中風後會造成許多後遺症。在這些後遺症當中，垂足會影響中風病人的步態控制、穩定性與行走表現。踝足矯正器(AFO)適用於中風患者。現今市售的儲能式的踝足矯正器不僅可以幫助患者解決垂足問題，還可以存儲和釋放更多能量。由於足底板的幾何形狀設計和材料，儲能式的矯正器可以存儲和釋放更多能量。此釋放的能量可以幫助中風病人推進。儲能式踝足矯正器有前緣翹起和足弓設計。當使用者在穿戴此種設計的踝足矯正器行走時，足底板會變形。此變形將導致踝足矯正器儲存能量。然而，現今研究較少討論對不同前緣翹起、足弓設計與材料的影響。本研究的目的是設計一根據市售儲能式踝足矯正器並具有不同的前緣翹起角度和不同足弓高度的儲能式矯正器。此外，本研究改變了足板的幾何形狀，以找到相對最佳的設計。
本研究使用SolidWorks 2016設計儲能式踝足矯正器（PH-AFO）的模型。本研究有三個參數: 前緣翹起角度、足弓高度與足底板材料。分別有五種不同的前緣翹起角度: 28.2o、 22.56o、 16.92o、 11.28o 與 5.64o。以及五種不同的足弓高度: 9.74mm、8.11mm、6.49mm、4.87mm與3.25mm。在本研究中使用兩種不同的材料: 鈦合金與碳纖維複合材料。本研究將PH-AFO模型導入ANSYS Workbench進行有限元素分析（FEA）。在有限元素分析中，本研究使用中風患者的數據來模擬中風患者的步態。
模擬結果顯示，有較高前緣翹起角度的PH-AFO存儲了更多的應變能。足弓高度對於儲能並沒有增加或減少的趨勢，但在最低足弓高度（3.25mm）有最大儲存的應變能。儲存於足弓的能量有助於病患提起腳跟。前緣翹起角度28.2o、足弓高度為3.25mm 的PH-AFO，材料為鈦合金，在模擬結果中存儲了最大應變能。此釋放的應變能量可以幫助患者推進。同時，此款矯正器在踝關節力矩貢獻最多。AFO釋放的能量越多，病患所需的力越少。Bregman等人製造碳纖維踝足矯正器（CFOs），以碳纖維彈簧連接小腿部件和足底板部件[51]。在他們的研究中，CFOs在踝關節力矩的貢獻率為52％; PH-AFO對踝關節力矩的貢獻率為鈦合金材料的43％，碳纖維複合材料的40％。CFOs的踝關節力矩貢獻主要來自於碳纖維彈簧的變形;而PH-AFO的踝關節力矩貢獻主要來自於足底板的變形。患者可以依自己的復健狀況選擇具有不同貢獻度的PH-AFO。未來的研究可以考慮將這兩個設計結合，以獲得更高的AFO貢獻率和儲存的能量。

Stroke may cause lots of sequelae. Among the sequelae, drop foot may influence the gait control, gait pattern, stability and working performance on people with stroke. Ankle-foot orthoses (AFOs) are usually prescribed for people with stroke. Currently, the commercially available power harvesting AFO could not only help patients solve the drop foot problem, but also store and release more energy than traditional AFO. This AFO could store and release more energy because of its geometry and material of the footplate. This energy restoration could help people with stroke propulsion. There are a frontal lift design and the arch design on power harvesting AFO. When people used AFO with these two designs during walking, the footplate would deform. And this deformation would help AFO store energy. However, there still few of studies discussed the effects on the different frontal lift angles and arch design. This study aims to design a AFO based on the commercially available power harvesting AFO with different frontal lift angles and different arch height in the footplate. In addition, this study changed the geometry of footplate to find the optimal design.
This study used SolidWorks 2016 to build the power harvesting AFO (PH-AFO) model. There are three parameters in this study including frontal lift angle, arch height and the materials of footplate. There are five different frontal lift angles including 28.2o, 22.56o, 16.92o, 11.28o and 5.64o. There are five different arch heights in this study including 9.74mm, 8.11mm, 6.49mm, 4.87mm and 3.25mm. Two different material which are titanium and carbon fiber composite were used in this study. This study imported the PH-AFO model into ANSYS Workbench to do the finite element analysis (FEA). In the FEA, data of stroke patients was used in this study to simulate the stroke patients’ gait.
PH-AFO with higher frontal lift angle stored more strain energy. There was no increased or decreased tendency as the arch height decreased in the strain energy result, but maximum strain energy occurred at lowest arch height (3.25mm). The energy stored in arch design might help patients do heel-off. PH-AFO with frontal lift angle 28.2o and arch height 3.25mm with the material of titanium stored the maximum strain energy in the simulation result. The return energy could assist the patient in push-off. PH-AFO with frontal lift angle 28.2o and arch height 3.25mm with the material of titanium also contributed most in ankle moment. The more energy released from AFO, the less effort patients make. Bregman et al. made a carbon fiber AFO (CFOs) with carbon fiber spring connecting the calf part and footplate part [51]. In their study, the percentage of CFOs contribution in ankle moment was 52%; while the percentage of PH-AFO contribution in ankle moment was 43% with the material of titanium and 40% with the material of carbon fiber composite. The contribution of CFOs came from the deformation of the carbon fiber spring; while the contribution of PH-AFO came from the deformation of the footplate. Patients could choose the AFO with different contribution depended on their own recovery progress. Future study might consider combine these two features together to get the higher AFO contribution and stored energy.

[1] 衛福部死因排行https://www.mohw.gov.tw/cp-16-41794-1.html
[2] B. Ahlsio, M. Britton, V. Murray, and T. Theorell, “Disablement and quality of life after stroke,” Stroke, vol. 15, pp. 886–890, 1984.
[3] J. Leung and A. Moseley, “Impact of ankle-foot orthoses on gait and leg muscle activity in adults with hemiplegia: Systematic literature review,” Physiotherapy, vol. 89, no. 1, pp. 39–55, 2003.
[4] M. Pohl and J. Mehrholz, "Immediate effects of an individually designed functional ankle-foot orthosis on stance and gait in hemiparetic patients." Clinical rehabilitation 20.4 (2006): 324-330.
[5] R. Y. Wang, Y. Lu, C. C. Lee, P. Y. Lin, M. F. Wang, Y. R. Yang. “Effects of an ankle-foot orthosis on balance performance in patients with hemiparesis of different durations,” Clin. Rehabil., 2005, 19(1), pp.37-44.
[6] C. D. Simons, E. H. van Asseldonk , H. van der Kooij, A.C. Geurts, J.H. Buurke, “Ankle-foot orthoses in stroke: effects on functional balance, weight-bearing asymmetry and the contribution of each lower limb to balance control”, Clin Biomech (Bristol, Avon), 2009 Nov, 24 (9), pp. 769-775.
[7] S. Brunnstrom, Movement Therapy in Hemiplegia. New York: Harper and Row, 1970.
[8] http://www.tma.tw/ltk/97510306.pdf
[9] FranceschiniM,MassucciM, Ferrari L, AgostiM, Paroli C. Effects of an ankle–foot orthosis on spatiotemporal parameters and energy cost of hemiparetic gait. Clin Rehabil 2003;17:368–72.
[10] J. Perry, Gait Analysis: Normal and Pathological Function. New York: McGraw-Hill, Inc., 1992.
[11] DeLisa, J.A. and Gans, B.M., “Physical Medicine & Rehabilitation: Principles and Practice”, ed. Lippincott Williams & Wilkins, 2005.
[12] T. F. Winters, J. G. Gage, and R. Hicks, “Gait patterns in spastic hemiplegia in children and young adults,” J. Joint Bone Surg., vol. 69A, pp. 437–441, 1987.
[13] J. M. Guralnik, L. Ferrucci, E. M. Simonsick, M. E. Salive, and R. B. Wallace, "Lower-extremity function in persons over the age of 70 years as a predictor of subsequent disability," N Engl J Med, vol. 332, pp. 556-61, Mar 2 1995.
[14] P. W. Duncan, K. J. Sullivan, A. L. Behrman, S. P. Azen, S. S. Wu, S. E. Nadeau, B. H. Dobkin, D. K. Rose, J. K. Tilson, and the LEAPS Investigative Team, "Protocol for the Locomotor Experience Applied Post-Stroke (LEAPS) trial: a randomized controlled trial," BMC Neurology, vol. 7, no. I, pp. 39, 2007.
[15] Olney, S. J., Griffin, M. P., & McBride, I. D. (1994). Temporal, kinematic, and kinetic variables related to gait speed in subjects with hemiplegia: a regression approach. Physical therapy, 74(9), 872-885.
[16] Ellis, R. G., Sumner, B. J., & Kram, R. (2014). Muscle contributions to propulsion and braking during walking and running: Insight from external force perturbations. Gait & Posture, 40(4), 594–599.
[17] S. B. O’Sullivan and T. J. Schmitz, Physical Rehabilitation, F.A. Davis Company, PA, USA, 2007.
[18] S. J. Olney, M. P. Griffin, and I. D. McBride, “Temporal, kinematic, and kinetic variables related to gait speed in subjects with hemiplegia: A regression approach,” Phys. Ther., vol. 74., pp. 872-885, 1994.
[19] Chung, Kyung Won (2005). Gross Anatomy (Board Review). Lippincott Williams & Wilkins.
[20] Chen C-C, Hong W-H, Wang C-M, Chen C-K, Wu K P-H, Kang C-F and Tang S F 2010 Kinematic features of rear-foot motion using anterior and posterior ankle-foot orthoses in stroke patients with hemiplegic gait Arch. Phys. Med. Rehabil. 91 1862–8
[21] C. Z. Ma, Y. P. Zheng, and W. C. Lee, “Changes in gait and plantar foot loading upon using vibrotactile wearable biofeedback system in patients with stroke,” Topics in Stroke Rehabilitation, vol. 25, no. 1, pp. 20–27, 2018.
[22] Lusardi, M. M., Jorge, M., & Nielsen, C. C. (2007). Orthotics and prosthetics in rehabilitation. 2nd ed.
219-36.
[23] Chang, J. J., & Lin, Y. T. (1993). A comparison of ankle fixation between two kinds of low-temperature plastic anterior ankle foot orthoses. Gaoxiong yi xue ke xue za zhi= The Kaohsiung journal of medical sciences, 9(10), 585-589.
[24] Wu, S. H. (1992). An anterior direct molding ankle-foot orthosis. 職能治療學會雜誌, 10, 75-81.
[25] Ryerson, S. D. (1988). The foot in hemiplegia. Physical Therapy of the Foot and Ankle. New York, NY: Churchill-Livingstone, 109-131.
[26] Pohl, M., & Mehrholz, J. (2006). Immediate effects of an individually designed functional ankle-foot orthosis on stance and gait in hemiparetic patients. Clinical rehabilitation, 20(4), 324-330.
[27] 鄭耕昊(2009)。低溫熱塑型前側式踝足副木之改良研究。國立陽明大學醫學工程研究所碩士論
文，未出版，台北。
[28] Park, J. H., Chun, M. H., Ahn, J. S., Yu, J. Y., & Kang, S. H. (2009). Comparison of gait analysis between anterior and posterior ankle foot orthosis in hemiplegic patients. American journal of physical medicine & rehabilitation, 88(8), 630-634.
[29] Chen, C. K., Hong, W. H., Chu, N. K., Lau, Y. C., Lew, H. L., & Tang, S. F. (2008). Effects of an anterior ankle–foot orthosis on postural stability in stroke patients with hemiplegia. American journal of physical medicine & rehabilitation, 87(10), 815-820.
[30] Ounpuu, S., Bell, K. J., Davis III, R. B., & DeLuca, P. A. (1996). An evaluation of the posterior leaf spring orthosis using joint kinematics and kinetics. Journal of Pediatric Orthopaedics, 16(3), 378-384.
[31] Allard AFO Professional Instructions: https://www.allardusa.com/foot-drop-afos/foot-drop-moderate-stability/toeoff-r-2-0-2.html
[32] Patient Foot Drop Brochure: https://www.allardusa.com/media/catalog/product/5638-patient-foot-drop-brochure.pdf
[33] Chu, T. M., Reddy, N. P., & Padovan, J. (1995). Three-dimensional finite element stress analysis of the polypropylene, ankle-foot orthosis: static analysis. Medical engineering & physics, 17(5), 372-379.
[34] Faustini, M. C., Neptune, R. R., Crawford, R. H., & Stanhope, S. J. (2008). Manufacture of passive dynamic ankle–foot orthoses using selective laser sintering. IEEE transactions on biomedical engineering, 55(2), 784-790.
[35] Banga, H. K., Belokar, R. M., Kalra, P., & Kumar, R. (2018). Fabrication and stress analysis of ankle foot orthosis with additive manufacturing. Rapid Prototyping Journal, 24(2), 301-312.
[36] Wu, P. Y. (2009). ToeOFF® The effectiveness of the ToeOFF® AFO in hemiplegic gait for CVA patients with flaccid ankle paralysis. Thesis of department of biomedical engineering, National Taiwan University. P1-65.
[37] Danielsson, A., & Sunnerhagen, K. S. (2004). Energy expenditure in stroke subjects walking with a carbon composite ankle foot orthosis. Journal of rehabilitation medicine, 36(4), 165-168.
[38] Ottobock. Orthopaedic Neurorehab, Available at: Accessed November 5, 2017.
http://www.ottobock.co.uk/.
[39] Alam, M., Choudhury, I. A., & Mamat, A. B. (2014). Mechanism and design analysis of articulated ankle foot orthoses for drop-foot. The Scientific World Journal, 2014.
[40] AFO dynamic https://www.ossur.com/injury-solutions/products/foot-and-ankle/ankle-foot-orthosis/afo-dynamic
[41] Wolf, S.I., Alimusaj, M., Rettig, O., Doderlein, L., 2008. Dynamic assist by carbon fiber spring AFOs for patients with myelomeningocele. Gait Posture 28, 175–177.
[42] Force plate formrlaehttps://isbweb.org/software/movanal/vaughan/kistler.pdf
[43] Plagenhoef, S., Evans, F.G. and Abdelnour, T., 1983. Anatomical data for analyzing human motion. Research quarterly for exercise and sport, 54(2), pp.169-178.
[44] T. G. McPoil et al., “Arch height change during sit-to-stand: an alternative for the navicular drop test,” Jour. of foot and ankle research, pp. vol. 3, 2009.
[45] Bartonek, A., Eriksson, M., Gutierrez-Farewik, E.M., 2007. A new carbon fibre spring
orthosis for children with plantarflexor weakness. Gait Posture 25, 652–656.
[46] Desloovere, K., Molenaers, G., Van, G.L., Huenaerts, C., Van, C.A., Callewaert, B., et al., 2006. How can push-off be preserved during use of an ankle foot orthosis in children with hemiplegia? A prospective controlled study. Gait Posture 24, 142–151.
[47] Wolf, S.I., Alimusaj, M., Rettig, O., Doderlein, L., 2008. Dynamic assist by carbon fiber spring AFOs for patients with myelomeningocele. Gait Posture 28, 175–177.
[48] Brehm M-A, Harlaar J, Schwartz M. Effect of Ankle-Foot Orthoses on Walking Efficiency and Gait in Children with Cerebral Palsy. Journal of Rehabilitation Medicine. // 2008;40(7):529-534.
[49] Mündermann, A., Stefanyshyn, D.J., Nigg, B.M., 2001. Relationship between footwear comfort of shoe inserts and anthropometric and sensory factors. Medic. Sci. Sports Exerc. 33, 1939–1945.
[50] Karimi, M. T., Fereshtehnejad, N. & Pool, F. The impact of foot insole on the energy consumption of flat-footed individuals during walking. Foot Ankle Spec 6, 21–26, doi: 10.1177/1938640012457676 (2013).
[51] D.J.J. Bregman, J. Harlaar, C.G.M. Meskers, V. de Groot, Spring-like Ankle Foot Orthoses reduce the energy cost of walking by taking over ankle work, Gait & Posture, 35(1), pp 148-153, Jan 2012.
[52] Pan W. F. (2008) Finite Element Analysis and Design on Ankle-Foot Orthosis. Essay of Department of Engineering Science, National Cheng Kung University
[53] Marques, M. A., Mendes, E., Ramos, N. V., Pinto, V. C., & Vaz, M. A. (2010). Finite-element analysis of ankle-foot orthosis to predict fracture conditions during gait. Proc. 1st ICH Gaia-Porto, Portugal.
[54] Wu, P. Y. (2009). ToeOFF® The effectiveness of the ToeOFF® AFO in hemiplegic gait for CVA patients with flaccid ankle paralysis. Thesis of department of biomedical engineering, National Taiwan University. P1-65
[55] Ma, X., & Luximon, A. (2013). Design and manufacture of shoe lasts. In Handbook of Footwear Design and Manufacture (pp. 177-196). Woodhead Publishing.
[56] YAMADA, T., MAIE, K., & KONDO, S. (1988). Shoes Last Design for Old Men to Improve Their Weak Acceleration during Walking. Journal of home economics of Japan, 39(6), 601-606.
[57] Williams, A. (2007). Footwear assessment and management. Podiatry management, 26(8), 165.
[58] Wiggin, M. B., Sawicki, G. S., & Collins, S. H. (2011, June). An exoskeleton using controlled energy storage and release to aid ankle propulsion. In 2011 IEEE International Conference on Rehabilitation Robotics (pp. 1-5). IEEE.
[59] Baraket, G., Chatti, K., Saddoud, O., Abdelkarim, A. B., Mars, M., Trifi, M., & Hannachi, A. S. (2011). Comparative assessment of SSR and AFLP markers for evaluation of genetic diversity and conservation of fig, Ficus carica L., genetic resources in Tunisia. Plant molecular biology reporter, 29(1), 171-184.