{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T05:48:52Z","timestamp":1791611332033,"version":"4.3.4"},"reference-count":36,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2021,10,5]],"date-time":"2021-10-05T00:00:00Z","timestamp":1633392000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2021,10,5]],"date-time":"2021-10-05T00:00:00Z","timestamp":1633392000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"Fostering Global Talents for Innovative Growth Program by Ministry of Trade, Industry, and Energy in Korea","award":["P0008748"],"award-info":[{"award-number":["P0008748"]}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Toe joint is known as one of the critical factors in designing a prosthetic foot due to its nonlinear stiffness characteristic. This stiffness characteristic provides a general feeling of springiness in the toe-off and it also affects the ankle kinetics. In this study, the toe part of the prosthetic foot was designed to improve walking performance. The toe joint was implemented as a single part suitable for 3D printing. The various shape factors such as curved shape, bending space, auxetic structure, and bending zone were applied to mimic human foot characteristics. The finite element analysis (FEA) was conducted to simulate terminal stance (from heel-off to toe-off) using the designed prosthetic foot. To find the structure with characteristics similar to the human foot, the optimization was performed based on the toe joint geometries. As a result, the optimized foot showed good agreement with human foot behavior in the toe torque-angle curve. Finally, the simulation conditions were validated by comparing with human walking data and it was confirmed that the designed prosthetic foot structure can implement the human foot function.<\/jats:p>","DOI":"10.1038\/s41598-021-98839-3","type":"journal-article","created":{"date-parts":[[2021,10,5]],"date-time":"2021-10-05T13:52:53Z","timestamp":1633441973000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Design of 3D printable prosthetic foot to implement nonlinear stiffness behavior of human toe joint based on finite element analysis"],"prefix":"10.1038","volume":"11","author":[{"given":"Hui-Jin","family":"Um","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heon-Su","family":"Kim","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Woolim","family":"Hong","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hak-Sung","family":"Kim","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pilwon","family":"Hur","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2021,10,5]]},"reference":[{"key":"98839_CR1","doi-asserted-by":"publisher","first-page":"2570","DOI":"10.1001\/jama.287.19.2570","volume":"287","author":"JA Beckman","year":"2002","unstructured":"Beckman, J. A., Creager, M. A. & Libby, P. Diabetes and atherosclerosis: Epidemiology, pathophysiology, and management. JAMA 287, 2570\u20132581 (2002).","journal-title":"JAMA"},{"key":"98839_CR2","doi-asserted-by":"publisher","first-page":"422","DOI":"10.1016\/j.apmr.2007.11.005","volume":"89","author":"K Ziegler-Graham","year":"2008","unstructured":"Ziegler-Graham, K., MacKenzie, E. J., Ephraim, P. L., Travison, T. G. & Brookmeyer, R. Estimating the prevalence of limb loss in the united states: 2005 to 2050. Arch. Phys. Med. Rehabil. 89, 422\u2013429 (2008).","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"98839_CR3","volume-title":"ASME 2017 Conference on Smart Materials. Adaptive Structures and Intelligent Systems","author":"H Tryggvason","year":"2017","unstructured":"Tryggvason, H., Starker, F., Lecomte, C. & Jonsdottir, F. Modeling of stiffness characteristics in a prosthetic foot. In ASME 2017 Conference on Smart Materials. Adaptive Structures and Intelligent Systems (American Society of Mechanical Engineers Digital Collection, 2017)."},{"key":"98839_CR4","doi-asserted-by":"publisher","first-page":"2","DOI":"10.1115\/1.4007824","volume":"134","author":"NP Fey","year":"2012","unstructured":"Fey, N. P., Klute, G. K. & Neptune, R. R. Optimization of prosthetic foot stiffness to reduce metabolic cost and intact knee loading during below-knee amputee walking: A theoretical study. J. Biomech. Eng. 134, 2 (2012).","journal-title":"J. Biomech. Eng."},{"key":"98839_CR5","doi-asserted-by":"publisher","first-page":"853","DOI":"10.1016\/0003-9993(93)90013-Z","volume":"74","author":"JF Lehmann","year":"1993","unstructured":"Lehmann, J. F., Price, R., Boswell-Bessette, S., Dralle, A. & Questad, K. Comprehensive analysis of dynamic elastic response feet: Seattle ankle\/lite foot versus sach foot. Arch. Phys. Med. Rehabil. 74, 853\u2013861 (1993).","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"98839_CR6","doi-asserted-by":"publisher","first-page":"147","DOI":"10.3109\/03093648409146077","volume":"8","author":"J Goh","year":"1984","unstructured":"Goh, J., Solomonidis, S., Spence, W. & Paul, J. Biomechanical evaluation of sach and uniaxial feet. Prosthet. Orthot. Int. 8, 147\u2013154 (1984).","journal-title":"Prosthet. Orthot. Int."},{"key":"98839_CR7","doi-asserted-by":"publisher","first-page":"17","DOI":"10.3109\/03093649709164526","volume":"21","author":"K Postema","year":"1997","unstructured":"Postema, K., Hermens, H. J., De Vries, J., Koopman, H. F. & Eisma, W. Energy storage and release of prosthetic feet part 1: Biomechanical analysis related to user benefits. Prosthet. Orthot. Int. 21, 17\u201327 (1997).","journal-title":"Prosthet. Orthot. Int."},{"key":"98839_CR8","doi-asserted-by":"crossref","first-page":"172988141770454","DOI":"10.1177\/1729881417704545","volume":"14","author":"D Dong","year":"2017","unstructured":"Dong, D., Ge, W., Liu, S., Xia, F. & Sun, Y. Design and optimization of a powered ankle-foot prosthesis using a geared five-bar spring mechanism. Int. J. Adv. Rob. Syst. 14, 1729881417704545 (2017).","journal-title":"Int. J. Adv. Rob. Syst."},{"key":"98839_CR9","doi-asserted-by":"publisher","first-page":"2375","DOI":"10.1109\/TNSRE.2017.2750113","volume":"25","author":"MK Shepherd","year":"2017","unstructured":"Shepherd, M. K. & Rouse, E. J. The VSPA foot: A quasi-passive ankle-foot prosthesis with continuously variable stiffness. IEEE Trans. Neural Syst. Rehabil. Eng. 25, 2375\u20132386 (2017).","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"98839_CR10","doi-asserted-by":"publisher","first-page":"1254","DOI":"10.1016\/j.mechatronics.2014.06.005","volume":"24","author":"J Zhu","year":"2014","unstructured":"Zhu, J., Wang, Q. & Wang, L. Effects of toe stiffness on ankle kinetics in a robotic transtibial prosthesis during level-ground walking. Mechatronics 24, 1254\u20131261 (2014).","journal-title":"Mechatronics"},{"key":"98839_CR11","doi-asserted-by":"publisher","first-page":"066007","DOI":"10.1088\/1748-3190\/aadf46","volume":"13","author":"EC Honert","year":"2018","unstructured":"Honert, E. C., Bastas, G. & Zelik, K. E. Effect of toe joint stiffness and toe shape on walking biomechanics. Bioinspir. Biomimetics 13, 066007 (2018).","journal-title":"Bioinspir. Biomimetics"},{"key":"98839_CR12","first-page":"1","volume":"20","author":"K Yamamoto","year":"2017","unstructured":"Yamamoto, K. Humanlike toe joint mechanism. Humanoid Robot. A Ref. 20, 1\u201322 (2017).","journal-title":"Humanoid Robot. A Ref."},{"key":"98839_CR13","doi-asserted-by":"publisher","first-page":"20180270","DOI":"10.1098\/rsif.2018.0270","volume":"15","author":"L Welte","year":"2018","unstructured":"Welte, L., Kelly, L. A., Lichtwark, G. A. & Rainbow, M. J. Influence of the windlass mechanism on arch-spring mechanics during dynamic foot arch deformation. J. R. Soc. Interface 15, 20180270 (2018).","journal-title":"J. R. Soc. Interface"},{"key":"98839_CR14","doi-asserted-by":"publisher","first-page":"2351","DOI":"10.1109\/TNSRE.2018.2877962","volume":"26","author":"EM Glanzer","year":"2018","unstructured":"Glanzer, E. M. & Adamczyk, P. G. Design and validation of a semi-active variable stiffness foot prosthesis. IEEE Trans. Neural Syst. Rehabil. Eng. 26, 2351\u20132359 (2018).","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"98839_CR15","doi-asserted-by":"crossref","unstructured":"Shepherd, M.\u00a0K. & Rouse, E.\u00a0J. Design of a quasi-passive ankle-foot prosthesis with biomimetic, variable stiffness. In 2017 IEEE International Conference on Robotics and Automation (ICRA), 6672\u20136678 (IEEE, 2017).","DOI":"10.1109\/ICRA.2017.7989788"},{"key":"98839_CR16","doi-asserted-by":"crossref","unstructured":"Hong, W., Paredes, V., Chao, K., Patrick, S. & Hur, P. Consolidated control framework to control a powered transfemoral prosthesis over inclined terrain conditions. In 2019 International Conference on Robotics and Automation (ICRA), 2838\u20132844 (IEEE, 2019).","DOI":"10.1109\/ICRA.2019.8794140"},{"key":"98839_CR17","unstructured":"Hong, W., Patrick, S. & Hur, P. Effect of toe stiffness on the push-off and joint trajectories for the powered transfemoral prosthesis: A pilot study. In 42nd Annual Conference of the American Society of Biomechanics (ASB) 2018 (2018)."},{"key":"98839_CR18","doi-asserted-by":"publisher","first-page":"4797","DOI":"10.1109\/TIE.2013.2293691","volume":"61","author":"J Zhu","year":"2013","unstructured":"Zhu, J., Wang, Q. & Wang, L. On the design of a powered transtibial prosthesis with stiffness adaptable ankle and toe joints. IEEE Trans. Ind. Electron. 61, 4797\u20134807 (2013).","journal-title":"IEEE Trans. Ind. Electron."},{"key":"98839_CR19","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1016\/j.compstruct.2017.05.001","volume":"175","author":"T Li","year":"2017","unstructured":"Li, T. & Wang, L. Bending behavior of sandwich composite structures with tunable 3d-printed core materials. Compos. Struct. 175, 46\u201357 (2017).","journal-title":"Compos. Struct."},{"key":"98839_CR20","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1016\/j.matdes.2018.01.034","volume":"142","author":"T Li","year":"2018","unstructured":"Li, T., Chen, Y., Hu, X., Li, Y. & Wang, L. Exploiting negative Poisson\u2019s ratio to design 3d-printed composites with enhanced mechanical properties. Mater. Des. 142, 247\u2013258 (2018).","journal-title":"Mater. Des."},{"key":"98839_CR21","doi-asserted-by":"publisher","first-page":"87","DOI":"10.1016\/j.compstruct.2016.01.079","volume":"142","author":"J-S Hwang","year":"2016","unstructured":"Hwang, J.-S. et al. Development of a bendable pyramidal kagome structure and its structural characteristics. Compos. Struct. 142, 87\u201395 (2016).","journal-title":"Compos. Struct."},{"key":"98839_CR22","unstructured":"Winter, D.\u00a0A. Biomechanics and motor control of human gait: Normal, elderly and pathological (1991)."},{"key":"98839_CR23","doi-asserted-by":"publisher","first-page":"871","DOI":"10.1016\/S0045-7949(02)00429-7","volume":"81","author":"R Ognjanovic","year":"2003","unstructured":"Ognjanovic, R. & Waterson, K. Finite element analysis modeling of ingot refusal conditions during the rolling process. Comput. Struct. 81, 871\u2013877 (2003).","journal-title":"Comput. Struct."},{"key":"98839_CR24","doi-asserted-by":"publisher","first-page":"85","DOI":"10.1016\/j.compscitech.2015.09.025","volume":"119","author":"E Farmand-Ashtiani","year":"2015","unstructured":"Farmand-Ashtiani, E., Alanis, D., Cugnoni, J. & Botsis, J. Delamination in cross-ply laminates: Identification of traction-separation relations and cohesive zone modeling. Compos. Sci. Technol. 119, 85\u201392 (2015).","journal-title":"Compos. Sci. Technol."},{"key":"98839_CR25","doi-asserted-by":"publisher","first-page":"177","DOI":"10.1016\/j.matdes.2018.01.028","volume":"142","author":"M Kucewicz","year":"2018","unstructured":"Kucewicz, M., Baranowski, P., Malachowski, J., Poplawski, A. & Platek, P. Modelling, and characterization of 3d printed cellular structures. Mater. Des. 142, 177\u2013189 (2018).","journal-title":"Mater. Des."},{"key":"98839_CR26","doi-asserted-by":"publisher","first-page":"229","DOI":"10.1080\/02701367.2002.10609016","volume":"73","author":"L Li","year":"2002","unstructured":"Li, L. & Hamill, J. Characteristics of the vertical ground reaction force component prior to gait transition. Res. Q. Exerc. Sport 73, 229\u2013237 (2002).","journal-title":"Res. Q. Exerc. Sport"},{"key":"98839_CR27","doi-asserted-by":"publisher","first-page":"77","DOI":"10.1016\/j.clinbiomech.2016.12.008","volume":"41","author":"I Villarrasa-Sapi\u00f1a","year":"2017","unstructured":"Villarrasa-Sapi\u00f1a, I., Serra-A\u00f1\u00f3, P., Pardo-Ib\u00e1\u00f1ez, A., Gonzalez, L.-M. & Garc\u00eda-Mass\u00f3, X. Relationship between body composition and vertical ground reaction forces in obese children when walking. Clin. Biomech. 41, 77\u201381 (2017).","journal-title":"Clin. Biomech."},{"key":"98839_CR28","doi-asserted-by":"publisher","first-page":"1833","DOI":"10.1589\/jpts.27.1833","volume":"27","author":"H Toda","year":"2015","unstructured":"Toda, H., Nagano, A. & Luo, Z. Age and gender differences in the control of vertical ground reaction force by the hip, knee and ankle joints. J. Phys. Ther. Sci. 27, 1833\u20131838 (2015).","journal-title":"J. Phys. Ther. Sci."},{"key":"98839_CR29","doi-asserted-by":"publisher","first-page":"108","DOI":"10.1016\/j.jtbi.2015.10.002","volume":"388","author":"S Sun","year":"2016","unstructured":"Sun, S., Huang, Y. & Wang, Q. Adding adaptable toe stiffness affects energetic efficiency and dynamic behaviors of bipedal walking. J. Theor. Biol. 388, 108\u2013118 (2016).","journal-title":"J. Theor. Biol."},{"key":"98839_CR30","doi-asserted-by":"publisher","first-page":"3978","DOI":"10.1016\/j.proeng.2011.08.745","volume":"15","author":"Y Yusoff","year":"2011","unstructured":"Yusoff, Y., Ngadiman, M. S. & Zain, A. M. Overview of nsga-ii for optimizing machining process parameters. Proced. Eng. 15, 3978\u20133983 (2011).","journal-title":"Proced. Eng."},{"key":"98839_CR31","doi-asserted-by":"publisher","first-page":"383","DOI":"10.2514\/1.21433","volume":"30","author":"Y-Z Luo","year":"2007","unstructured":"Luo, Y.-Z., Tang, G.-J. & Lei, Y.-J. Optimal multi-objective linearized impulsive rendezvous. J. Guid. Control. Dyn. 30, 383\u2013389 (2007).","journal-title":"J. Guid. Control. Dyn."},{"key":"98839_CR32","doi-asserted-by":"publisher","first-page":"151","DOI":"10.1016\/j.epsr.2004.07.002","volume":"73","author":"Y-Y Hong","year":"2005","unstructured":"Hong, Y.-Y. & Lee, C.-F. A neuro-fuzzy price forecasting approach in deregulated electricity markets. Electr. Power Syst. Res. 73, 151\u2013157 (2005).","journal-title":"Electr. Power Syst. Res."},{"key":"98839_CR33","doi-asserted-by":"crossref","unstructured":"Miles, J. R squared, adjusted r squared. Wiley StatsRef: Statistics Reference Online (2014).","DOI":"10.1002\/9781118445112.stat06627"},{"key":"98839_CR34","doi-asserted-by":"publisher","DOI":"10.1002\/9780470549148","volume-title":"Biomechanics and Motor Control of Human Movement","author":"DA Winter","year":"2009","unstructured":"Winter, D. A. Biomechanics and Motor Control of Human Movement (Wiley, 2009)."},{"key":"98839_CR35","doi-asserted-by":"publisher","first-page":"e0166815","DOI":"10.1371\/journal.pone.0166815","volume":"11","author":"CA R\u00e1bago","year":"2016","unstructured":"R\u00e1bago, C. A., Aldridge Whitehead, J. & Wilken, J. M. Evaluation of a powered ankle-foot prosthesis during slope ascent gait. PLoS One 11, e0166815 (2016).","journal-title":"PLoS One"},{"key":"98839_CR36","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/s12984-015-0014-8","volume":"12","author":"P Malcolm","year":"2015","unstructured":"Malcolm, P., Quesada, R. E., Caputo, J. M. & Collins, S. H. The influence of push-off timing in a robotic ankle-foot prosthesis on the energetics and mechanics of walking. J. Neuroeng. Rehabil. 12, 1\u201315 (2015).","journal-title":"J. Neuroeng. Rehabil."}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-021-98839-3.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-021-98839-3","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-021-98839-3.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,12,3]],"date-time":"2022-12-03T16:15:20Z","timestamp":1670084120000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-021-98839-3"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,10,5]]},"references-count":36,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2021,12]]}},"alternative-id":["98839"],"URL":"https:\/\/doi.org\/10.1038\/s41598-021-98839-3","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,10,5]]},"assertion":[{"value":"11 June 2021","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"6 September 2021","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"5 October 2021","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"The authors declare no competing interests.","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"19780"}}