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Bo K Foreman - One of the best experts on this subject based on the ideXlab platform.
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contribution of Ankle Foot Orthosis moment in regulating Ankle and knee motions during gait in individuals post stroke
Clinical Biomechanics, 2017Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Bo K ForemanAbstract:Abstract Background Ankle-Foot Orthosis moment resisting plantarflexion has systematic effects on Ankle and knee joint motion in individuals post-stroke. However, it is not known how much Ankle-Foot Orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated Ankle-Foot Orthosis moment to regulate Ankle and knee joint motion during gait in individuals post-stroke. Methods Gait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated Ankle-Foot Orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-Foot Orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the Ankle-Foot Orthosis around the Ankle joint measured by bench testing. The Ankle-Foot Orthosis moment and the joint angular position (Ankle and knee) relationship in a gait cycle was plotted to quantify the Ankle-Foot Orthosis moment needed to regulate the joint motion. Findings Ankle and knee joint motion were regulated according to the amount of Ankle-Foot Orthosis moment during gait. The Ankle-Foot Orthosis maintained the Ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from − 0.029 (0.011) to − 0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative). Interpretations Quantifying the contribution of Ankle-Foot Orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an Ankle-Foot Orthosis for individuals post-stroke.
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reduction of genu recurvatum through adjustment of plantarflexion resistance of an articulated Ankle Foot Orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-Foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistance of an articulated Ankle-Foot Orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated Ankle-Foot Orthosis whose plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four plantarflexion resistance conditions of the Ankle-Foot Orthosis. Gait parameters included: a) peak Ankle plantarflexion angle, b) peak Ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of plantarflexion resistance of the Ankle-Foot Orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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the effect of changing plantarflexion resistive moment of an articulated Ankle Foot Orthosis on Ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of plantarflexion resistive moment of an articulated Ankle–Foot Orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis on Ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated Ankle–Foot Orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The Ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the Ankle–Foot Orthosis. Increasing the plantarflexion resistive moment of the Ankle–Foot Orthosis induced significant decreases both in the peak Ankle plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated Ankle–Foot Orthosis for improved orthotic care in individual patients.
Toshiki Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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The effects of an articulated Ankle-Foot Orthosis with resistance-adjustable joints on lower limb joint kinematics and kinetics during gait in individuals post-stroke.
Clinical Biomechanics, 2018Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Lucas S. Lincoln, Grace Hunt, Nicholas Lecursi, K. Bo ForemanAbstract:Abstract Background Resistance is a key mechanical property of an Ankle-Foot Orthosis that affects gait in individuals post-stroke. Triple Action® joints allow independent adjustment of plantarflexion resistance and dorsiflexion resistance of an Ankle-Foot Orthosis. Therefore, the aim of this study was to investigate the effects of incremental changes in dorsiflexion and plantarflexion resistance of an articulated Ankle-Foot Orthosis with the Triple Action joints on lower limb joint kinematics and kinetics in individuals post-stroke during gait. Methods Gait analysis was performed on 10 individuals who were post-stroke under eight resistance settings (four plantarflexion and four dorsiflexion resistances) using the articulated Ankle-Foot Orthosis. Kinematic and kinetic data of the lower limb joints were recorded while walking using a three-dimensional Vicon motion capture system and a Bertec split-belt instrumented treadmill. Findings Repeated measures analysis of variance revealed that adjustment of plantarflexion resistance had significant main effects on the Ankle (P Interpretation This study demonstrated that the adjustments of resistance in the Ankle-Foot Orthosis with the Triple Action joints influenced Ankle and knee kinematics in individuals post-stroke. Further work is necessary to investigate the long-term effects of the articulated Ankle-Foot orthoses on their gait.
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contribution of Ankle Foot Orthosis moment in regulating Ankle and knee motions during gait in individuals post stroke
Clinical Biomechanics, 2017Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Bo K ForemanAbstract:Abstract Background Ankle-Foot Orthosis moment resisting plantarflexion has systematic effects on Ankle and knee joint motion in individuals post-stroke. However, it is not known how much Ankle-Foot Orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated Ankle-Foot Orthosis moment to regulate Ankle and knee joint motion during gait in individuals post-stroke. Methods Gait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated Ankle-Foot Orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-Foot Orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the Ankle-Foot Orthosis around the Ankle joint measured by bench testing. The Ankle-Foot Orthosis moment and the joint angular position (Ankle and knee) relationship in a gait cycle was plotted to quantify the Ankle-Foot Orthosis moment needed to regulate the joint motion. Findings Ankle and knee joint motion were regulated according to the amount of Ankle-Foot Orthosis moment during gait. The Ankle-Foot Orthosis maintained the Ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from − 0.029 (0.011) to − 0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative). Interpretations Quantifying the contribution of Ankle-Foot Orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an Ankle-Foot Orthosis for individuals post-stroke.
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reduction of genu recurvatum through adjustment of plantarflexion resistance of an articulated Ankle Foot Orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-Foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistance of an articulated Ankle-Foot Orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated Ankle-Foot Orthosis whose plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four plantarflexion resistance conditions of the Ankle-Foot Orthosis. Gait parameters included: a) peak Ankle plantarflexion angle, b) peak Ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of plantarflexion resistance of the Ankle-Foot Orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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Direct measurement of plantarflexion resistive moments and angular positions of an articulated Ankle–Foot Orthosis while walking in individuals post stroke: A preliminary study
Journal of rehabilitation and assistive technologies engineering, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Lucas S. Lincoln, K. Bo ForemanAbstract:: The plantarflexion resistive moments of an articulated Ankle-Foot Orthosis play an important role in improving gait in individuals post stroke. However, the evidence regarding their magnitude required from the articulated Ankle-Foot Orthosis to improve walking is still limited. Therefore, the primary aim of this study was to directly measure the plantarflexion resistive moments and the joint angular positions while walking using a prototype instrumented articulated Ankle-Foot Orthosis in five individuals post stroke. The secondary aim was to investigate their moment-angle relationship by changing its preset plantarflexion stiffness. Each subject was fitted with the instrumented articulated Ankle-Foot Orthosis and walked on a treadmill under four different preset plantarflexion stiffness conditions (0.35 N·m/°, 0.51 N·m/°, 0.87 N·m/°, and 1.27 N·m/°). For each subject, the plantarflexion resistive moments and the joint angular positions of five continuous gait cycles were extracted and averaged for each condition. Data were plotted and presented as case series. Both plantarflexion resistive moments and joint angular positions of the Ankle-Foot Orthosis changed according to the preset plantarflexion stiffness in all subjects. Using the instrumented articulated Ankle-Foot Orthosis could potentially advance the understanding of the biomechanics of an Ankle-Foot Orthosis, as well as contribute to more evidence-based orthotic care of patients.
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the effect of changing plantarflexion resistive moment of an articulated Ankle Foot Orthosis on Ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of plantarflexion resistive moment of an articulated Ankle–Foot Orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis on Ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated Ankle–Foot Orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The Ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the Ankle–Foot Orthosis. Increasing the plantarflexion resistive moment of the Ankle–Foot Orthosis induced significant decreases both in the peak Ankle plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated Ankle–Foot Orthosis for improved orthotic care in individual patients.
Michael S Orendurff - One of the best experts on this subject based on the ideXlab platform.
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The effects of an articulated Ankle-Foot Orthosis with resistance-adjustable joints on lower limb joint kinematics and kinetics during gait in individuals post-stroke.
Clinical Biomechanics, 2018Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Lucas S. Lincoln, Grace Hunt, Nicholas Lecursi, K. Bo ForemanAbstract:Abstract Background Resistance is a key mechanical property of an Ankle-Foot Orthosis that affects gait in individuals post-stroke. Triple Action® joints allow independent adjustment of plantarflexion resistance and dorsiflexion resistance of an Ankle-Foot Orthosis. Therefore, the aim of this study was to investigate the effects of incremental changes in dorsiflexion and plantarflexion resistance of an articulated Ankle-Foot Orthosis with the Triple Action joints on lower limb joint kinematics and kinetics in individuals post-stroke during gait. Methods Gait analysis was performed on 10 individuals who were post-stroke under eight resistance settings (four plantarflexion and four dorsiflexion resistances) using the articulated Ankle-Foot Orthosis. Kinematic and kinetic data of the lower limb joints were recorded while walking using a three-dimensional Vicon motion capture system and a Bertec split-belt instrumented treadmill. Findings Repeated measures analysis of variance revealed that adjustment of plantarflexion resistance had significant main effects on the Ankle (P Interpretation This study demonstrated that the adjustments of resistance in the Ankle-Foot Orthosis with the Triple Action joints influenced Ankle and knee kinematics in individuals post-stroke. Further work is necessary to investigate the long-term effects of the articulated Ankle-Foot orthoses on their gait.
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contribution of Ankle Foot Orthosis moment in regulating Ankle and knee motions during gait in individuals post stroke
Clinical Biomechanics, 2017Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Bo K ForemanAbstract:Abstract Background Ankle-Foot Orthosis moment resisting plantarflexion has systematic effects on Ankle and knee joint motion in individuals post-stroke. However, it is not known how much Ankle-Foot Orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated Ankle-Foot Orthosis moment to regulate Ankle and knee joint motion during gait in individuals post-stroke. Methods Gait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated Ankle-Foot Orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-Foot Orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the Ankle-Foot Orthosis around the Ankle joint measured by bench testing. The Ankle-Foot Orthosis moment and the joint angular position (Ankle and knee) relationship in a gait cycle was plotted to quantify the Ankle-Foot Orthosis moment needed to regulate the joint motion. Findings Ankle and knee joint motion were regulated according to the amount of Ankle-Foot Orthosis moment during gait. The Ankle-Foot Orthosis maintained the Ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from − 0.029 (0.011) to − 0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative). Interpretations Quantifying the contribution of Ankle-Foot Orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an Ankle-Foot Orthosis for individuals post-stroke.
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reduction of genu recurvatum through adjustment of plantarflexion resistance of an articulated Ankle Foot Orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-Foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistance of an articulated Ankle-Foot Orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated Ankle-Foot Orthosis whose plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four plantarflexion resistance conditions of the Ankle-Foot Orthosis. Gait parameters included: a) peak Ankle plantarflexion angle, b) peak Ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of plantarflexion resistance of the Ankle-Foot Orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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Direct measurement of plantarflexion resistive moments and angular positions of an articulated Ankle–Foot Orthosis while walking in individuals post stroke: A preliminary study
Journal of rehabilitation and assistive technologies engineering, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Lucas S. Lincoln, K. Bo ForemanAbstract:: The plantarflexion resistive moments of an articulated Ankle-Foot Orthosis play an important role in improving gait in individuals post stroke. However, the evidence regarding their magnitude required from the articulated Ankle-Foot Orthosis to improve walking is still limited. Therefore, the primary aim of this study was to directly measure the plantarflexion resistive moments and the joint angular positions while walking using a prototype instrumented articulated Ankle-Foot Orthosis in five individuals post stroke. The secondary aim was to investigate their moment-angle relationship by changing its preset plantarflexion stiffness. Each subject was fitted with the instrumented articulated Ankle-Foot Orthosis and walked on a treadmill under four different preset plantarflexion stiffness conditions (0.35 N·m/°, 0.51 N·m/°, 0.87 N·m/°, and 1.27 N·m/°). For each subject, the plantarflexion resistive moments and the joint angular positions of five continuous gait cycles were extracted and averaged for each condition. Data were plotted and presented as case series. Both plantarflexion resistive moments and joint angular positions of the Ankle-Foot Orthosis changed according to the preset plantarflexion stiffness in all subjects. Using the instrumented articulated Ankle-Foot Orthosis could potentially advance the understanding of the biomechanics of an Ankle-Foot Orthosis, as well as contribute to more evidence-based orthotic care of patients.
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the effect of changing plantarflexion resistive moment of an articulated Ankle Foot Orthosis on Ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of plantarflexion resistive moment of an articulated Ankle–Foot Orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis on Ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated Ankle–Foot Orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The Ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the Ankle–Foot Orthosis. Increasing the plantarflexion resistive moment of the Ankle–Foot Orthosis induced significant decreases both in the peak Ankle plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated Ankle–Foot Orthosis for improved orthotic care in individual patients.
Madeline L Singer - One of the best experts on this subject based on the ideXlab platform.
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contribution of Ankle Foot Orthosis moment in regulating Ankle and knee motions during gait in individuals post stroke
Clinical Biomechanics, 2017Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Bo K ForemanAbstract:Abstract Background Ankle-Foot Orthosis moment resisting plantarflexion has systematic effects on Ankle and knee joint motion in individuals post-stroke. However, it is not known how much Ankle-Foot Orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated Ankle-Foot Orthosis moment to regulate Ankle and knee joint motion during gait in individuals post-stroke. Methods Gait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated Ankle-Foot Orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-Foot Orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the Ankle-Foot Orthosis around the Ankle joint measured by bench testing. The Ankle-Foot Orthosis moment and the joint angular position (Ankle and knee) relationship in a gait cycle was plotted to quantify the Ankle-Foot Orthosis moment needed to regulate the joint motion. Findings Ankle and knee joint motion were regulated according to the amount of Ankle-Foot Orthosis moment during gait. The Ankle-Foot Orthosis maintained the Ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from − 0.029 (0.011) to − 0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative). Interpretations Quantifying the contribution of Ankle-Foot Orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an Ankle-Foot Orthosis for individuals post-stroke.
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reduction of genu recurvatum through adjustment of plantarflexion resistance of an articulated Ankle Foot Orthosis in individuals post stroke
Clinical Biomechanics, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background Genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke. Ankle-Foot orthoses are used to improve genu recurvatum, but evidence is limited concerning their effectiveness. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistance of an articulated Ankle-Foot Orthosis on genu recurvatum in patients post-stroke. Methods Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated Ankle-Foot Orthosis whose plantarflexion resistance was adjustable at four levels. Gait data were collected using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Gait parameters were extracted and plotted for each subject under the four plantarflexion resistance conditions of the Ankle-Foot Orthosis. Gait parameters included: a) peak Ankle plantarflexion angle, b) peak Ankle dorsiflexion moment, c) peak knee extension angle and d) peak knee flexion moment. A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses. Findings All the gait parameters demonstrated statistically significant differences among the four resistance conditions of the AFO. Increasing the amount of plantarflexion resistance of the Ankle-Foot Orthosis generally reduced genu recurvatum in all subjects. However, individual analyses showed that the responses to the changes in the plantarflexion resistance of the AFO were not necessarily linear, and appear unique to each subject. Interpretations The plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke. Future studies should investigate what clinical factors would influence the individual differences.
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Direct measurement of plantarflexion resistive moments and angular positions of an articulated Ankle–Foot Orthosis while walking in individuals post stroke: A preliminary study
Journal of rehabilitation and assistive technologies engineering, 2016Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Lucas S. Lincoln, K. Bo ForemanAbstract:: The plantarflexion resistive moments of an articulated Ankle-Foot Orthosis play an important role in improving gait in individuals post stroke. However, the evidence regarding their magnitude required from the articulated Ankle-Foot Orthosis to improve walking is still limited. Therefore, the primary aim of this study was to directly measure the plantarflexion resistive moments and the joint angular positions while walking using a prototype instrumented articulated Ankle-Foot Orthosis in five individuals post stroke. The secondary aim was to investigate their moment-angle relationship by changing its preset plantarflexion stiffness. Each subject was fitted with the instrumented articulated Ankle-Foot Orthosis and walked on a treadmill under four different preset plantarflexion stiffness conditions (0.35 N·m/°, 0.51 N·m/°, 0.87 N·m/°, and 1.27 N·m/°). For each subject, the plantarflexion resistive moments and the joint angular positions of five continuous gait cycles were extracted and averaged for each condition. Data were plotted and presented as case series. Both plantarflexion resistive moments and joint angular positions of the Ankle-Foot Orthosis changed according to the preset plantarflexion stiffness in all subjects. Using the instrumented articulated Ankle-Foot Orthosis could potentially advance the understanding of the biomechanics of an Ankle-Foot Orthosis, as well as contribute to more evidence-based orthotic care of patients.
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the effect of changing plantarflexion resistive moment of an articulated Ankle Foot Orthosis on Ankle and knee joint angles and moments while walking in patients post stroke
Clinical Biomechanics, 2015Co-Authors: Toshiki Kobayashi, Michael S Orendurff, Madeline L Singer, Wayne K Daly, Bo K ForemanAbstract:Abstract Background The adjustment of plantarflexion resistive moment of an articulated Ankle–Foot Orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis on Ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated Ankle–Foot Orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The Ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the Ankle–Foot Orthosis. Increasing the plantarflexion resistive moment of the Ankle–Foot Orthosis induced significant decreases both in the peak Ankle plantarflexion angle (P Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated Ankle–Foot Orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated Ankle–Foot Orthosis for improved orthotic care in individual patients.
William K. Durfee - One of the best experts on this subject based on the ideXlab platform.
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The Application of Series Elastic Actuators in the Hydraulic Ankle-Foot Orthosis
2018 Design of Medical Devices Conference, 2018Co-Authors: William K. DurfeeAbstract:Advances in Ankle-Foot Orthosis (AFO) technology have been trending toward more powerful and lightweight devices. A hydraulic series elastic actuator (HSEA) was explored to design a lightweight powered AFO that meets the high peak power demand of Ankle gait. With its excellent power density and its ability to separate the power supply from the actuator using a hose, hydraulic power was used, combined with an SEA that takes advantage of the high-peak and low-average power profile of Ankle gait to store energy and release it during the push-off stage of gait. The parameters required for the SEA were determined and validated using simulation. A gait pattern that would require 235W of motor power was able to be tracked using a motor rated at 95W. The actuator weight of the hydraulic Ankle-Foot Orthosis (HAFO) at the Ankle was 0.35, which is 43% of an equivalent electromechanical system. A novel design of an HSEA with a clutch capability is proposed for future HAFO applications.Copyright © 2018 by ASME
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Simulation Based Design of a Pediatric-Sized Hydraulic Ankle-Foot Orthosis
Volume 2: Mechatronics; Mechatronics and Controls in Advanced Manufacturing; Modeling and Control of Automotive Systems and Combustion Engines; Modeli, 2016Co-Authors: Brett Cullen Neubauer, William K. DurfeeAbstract:Cerebral palsy can cause gait impairments in children that require the prescription of passive Ankle-Foot orthoses. This project aims to develop a pediatric-sized hydraulic active Ankle-Foot Orthosis with computer-controlled stiffness. The Orthosis will allow a clinician to investigate a range of AFO stiffnesses while collecting gait performance metrics to determine the optimal stiffness value for the AFO prescription. The Ankle-Foot Orthosis uses hydraulic technology to generate the large required torques in a light, compact package. The preliminary design uses additive manufacturing to further reduce the weight of the manifolds on the medial and lateral sides of the Ankle. The simulation prototype of the design illustrated that the Orthosis should be capable of generating 91 Nm of Ankle torque and a maximum angular velocity of 483 °/sec. The device will be a valuable resource in the clinic, saving time and resources in the AFO prescription process while improving the healthcare of the patient.
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Design of a portable hydraulic Ankle-Foot Orthosis
2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2014Co-Authors: Brett Cullen Neubauer, Jonathan Nath, William K. DurfeeAbstract:Small-scale hydraulics is ideal for powered human assistive devices including powered Ankle Foot orthoses because a large torque can be generated with an actuator that is small and light. A portable hydraulic Ankle Foot Orthosis has been designed and is undergoing preliminary prototyping and engineering bench test evaluation. The device provides 90 Nm of Ankle torque and has an operating pressure of 138 bar (2,000 psi). The battery-operated hydraulic power supply weighs about 3 kg and is worn at the waist. The Ankle component weighs about 1.2 Kg and connects to the power supply with two hoses. Performance simulation and preliminary bench testing suggests that the device could be useful in certain rehabilitation applications.
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Portable Pneumatically-Powered Ankle-Foot Orthosis
Journal of Medical Devices-transactions of The Asme, 2012Co-Authors: Elizabeth T. Hsiao-wecksler, K. Alex Shorter, Yifan Li, Geza F. Kogler, William K. DurfeeAbstract:The goal of this work is to address challenges with developing and utilizing mobile powered orthotic devices or exoskeletons, especially those that depend on miniature pneumatic power systems. We present an ongoing research testbed to explore hardware and software solutions related to effective, efficient control and operation of such devices. The testbed platform is a pneumatically-powered Ankle-Foot Orthosis that can provide bidirectional (dorsiflexor, plantarflexor) torque. A mobile pneumatic power source can be used to examine issues related to providing gait assistance in a variety of environments beyond walking on a treadmill or confined level-ground space. We refer to this platform as the Portable Powered Ankle-Foot Orthosis (PPAFO) (Fig. 1) [1].