlotta ; Daneault, Jean-Francois ; Zhou, Xianlian
• Description:
  Background: Comprehensive balance assessment is essential for evaluating balance deficiencies, particularly in individuals with limited mobility and increased fall risk. However, clinical balance assessments often rely on subjective scoring and simplified models that may not capture the full dynamics of human postural control. Additionally, center of pressure (COP)-based metrics and inverted pendulum models offer limited insight into whole-body balance ability. Balance regions (BRs) offer a more holistic approach by quantifying balanced center of mass (COM) states. Previously, BRs were used to assess the balancing capabilities of bipedal systems and humans in simulation; however, there is a lack of real-world implementations of whole-body BR analyses in human balance. Methods: This study presents a novel experimental framework to quantify human balance using COM-based BRs derived from large postural sway tasks. The participants comprised 22 healthy young adults who performed voluntary, supported, and perturbed anterior-posterior (AP) sway exercises while standing on force plates, with a full-body motion capture setup. COM trajectories were obtained from individualized musculoskeletal models in OpenSim to construct BRs, which were compared with linear inverted pendulum (LIP) limits. Key COM-based metrics included maximum AP margin of stability (MoS), maximum AP velocity, extrapolated COM (XcoM) range, and BR areas. COP measures (root mean square (RMS), range, 95% confidence ellipse area, mean AP velocity) and joint kinematics were also analyzed. Results: COM trajectories largely stayed within the LIP-based analytical boundaries, with BRs capturing individualized balance envelopes. Significant sex differences were observed in the maximum posterior MoS (p = 0.01974), XcoM range metrics (p < 0.03924), and BR areas (p < 0.045). COP metrics varied significantly across tasks in the RMS, 95% confidence ellipse area, and mean velocity (p < 0.02046), and inverse kinematics revealed distinct joint coordination patterns during sway; there was a significant sex difference in the COP range during perturbed backward sway (p = 0.03053). Conclusions: This study presents a novel, COM-based experimental framework for balance assessment that captures whole-body stability regions from dynamic postural tasks. BRs provide a quantitative and individualized measure of balance capacity beyond traditional metrics. This framework has potential for fall risk evaluation, balance training, and integration with wearable or markerless motion capture in clinical and neurorehabilitation settings.
• Subjects:
  Musculoskeletal System Occupational Health Postural Balance Safety
• Keywords:
  Author Keywords: Balance; Musculoskeletal Modeling; Motion Capture; Center Of Mass; Center Of Pressure; Inverse Kinematics Posture; Motion Studies; Biomechanics; Biomechanical Modeling; Biomechanical Engineering; Musculoskeletal System;
• Source:
  Biomed Eng Online 2026 Mar; :[Epub ahead of print]
• ISSN:
  1475-925X
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Journal Article
• Place as Subject:
  New Jersey ; New York City Region [OSHA]
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  54 pdf pages
• NIOSHTIC Number:
  nn:20071223
• Contact Point Address:
  Xianlian Zhou, Department of Biomedical Engineering, New Jersey Institute of Technology, 323 Dr Martin Luther King Jr Blvd, Newark, NJ, 07102, USA
• Email:
  alexzhou@njit.edu
• Federal Fiscal Year:
  2026
• Performing Organization:
  New Jersey Institute of Technology
• Peer Reviewed:
  True
• Start Date:
  20200901
• End Date:
  20240630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f0bb58d26d594f5795fa471fb8555395f459e4d5f7c0d284e8c41808f909633570d5b652c865d5395ef94ad8aa1a99d800a3f53a29f282dc54ed695eff1dac30
• Download URL:
  https://stacks.cdc.gov/view/cdc/258702/cdc_258702_DS1.pdf
• File Type:
  [PDF - 2.15 MB ]