{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T15:22:21Z","timestamp":1780327341913,"version":"3.54.1"},"reference-count":21,"publisher":"Wiley","license":[{"start":{"date-parts":[[2021,6,11]],"date-time":"2021-06-11T00:00:00Z","timestamp":1623369600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST-106-2221-E-110-044"],"award-info":[{"award-number":["MOST-106-2221-E-110-044"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST-108-2221-E-027-066"],"award-info":[{"award-number":["MOST-108-2221-E-027-066"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Healthcare Engineering"],"published-print":{"date-parts":[[2021,6,11]]},"abstract":"<jats:p>By assuming that the human body rotates primarily around the ankle joint in the sagittal plane, the human body has been modelled as a single inverted pendulum (IP) to simulate the human quiet stance. Despite its popularity, the validity of the IP model has been challenged in many studies. Rather than testing the validity of the IP model as a true or false question, this work proposes a feature to quantify the degree of validity of the IP model. The development of the proposed feature is based on the fact that the IP model predicts that the horizontal acceleration of COM is proportional to the COP error which is defined as the difference between the center of pressure (COP) and the vertical projection of the center of mass (COM). Since the horizontal components of the acceleration of COM and the ground reaction force (GRF) are always proportional, the proposed feature is the correlation coefficient between the anterior-posterior (AP) components of GRF and the COP error. The efficacy of the proposed feature is demonstrated by comparing its differences for individuals in two age groups (18\u201324 and 65\u201373 years) in quiet standing. The experimental results show that the IP model is more suited for predicting the motion of the older group than the younger group. Our results also show that the proposed feature is more sensitive to aging effects than one of the most reliable and accurate COP-based postural stability features.<\/jats:p>","DOI":"10.1155\/2021\/8884614","type":"journal-article","created":{"date-parts":[[2021,6,11]],"date-time":"2021-06-11T18:50:09Z","timestamp":1623437409000},"page":"1-6","source":"Crossref","is-referenced-by-count":6,"title":["Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing"],"prefix":"10.1155","volume":"2021","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8677-1628","authenticated-orcid":true,"given":"Jia-Li","family":"Sung","sequence":"first","affiliation":[{"name":"Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7076-8726","authenticated-orcid":true,"given":"Chih-Yuan","family":"Hong","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6285-1802","authenticated-orcid":true,"given":"Chin-Hsuan","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Occupational Therapy, Kaohsiung Municipal Kai-Syuan Psychiatric Hospital, Kaohsiung 80276, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3914-1049","authenticated-orcid":true,"given":"Posen","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Occupational Therapy, I-Shou University, Kaohsiung 82445, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6256-355X","authenticated-orcid":true,"given":"Lan-Yuen","family":"Guo","sequence":"additional","affiliation":[{"name":"Department of Sports Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4392-0179","authenticated-orcid":true,"given":"Nan-Hung","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4894-7055","authenticated-orcid":true,"given":"Chen-Wen","family":"Yen","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan"},{"name":"Department of Physical Therapy, College of Health Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan"},{"name":"Neuroscience Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4470-649X","authenticated-orcid":true,"given":"Lih-Jiun","family":"Liaw","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, College of Health Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan"},{"name":"Neuroscience Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan"},{"name":"Department of Physical Medicine and Rehabilitation, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan"},{"name":"Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","reference":[{"key":"1","doi-asserted-by":"publisher","DOI":"10.1016\/0966-6362(96)82849-9"},{"issue":"3","key":"2","doi-asserted-by":"crossref","first-page":"1211","DOI":"10.1152\/jn.1998.80.3.1211","article-title":"Stiffness control of balance in quiet standing","volume":"80","author":"D. 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