{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T14:19:42Z","timestamp":1770992382465,"version":"3.50.1"},"reference-count":24,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,1,19]],"date-time":"2021-01-19T00:00:00Z","timestamp":1611014400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Objective: The main objective of the tests conducted was to analyze the position variability of the human body\u2019s center of gravity during propelling the wheelchair, and to demonstrate the properties enabling the description of this variability by means of plane figures with a symmetry axis. A secondary objective was to show the impact of the used manual propulsion type and the wheelchair inclination angle in relation to the plane on the dimensions of the position variability areas of the center of gravity. Method and materials: Three patients participated in the research representing 50 centiles of anthropometric dimensions. Each patient carried out fifteen measurement tests on three wheelchairs for three inclination angles of the wheelchair frame in relation to the level. Each measurement test consisted of five propulsion cycles for which the positions of the center of gravity were determined with the sampling frequency of 100 Hz. The measured positions of the center of gravity were approximated with ellipses containing 95.4% of the measurements conducted, assuming their dimension scaling basis in the form of the double value of standard deviation defined based on the registered results. Results: Based on the measurements conducted, the average values of five ellipses parameters were determined for nine cases in which a variable was the type of wheelchair propulsion and its inclination angle in relation to the level. The area of the highest variability of the position of the center of gravity was measured for the wheelchair with a multispeed transmission. The average dimensions of the ellipse semi-axis amounted to 108.53 mm for the semi-axis a and 29.75 for the semi-axis b, the average position of the ellipse center amounted to x = 114.51 mm and y = \u221210.53 mm, and the average inclination angle of the ellipse \u03b1 amounted to \u22126.92\u00b0. The area of the lowest variability of the position of the center of gravity was measured for the wheelchair with a hybrid transmission. In this case, the average dimensions of the ellipse semi-axis amounted to 64.07 mm for the semi-axis a and 33.85 for the semi-axis b; whereas, the average position of the ellipse center amounted to x = 245.13 mm and y = \u221228.24 mm, and the average inclination angle of the ellipse \u03b1 amounted to \u22120.56\u00b0.<\/jats:p>","DOI":"10.3390\/sym13010154","type":"journal-article","created":{"date-parts":[[2021,1,21]],"date-time":"2021-01-21T02:36:05Z","timestamp":1611196565000},"page":"154","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["The Symmetric Nature of the Position Distribution of the Human Body Center of Gravity during Propelling Manual Wheelchairs with Innovative Propulsion Systems"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0808-298X","authenticated-orcid":false,"given":"Bartosz","family":"Wieczorek","sequence":"first","affiliation":[{"name":"Institute of Machine Design, Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Pozna\u0144, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3456-3824","authenticated-orcid":false,"given":"Mateusz","family":"Kukla","sequence":"additional","affiliation":[{"name":"Institute of Machine Design, Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Pozna\u0144, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3120-778X","authenticated-orcid":false,"given":"\u0141ukasz","family":"Wargu\u0142a","sequence":"additional","affiliation":[{"name":"Institute of Machine Design, Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Pozna\u0144, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Smith, E.M., Mortenson, W.B., Mihailidis, A., and Miller, W.C. (2020). Understanding the task demands for powered wheelchair driving: A think-aloud task analysis. Disabil. Rehabil. Assist. Technol., 1\u20138.","DOI":"10.1080\/17483107.2020.1810335"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1249\/00005768-199201000-00017","article-title":"Effect of handrim velocity on mechanical efficiency in wheelchair propulsion","volume":"24","author":"Veeger","year":"1992","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1682\/JRRD.1990.01.0021","article-title":"Kinematics of sport wheelchair propulsion","volume":"27","author":"Coutts","year":"1990","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/S0003-9993(96)90166-5","article-title":"Electromyographic activity of shoulder muscles during wheelchair propulsion by paraplegic persons","volume":"77","author":"Mulroy","year":"1996","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"012062","DOI":"10.1088\/1757-899X\/776\/1\/012062","article-title":"Methods for measuring the position of the centre of gravity of an anthropotechnic human-wheelchair system in dynamic conditions","volume":"776","author":"Wieczorek","year":"2020","journal-title":"Mater. Sci. Eng. Conf. Ser."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1411","DOI":"10.1682\/JRRD.2013.11.0250","article-title":"Design and development of solar power-assisted manual\/electric wheelchair","volume":"51","author":"Chien","year":"2014","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"718","DOI":"10.1053\/apmr.2002.32455","article-title":"Propulsion patterns and pushrim biomechanics in manual wheelchair propulsion","volume":"83","author":"Boninger","year":"2002","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"339","DOI":"10.2165\/00007256-200131050-00005","article-title":"Wheelchair Propulsion Biomechanics","volume":"31","author":"Vanlandewijck","year":"2001","journal-title":"Sports Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1682\/JRRD.1992.07.0012","article-title":"Biomechanical analysis of wheelchair propulsion for various seating positions","volume":"29","author":"Lamontagne","year":"1992","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Russell, I.M., Wagner, E., Requejo, P., Mulroy, S., Flashner, H., and McNitt-Gray, J. (2019). Characterization of the shoulder net joint moment during manual wheelchair propulsion using four functional axes. J. Electromyogr. Kinesiol., 102340.","DOI":"10.1016\/j.jelekin.2019.07.010"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1916","DOI":"10.1016\/j.apmr.2009.05.022","article-title":"Manual Wheelchair Propulsion Patterns on Natural Surfaces During Start-Up Propulsion","volume":"90","author":"Koontz","year":"2009","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_12","first-page":"367","article-title":"Wheelchair stability: Effect of body position","volume":"32","author":"Kirby","year":"1995","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"86","DOI":"10.3389\/fbioe.2015.00086","article-title":"An Investigation of Bilateral Symmetry During Manual Wheelchair Propulsion","volume":"3","author":"Soltau","year":"2015","journal-title":"Front. Bioeng. Biotechnol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1810","DOI":"10.1080\/001401398185983","article-title":"Symmetry of the elbow kinematics during racing wheelchair propulsion","volume":"41","author":"Goosey","year":"1998","journal-title":"Ergonomics"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Wieczorek, B., Wargu\u0142a, \u0141., and Rybarczyk, D. (2020). Impact of a Hybrid Assisted Wheelchair Propulsion System on Motion Kinematics during Climbing up a Slope. Appl. Sci., 10.","DOI":"10.20944\/preprints202001.0287.v1"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"01006","DOI":"10.1051\/matecconf\/201925401006","article-title":"Problems of dynamometer construction for wheelchairs and simulation of push motion","volume":"254","author":"Wieczorek","year":"2019","journal-title":"MATEC Web Conf."},{"key":"ref_17","first-page":"625","article-title":"Optimum cycle frequencies in hand-rim wheelchair propulsion","volume":"58","author":"Veeger","year":"1989","journal-title":"Graefe\u2019s Arch. Clin. Exp. Ophthalmol."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Wieczorek, B., and Kukla, M. (2019). Effects of the performance parameters of a wheelchair on the changes in the position of the centre of gravity of the human body in dynamic condition. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0226013"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1016\/j.imavis.2005.10.007","article-title":"Human gait recognition at sagittal plane","volume":"25","author":"Zhang","year":"2007","journal-title":"Image Vis. Comput."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1682\/JRRD.2004.03.0385","article-title":"The biomechanics of wheelchair propulsion in individuals with and without upper-limb impairment","volume":"41","author":"Finley","year":"2004","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1586","DOI":"10.1111\/sms.13056","article-title":"Sprint performance and propulsion asymmetries on an ergometer in trained high- and low-point wheelchair rugby players","volume":"28","author":"Vegter","year":"2018","journal-title":"Scand. J. Med. Sci. Sports"},{"key":"ref_22","first-page":"374","article-title":"Measuring seating pressure, area, and asymmetry in persons with spinal cord injury","volume":"13","author":"Alm","year":"2003","journal-title":"Eur. Spine J."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1097\/00002060-199909000-00006","article-title":"Glenohumeral joint kinematics and kinetics for three coordinate system representations during wheelchair propulsion","volume":"78","author":"Cooper","year":"1999","journal-title":"Am. J. Phys. Med. Rehabil."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"214","DOI":"10.1080\/10790268.2005.11753815","article-title":"Effect of Fore-Aft Seat Position on Shoulder Demands During Wheelchair Propulsion: Part 1. A Kinetic Analysis","volume":"28","author":"Mulroy","year":"2005","journal-title":"J. Spinal Cord Med."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/13\/1\/154\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:13:01Z","timestamp":1760159581000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/13\/1\/154"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,1,19]]},"references-count":24,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2021,1]]}},"alternative-id":["sym13010154"],"URL":"https:\/\/doi.org\/10.3390\/sym13010154","relation":{},"ISSN":["2073-8994"],"issn-type":[{"value":"2073-8994","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,1,19]]}}}