TPress
1.
Yazdani, M.; Hajiaghaei, B.; Saeedi, H.; Kamali, M.; Yousefi, M.
In: Curr. Orthop. Pract., Bd. 32, Nr. 5, S. 505–511, 2021, ISSN: 1940-7041.
Abstract | Links | Schlagwörter: adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test
@article{Yazdani2021,
title = {Does the socket design affect symmetry and spatiotemporal gait parameters? A case series of two transfemoral amputees},
author = {M. Yazdani and B. Hajiaghaei and H. Saeedi and M. Kamali and M. Yousefi},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L635549609&from=export},
doi = {10.1097/bco.0000000000001022},
issn = {1940-7041},
year = {2021},
date = {2021-01-01},
journal = {Curr. Orthop. Pract.},
volume = {32},
number = {5},
pages = {505–511},
address = {B. Hajiaghaei, Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Nezam Ave, Tehran, Iran},
abstract = {Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.},
keywords = {adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test},
pubstate = {published},
tppubtype = {article}
}
Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.
2.
Taboga, P.; Beck, O. N.; Grabowski, A. M.
In: PLoS ONE, Bd. 15, Nr. 2, 2020, ISSN: 1932-6203.
Abstract | Links | Schlagwörter: adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult
@article{Taboga2020,
title = {Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations},
author = {P. Taboga and O. N. Beck and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005026109&from=export},
doi = {10.1371/journal.pone.0229035},
issn = {1932-6203},
year = {2020},
date = {2020-01-01},
journal = {PLoS ONE},
volume = {15},
number = {2},
address = {P. Taboga, Department of Kinesiology, California State University, Sacramento, CA, United States},
abstract = {Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.},
keywords = {adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult},
pubstate = {published},
tppubtype = {article}
}
Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.
3.
Volkmar, R.; Dosen, S.; Gonzalez-Vargas, J.; Baum, M.; Markovic, M.
Improving bimanual interaction with a prosthesis using semi-autonomous control Artikel
In: J. NeuroEng. Rehabil., Bd. 16, Nr. 1, 2019, ISSN: 1743-0003.
Abstract | Links | Schlagwörter: adult, analytical equipment, article, bimanual interaction, controlled study, female, hand prosthesis, human, human experiment, inertial sensor, limb movement, male, motor control, motor performance, outcome assessment, priority journal, prosthesis, prosthesis design, semi autonomous control, sensor, task performance, vibrotactor, workload
@article{Volkmar2019,
title = {Improving bimanual interaction with a prosthesis using semi-autonomous control},
author = {R. Volkmar and S. Dosen and J. Gonzalez-Vargas and M. Baum and M. Markovic},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L629849607&from=export},
doi = {10.1186/s12984-019-0617-6},
issn = {1743-0003},
year = {2019},
date = {2019-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {16},
number = {1},
address = {M. Markovic, Department of Trauma Surgery Orthopedics and Plastic Surgery, University Medical Center Göttingen, Von-Siebold-Str. 3, Göttingen, Germany},
abstract = {Background: The loss of a hand is a traumatic experience that substantially compromises an individual's capability to interact with his environment. The myoelectric prostheses are state-of-the-art (SoA) functional replacements for the lost limbs. Their overall mechanical design and dexterity have improved over the last few decades, but the users have not been able to fully exploit these advances because of the lack of effective and intuitive control. Bimanual tasks are particularly challenging for an amputee since prosthesis control needs to be coordinated with the movement of the sound limb. So far, the bimanual activities have been often neglected by the prosthetic research community. Methods: We present a novel method to prosthesis control, which uses a semi-autonomous approach in order to simplify bimanual interactions. The approach supplements the commercial SoA two-channel myoelectric control with two additional sensors. Two inertial measurement units were attached to the prosthesis and the sound hand to detect the movement of both limbs. Once a bimanual interaction is detected, the system mimics the coordination strategies of able-bodied subjects to automatically adjust the prosthesis wrist rotation (pronation, supination) and grip type (lateral, palmar) to assist the sound hand during a bimanual task. The system has been evaluated in eight able-bodied subjects performing functional uni- A nd bi-manual tasks using the novel method and SoA two-channel myocontrol. The outcome measures were time to accomplish the task, semi-autonomous system misclassification rate, subjective rating of intuitiveness, and perceived workload (NASA TLX). Results: The results demonstrated that the novel control interface substantially outperformed the SoA myoelectric control. While using the semi-autonomous control the time to accomplish the task and the perceived workload decreased for 25 and 27%, respectively, while the subjects rated the system as more intuitive then SoA myocontrol. Conclusions: The novel system uses minimal additional hardware (two inertial sensors) and simple processing and it is therefore convenient for practical implementation. By using the proposed control scheme, the prosthesis assists the user's sound hand in performing bimanual interactions while decreasing cognitive burden.},
keywords = {adult, analytical equipment, article, bimanual interaction, controlled study, female, hand prosthesis, human, human experiment, inertial sensor, limb movement, male, motor control, motor performance, outcome assessment, priority journal, prosthesis, prosthesis design, semi autonomous control, sensor, task performance, vibrotactor, workload},
pubstate = {published},
tppubtype = {article}
}
Background: The loss of a hand is a traumatic experience that substantially compromises an individual's capability to interact with his environment. The myoelectric prostheses are state-of-the-art (SoA) functional replacements for the lost limbs. Their overall mechanical design and dexterity have improved over the last few decades, but the users have not been able to fully exploit these advances because of the lack of effective and intuitive control. Bimanual tasks are particularly challenging for an amputee since prosthesis control needs to be coordinated with the movement of the sound limb. So far, the bimanual activities have been often neglected by the prosthetic research community. Methods: We present a novel method to prosthesis control, which uses a semi-autonomous approach in order to simplify bimanual interactions. The approach supplements the commercial SoA two-channel myoelectric control with two additional sensors. Two inertial measurement units were attached to the prosthesis and the sound hand to detect the movement of both limbs. Once a bimanual interaction is detected, the system mimics the coordination strategies of able-bodied subjects to automatically adjust the prosthesis wrist rotation (pronation, supination) and grip type (lateral, palmar) to assist the sound hand during a bimanual task. The system has been evaluated in eight able-bodied subjects performing functional uni- A nd bi-manual tasks using the novel method and SoA two-channel myocontrol. The outcome measures were time to accomplish the task, semi-autonomous system misclassification rate, subjective rating of intuitiveness, and perceived workload (NASA TLX). Results: The results demonstrated that the novel control interface substantially outperformed the SoA myoelectric control. While using the semi-autonomous control the time to accomplish the task and the perceived workload decreased for 25 and 27%, respectively, while the subjects rated the system as more intuitive then SoA myocontrol. Conclusions: The novel system uses minimal additional hardware (two inertial sensors) and simple processing and it is therefore convenient for practical implementation. By using the proposed control scheme, the prosthesis assists the user's sound hand in performing bimanual interactions while decreasing cognitive burden.
4.
Beck, O. N.; Taboga, P.; Grabowski, A. M.
Characterizing the mechanical properties of running-specific prostheses Artikel
In: PLoS ONE, Bd. 11, Nr. 12, 2016, ISSN: 1932-6203.
Abstract | Links | Schlagwörter: 1E90 Sprinter, adult, amputation, article, athlete, body mass, Catapult FX6, Cheetah Xtend, clinical article, controlled study, female, Flex-Run, foot prosthesis, human, hysteresis, male, materials testing, mechanics, prosthesis design, prosthesis material, prosthetic force displacement, prosthetic height, prosthetic stiffness, running, running specific prosthesis, Sprinter, transtibial amputation
@article{Beck2016,
title = {Characterizing the mechanical properties of running-specific prostheses},
author = {O. N. Beck and P. Taboga and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L613668924&from=export},
doi = {10.1371/journal.pone.0168298},
issn = {1932-6203},
year = {2016},
date = {2016-01-01},
journal = {PLoS ONE},
volume = {11},
number = {12},
abstract = {The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.},
keywords = {1E90 Sprinter, adult, amputation, article, athlete, body mass, Catapult FX6, Cheetah Xtend, clinical article, controlled study, female, Flex-Run, foot prosthesis, human, hysteresis, male, materials testing, mechanics, prosthesis design, prosthesis material, prosthetic force displacement, prosthetic height, prosthetic stiffness, running, running specific prosthesis, Sprinter, transtibial amputation},
pubstate = {published},
tppubtype = {article}
}
The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.
2021
Yazdani, M.; Hajiaghaei, B.; Saeedi, H.; Kamali, M.; Yousefi, M.
In: Curr. Orthop. Pract., Bd. 32, Nr. 5, S. 505–511, 2021, ISSN: 1940-7041.
Abstract | Links | Schlagwörter: adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test
@article{Yazdani2021,
title = {Does the socket design affect symmetry and spatiotemporal gait parameters? A case series of two transfemoral amputees},
author = {M. Yazdani and B. Hajiaghaei and H. Saeedi and M. Kamali and M. Yousefi},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L635549609&from=export},
doi = {10.1097/bco.0000000000001022},
issn = {1940-7041},
year = {2021},
date = {2021-01-01},
journal = {Curr. Orthop. Pract.},
volume = {32},
number = {5},
pages = {505–511},
address = {B. Hajiaghaei, Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Nezam Ave, Tehran, Iran},
abstract = {Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.},
keywords = {adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test},
pubstate = {published},
tppubtype = {article}
}
Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.
2020
Taboga, P.; Beck, O. N.; Grabowski, A. M.
In: PLoS ONE, Bd. 15, Nr. 2, 2020, ISSN: 1932-6203.
Abstract | Links | Schlagwörter: adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult
@article{Taboga2020,
title = {Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations},
author = {P. Taboga and O. N. Beck and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005026109&from=export},
doi = {10.1371/journal.pone.0229035},
issn = {1932-6203},
year = {2020},
date = {2020-01-01},
journal = {PLoS ONE},
volume = {15},
number = {2},
address = {P. Taboga, Department of Kinesiology, California State University, Sacramento, CA, United States},
abstract = {Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.},
keywords = {adult, aerial time, article, athlete, below knee amputation, below knee prosthesis, biomechanics, clinical article, contact length, contact time, controlled study, Freedom Innovations Catapult FX6, ground reaction force, human, male, Ossur Flex-Foot Cheetah Xtend, Ottobock 1E90 Sprinter, physical parameters, prosthesis design, prosthetic height, prosthetic shape, prosthetic stiffness, running, running specific prosthesis, running speed, standing, vertical stiffness, young adult},
pubstate = {published},
tppubtype = {article}
}
Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.
2019
Volkmar, R.; Dosen, S.; Gonzalez-Vargas, J.; Baum, M.; Markovic, M.
Improving bimanual interaction with a prosthesis using semi-autonomous control Artikel
In: J. NeuroEng. Rehabil., Bd. 16, Nr. 1, 2019, ISSN: 1743-0003.
Abstract | Links | Schlagwörter: adult, analytical equipment, article, bimanual interaction, controlled study, female, hand prosthesis, human, human experiment, inertial sensor, limb movement, male, motor control, motor performance, outcome assessment, priority journal, prosthesis, prosthesis design, semi autonomous control, sensor, task performance, vibrotactor, workload
@article{Volkmar2019,
title = {Improving bimanual interaction with a prosthesis using semi-autonomous control},
author = {R. Volkmar and S. Dosen and J. Gonzalez-Vargas and M. Baum and M. Markovic},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L629849607&from=export},
doi = {10.1186/s12984-019-0617-6},
issn = {1743-0003},
year = {2019},
date = {2019-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {16},
number = {1},
address = {M. Markovic, Department of Trauma Surgery Orthopedics and Plastic Surgery, University Medical Center Göttingen, Von-Siebold-Str. 3, Göttingen, Germany},
abstract = {Background: The loss of a hand is a traumatic experience that substantially compromises an individual's capability to interact with his environment. The myoelectric prostheses are state-of-the-art (SoA) functional replacements for the lost limbs. Their overall mechanical design and dexterity have improved over the last few decades, but the users have not been able to fully exploit these advances because of the lack of effective and intuitive control. Bimanual tasks are particularly challenging for an amputee since prosthesis control needs to be coordinated with the movement of the sound limb. So far, the bimanual activities have been often neglected by the prosthetic research community. Methods: We present a novel method to prosthesis control, which uses a semi-autonomous approach in order to simplify bimanual interactions. The approach supplements the commercial SoA two-channel myoelectric control with two additional sensors. Two inertial measurement units were attached to the prosthesis and the sound hand to detect the movement of both limbs. Once a bimanual interaction is detected, the system mimics the coordination strategies of able-bodied subjects to automatically adjust the prosthesis wrist rotation (pronation, supination) and grip type (lateral, palmar) to assist the sound hand during a bimanual task. The system has been evaluated in eight able-bodied subjects performing functional uni- A nd bi-manual tasks using the novel method and SoA two-channel myocontrol. The outcome measures were time to accomplish the task, semi-autonomous system misclassification rate, subjective rating of intuitiveness, and perceived workload (NASA TLX). Results: The results demonstrated that the novel control interface substantially outperformed the SoA myoelectric control. While using the semi-autonomous control the time to accomplish the task and the perceived workload decreased for 25 and 27%, respectively, while the subjects rated the system as more intuitive then SoA myocontrol. Conclusions: The novel system uses minimal additional hardware (two inertial sensors) and simple processing and it is therefore convenient for practical implementation. By using the proposed control scheme, the prosthesis assists the user's sound hand in performing bimanual interactions while decreasing cognitive burden.},
keywords = {adult, analytical equipment, article, bimanual interaction, controlled study, female, hand prosthesis, human, human experiment, inertial sensor, limb movement, male, motor control, motor performance, outcome assessment, priority journal, prosthesis, prosthesis design, semi autonomous control, sensor, task performance, vibrotactor, workload},
pubstate = {published},
tppubtype = {article}
}
Background: The loss of a hand is a traumatic experience that substantially compromises an individual's capability to interact with his environment. The myoelectric prostheses are state-of-the-art (SoA) functional replacements for the lost limbs. Their overall mechanical design and dexterity have improved over the last few decades, but the users have not been able to fully exploit these advances because of the lack of effective and intuitive control. Bimanual tasks are particularly challenging for an amputee since prosthesis control needs to be coordinated with the movement of the sound limb. So far, the bimanual activities have been often neglected by the prosthetic research community. Methods: We present a novel method to prosthesis control, which uses a semi-autonomous approach in order to simplify bimanual interactions. The approach supplements the commercial SoA two-channel myoelectric control with two additional sensors. Two inertial measurement units were attached to the prosthesis and the sound hand to detect the movement of both limbs. Once a bimanual interaction is detected, the system mimics the coordination strategies of able-bodied subjects to automatically adjust the prosthesis wrist rotation (pronation, supination) and grip type (lateral, palmar) to assist the sound hand during a bimanual task. The system has been evaluated in eight able-bodied subjects performing functional uni- A nd bi-manual tasks using the novel method and SoA two-channel myocontrol. The outcome measures were time to accomplish the task, semi-autonomous system misclassification rate, subjective rating of intuitiveness, and perceived workload (NASA TLX). Results: The results demonstrated that the novel control interface substantially outperformed the SoA myoelectric control. While using the semi-autonomous control the time to accomplish the task and the perceived workload decreased for 25 and 27%, respectively, while the subjects rated the system as more intuitive then SoA myocontrol. Conclusions: The novel system uses minimal additional hardware (two inertial sensors) and simple processing and it is therefore convenient for practical implementation. By using the proposed control scheme, the prosthesis assists the user's sound hand in performing bimanual interactions while decreasing cognitive burden.
2016
Beck, O. N.; Taboga, P.; Grabowski, A. M.
Characterizing the mechanical properties of running-specific prostheses Artikel
In: PLoS ONE, Bd. 11, Nr. 12, 2016, ISSN: 1932-6203.
Abstract | Links | Schlagwörter: 1E90 Sprinter, adult, amputation, article, athlete, body mass, Catapult FX6, Cheetah Xtend, clinical article, controlled study, female, Flex-Run, foot prosthesis, human, hysteresis, male, materials testing, mechanics, prosthesis design, prosthesis material, prosthetic force displacement, prosthetic height, prosthetic stiffness, running, running specific prosthesis, Sprinter, transtibial amputation
@article{Beck2016,
title = {Characterizing the mechanical properties of running-specific prostheses},
author = {O. N. Beck and P. Taboga and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L613668924&from=export},
doi = {10.1371/journal.pone.0168298},
issn = {1932-6203},
year = {2016},
date = {2016-01-01},
journal = {PLoS ONE},
volume = {11},
number = {12},
abstract = {The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.},
keywords = {1E90 Sprinter, adult, amputation, article, athlete, body mass, Catapult FX6, Cheetah Xtend, clinical article, controlled study, female, Flex-Run, foot prosthesis, human, hysteresis, male, materials testing, mechanics, prosthesis design, prosthesis material, prosthetic force displacement, prosthetic height, prosthetic stiffness, running, running specific prosthesis, Sprinter, transtibial amputation},
pubstate = {published},
tppubtype = {article}
}
The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.
2021
Yazdani, M.; Hajiaghaei, B.; Saeedi, H.; Kamali, M.; Yousefi, M.
In: Curr. Orthop. Pract., Bd. 32, Nr. 5, S. 505–511, 2021, ISSN: 1940-7041.
@article{Yazdani2021,
title = {Does the socket design affect symmetry and spatiotemporal gait parameters? A case series of two transfemoral amputees},
author = {M. Yazdani and B. Hajiaghaei and H. Saeedi and M. Kamali and M. Yousefi},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L635549609&from=export},
doi = {10.1097/bco.0000000000001022},
issn = {1940-7041},
year = {2021},
date = {2021-01-01},
journal = {Curr. Orthop. Pract.},
volume = {32},
number = {5},
pages = {505–511},
address = {B. Hajiaghaei, Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Nezam Ave, Tehran, Iran},
abstract = {Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.
2020
Taboga, P.; Beck, O. N.; Grabowski, A. M.
In: PLoS ONE, Bd. 15, Nr. 2, 2020, ISSN: 1932-6203.
@article{Taboga2020,
title = {Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations},
author = {P. Taboga and O. N. Beck and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005026109&from=export},
doi = {10.1371/journal.pone.0229035},
issn = {1932-6203},
year = {2020},
date = {2020-01-01},
journal = {PLoS ONE},
volume = {15},
number = {2},
address = {P. Taboga, Department of Kinesiology, California State University, Sacramento, CA, United States},
abstract = {Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kNm-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.
2019
Volkmar, R.; Dosen, S.; Gonzalez-Vargas, J.; Baum, M.; Markovic, M.
Improving bimanual interaction with a prosthesis using semi-autonomous control Artikel
In: J. NeuroEng. Rehabil., Bd. 16, Nr. 1, 2019, ISSN: 1743-0003.
@article{Volkmar2019,
title = {Improving bimanual interaction with a prosthesis using semi-autonomous control},
author = {R. Volkmar and S. Dosen and J. Gonzalez-Vargas and M. Baum and M. Markovic},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L629849607&from=export},
doi = {10.1186/s12984-019-0617-6},
issn = {1743-0003},
year = {2019},
date = {2019-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {16},
number = {1},
address = {M. Markovic, Department of Trauma Surgery Orthopedics and Plastic Surgery, University Medical Center Göttingen, Von-Siebold-Str. 3, Göttingen, Germany},
abstract = {Background: The loss of a hand is a traumatic experience that substantially compromises an individual's capability to interact with his environment. The myoelectric prostheses are state-of-the-art (SoA) functional replacements for the lost limbs. Their overall mechanical design and dexterity have improved over the last few decades, but the users have not been able to fully exploit these advances because of the lack of effective and intuitive control. Bimanual tasks are particularly challenging for an amputee since prosthesis control needs to be coordinated with the movement of the sound limb. So far, the bimanual activities have been often neglected by the prosthetic research community. Methods: We present a novel method to prosthesis control, which uses a semi-autonomous approach in order to simplify bimanual interactions. The approach supplements the commercial SoA two-channel myoelectric control with two additional sensors. Two inertial measurement units were attached to the prosthesis and the sound hand to detect the movement of both limbs. Once a bimanual interaction is detected, the system mimics the coordination strategies of able-bodied subjects to automatically adjust the prosthesis wrist rotation (pronation, supination) and grip type (lateral, palmar) to assist the sound hand during a bimanual task. The system has been evaluated in eight able-bodied subjects performing functional uni- A nd bi-manual tasks using the novel method and SoA two-channel myocontrol. The outcome measures were time to accomplish the task, semi-autonomous system misclassification rate, subjective rating of intuitiveness, and perceived workload (NASA TLX). Results: The results demonstrated that the novel control interface substantially outperformed the SoA myoelectric control. While using the semi-autonomous control the time to accomplish the task and the perceived workload decreased for 25 and 27%, respectively, while the subjects rated the system as more intuitive then SoA myocontrol. Conclusions: The novel system uses minimal additional hardware (two inertial sensors) and simple processing and it is therefore convenient for practical implementation. By using the proposed control scheme, the prosthesis assists the user's sound hand in performing bimanual interactions while decreasing cognitive burden.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: The loss of a hand is a traumatic experience that substantially compromises an individual's capability to interact with his environment. The myoelectric prostheses are state-of-the-art (SoA) functional replacements for the lost limbs. Their overall mechanical design and dexterity have improved over the last few decades, but the users have not been able to fully exploit these advances because of the lack of effective and intuitive control. Bimanual tasks are particularly challenging for an amputee since prosthesis control needs to be coordinated with the movement of the sound limb. So far, the bimanual activities have been often neglected by the prosthetic research community. Methods: We present a novel method to prosthesis control, which uses a semi-autonomous approach in order to simplify bimanual interactions. The approach supplements the commercial SoA two-channel myoelectric control with two additional sensors. Two inertial measurement units were attached to the prosthesis and the sound hand to detect the movement of both limbs. Once a bimanual interaction is detected, the system mimics the coordination strategies of able-bodied subjects to automatically adjust the prosthesis wrist rotation (pronation, supination) and grip type (lateral, palmar) to assist the sound hand during a bimanual task. The system has been evaluated in eight able-bodied subjects performing functional uni- A nd bi-manual tasks using the novel method and SoA two-channel myocontrol. The outcome measures were time to accomplish the task, semi-autonomous system misclassification rate, subjective rating of intuitiveness, and perceived workload (NASA TLX). Results: The results demonstrated that the novel control interface substantially outperformed the SoA myoelectric control. While using the semi-autonomous control the time to accomplish the task and the perceived workload decreased for 25 and 27%, respectively, while the subjects rated the system as more intuitive then SoA myocontrol. Conclusions: The novel system uses minimal additional hardware (two inertial sensors) and simple processing and it is therefore convenient for practical implementation. By using the proposed control scheme, the prosthesis assists the user's sound hand in performing bimanual interactions while decreasing cognitive burden.
2016
Beck, O. N.; Taboga, P.; Grabowski, A. M.
Characterizing the mechanical properties of running-specific prostheses Artikel
In: PLoS ONE, Bd. 11, Nr. 12, 2016, ISSN: 1932-6203.
@article{Beck2016,
title = {Characterizing the mechanical properties of running-specific prostheses},
author = {O. N. Beck and P. Taboga and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L613668924&from=export},
doi = {10.1371/journal.pone.0168298},
issn = {1932-6203},
year = {2016},
date = {2016-01-01},
journal = {PLoS ONE},
volume = {11},
number = {12},
abstract = {The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.