The effects of common footwear on stance-phase mechanical properties of the prosthetic foot-shoe system

2017 ◽  
Vol 42 (2) ◽  
pp. 198-207 ◽  
Author(s):  
Matthew J Major ◽  
Joel Scham ◽  
Michael Orendurff
Keyword(s):  
Mechanical Properties ◽  
Repeated Measures ◽  
Clinical Relevance ◽  
Stance Phase ◽  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Test Machine ◽  
Mechanical Function ◽  
Prosthetic Foot ◽  
Prosthetic Feet

Background:Prosthetic feet are prescribed based on their mechanical function and user functional level. Subtle changes to the stiffness and hysteresis of heel, midfoot, and forefoot regions can influence the dynamics and economy of gait in prosthesis users. However, the user’s choice of shoes may alter the prosthetic foot-shoe system mechanical characteristics, compromising carefully prescribed and rigorously engineered performance of feet.Objectives:Observe the effects of footwear on the mechanical properties of the prosthetic foot-shoe system including commonly prescribed prosthetic feet.Study design:Repeated-measures, Mechanical characterization.Methods:The stiffness and energy return was measured using a hydraulic-driven materials test machine across combinations of five prosthetic feet and four common shoes as well as a barefoot condition.Results:Heel energy return decreased by an average 4%–9% across feet in all shoes compared to barefoot, with a cushioned trainer displaying the greatest effect. Foot designs that may improve perceived stability by providing low heel stiffness and rapid foot-flat were compromised by the addition of shoes.Conclusion:Shoes altered prosthesis mechanical characteristics in the sagittal and frontal planes, suggesting that shoe type should be controlled or reported in research comparing prostheses. Understanding of how different shoes could alter certain gait-related characteristics of prostheses may aid decisions on footwear made by clinicians and prosthesis users.Clinical relevanceShoes can alter function of the prosthetic foot-shoe system in unexpected and sometimes undesirable ways, often causing similar behavior across setups despite differences in foot design, and prescribing clinicians should carefully consider these effects on prosthesis performance.

Characterization of Medium Density Particleborads Using Agricultural Residues

2015 ◽  
Vol 1088 ◽  
pp. 656-659
Author(s):  
Ivaldo D. Valarelli ◽  
Rosane A.G. Battistelle ◽  
Barbara Stolte Bezerra ◽  
Luiz A. Melgaço N. Branco ◽  
Eduardo Chahud ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Castor Oil ◽  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Raw Materials ◽  
Construction Materials ◽  
Agricultural Residues ◽  
Medium Density ◽  
Polyurethane Resin

In recent years the production of products derived from wood and bamboo are increasing, due to the search for a more rational exploitation of these raw materials. Amongst these products, the particleboards production combine sustainability and rationality in the use of these materials. In this context, this work has the objective to study the application of alternative raw materials in the manufacture of Medium Density Particleboards (MDP), using residues from industrial processimg of coffee and bamboo. MDP had been produced with particles of giganteus bamboo of the Dendrocalamus species and particle of coffee rind in the intermediate layer of the particleboard, bonded with polyurethane resin based on castor oil. The physical and mechanical characterization was carried out accordingly to NBR 14810-3 (2006). The physical properties evaluated were: of water absorption for 2h and 24h; thickness swallowing for 2h and 24h; density, humidity content. The mechanical properties evaluated were: Tensile strength, static bending (MOR and MOE). The results were compared with NBR 14810-2 (2006) and also with the ANSI A208-1 (1993). The physical performance of these particleboards was below the values recommend by the Brazilian norm. Also the mechanical characteristics are not improve, demonstrating that the inclusion of coffee rind did not benefit the physical characteristics and nor the mechanical ones. However it can be used as construction materials for partitions and ceiling panels.

Parametric Evaluation of Hindfoot and Forefoot Properties and Their Effect on the Angular Stiffness of Prosthetic Feet

2012 ◽  
Author(s):  
Peter G. Adamczyk ◽  
Michelle Roland ◽  
Michael E. Hahn
Keyword(s):  
Stance Phase ◽  
Direct Calculation ◽  
Future Studies ◽  
Prosthetic Foot ◽  
Moment Arms ◽  
Walking Performance ◽  
Deformation Mechanics ◽  
Prosthetic Feet ◽  
Stiffness Characteristics ◽  
Parametric Adjustment

Prosthetic foot stiffness has been recognized as an important factor in optimizing the walking performance of amputees [1–3]. Commercial feet are available in a range of stiffness categories and geometries. The stiffness of linear displacements of the hindfoot and forefoot for several commercially available feet have been reported to be within a range of 27–68 N/mm [4] and 28–76 N/mm [5], respectively, but these values are most relevant only to the earliest and latest portions of stance phase, when linear compression or rebound naturally occur. In contrast, mid-stance kinetics are more related to the angular stiffness of the foot, which describes the ankle torque produced by angular progression of the lower limb over the foot during this phase. Little data is available regarding the angular stiffness of any commercially available feet. The variety of geometries between manufacturers and models of prosthetic feet makes a direct calculation of effective angular stiffness challenging due to changes in moment arms based on loading condition, intricacies of deformation mechanics of the structural components, and mechanical interaction between hindfoot and forefoot components. Thus, modeling the interaction between hindfoot stiffness, forefoot stiffness, and keel geometries and their combined effect on the angular stiffness of the foot may be a useful tool for correlating functional outcomes with stiffness characteristics of various feet. To understand how each of these factors affects angular stiffness, we developed a foot that can parametrically adjust each of these factors independently. The objective of this study was to mathematically model, design, and experimentally validate a prosthetic foot that has independent hindfoot and forefoot components, allowing for parametric adjustment of stiffness characteristics and keel geometry in future studies of amputee gait.

scholarly journals Development of a Mechatronic Platform and Validation of Methods for Estimating Ankle Stiffness During the Stance Phase of Walking

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Elliott J. Rouse ◽  
Levi J. Hargrove ◽  
Eric J. Perreault ◽  
Michael A. Peshkin ◽  
Todd A. Kuiken
Keyword(s):  
Mechanical Properties ◽  
Stance Phase ◽  
Testing Machine ◽  
Human Interaction ◽  
Joint Torque ◽  
Average Error ◽  
Prosthetic Foot ◽  
Ankle Impedance ◽  
Ankle Stiffness ◽  
Human Ankle

The mechanical properties of human joints (i.e., impedance) are constantly modulated to precisely govern human interaction with the environment. The estimation of these properties requires the displacement of the joint from its intended motion and a subsequent analysis to determine the relationship between the imposed perturbation and the resultant joint torque. There has been much investigation into the estimation of upper-extremity joint impedance during dynamic activities, yet the estimation of ankle impedance during walking has remained a challenge. This estimation is important for understanding how the mechanical properties of the human ankle are modulated during locomotion, and how those properties can be replicated in artificial prostheses designed to restore natural movement control. Here, we introduce a mechatronic platform designed to address the challenge of estimating the stiffness component of ankle impedance during walking, where stiffness denotes the static component of impedance. The system consists of a single degree of freedom mechatronic platform that is capable of perturbing the ankle during the stance phase of walking and measuring the response torque. Additionally, we estimate the platform's intrinsic inertial impedance using parallel linear filters and present a set of methods for estimating the impedance of the ankle from walking data. The methods were validated by comparing the experimentally determined estimates for the stiffness of a prosthetic foot to those measured from an independent testing machine. The parallel filters accurately estimated the mechatronic platform's inertial impedance, accounting for 96% of the variance, when averaged across channels and trials. Furthermore, our measurement system was found to yield reliable estimates of stiffness, which had an average error of only 5.4% (standard deviation: 0.7%) when measured at three time points within the stance phase of locomotion, and compared to the independently determined stiffness values of the prosthetic foot. The mechatronic system and methods proposed in this study are capable of accurately estimating ankle stiffness during the foot-flat region of stance phase. Future work will focus on the implementation of this validated system in estimating human ankle impedance during the stance phase of walking.

Influence of gait training and prosthetic foot category on external work symmetry during unilateral transtibial amputee gait

2013 ◽  
Vol 37 (5) ◽  
pp. 396-403 ◽  
Author(s):  
Vibhor Agrawal ◽  
Robert Gailey ◽  
Christopher O’Toole ◽  
Ignacio Gaunaurd ◽  
Adam Finnieston
Keyword(s):  
Repeated Measures ◽  
Gait Training ◽  
Third Party ◽  
External Work ◽  
Gait Dynamics ◽  
Prosthetic Foot ◽  
Negative Work ◽  
Level 3 ◽  
Prosthetic Feet ◽  
Level 2

Background:Prosthetic foot prescription guidelines lack scientific evidence and are concurrent with an amputee’s concurrent with an amputee’s Medicare Functional Classification Level (K-Level) and categorization of prosthetic feet.Objective:To evaluate the influence of gait training and four categories of prosthetic feet (K1, K2, K3, and microprocessor ankle/foot) on Symmetry in External Work for K-Level-2 and K-Level-3 unilateral transtibial amputees.Design:Randomized repeated-measures trial.Methods:Five K-Level-2 and five K-Level-3 subjects were tested in their existing prosthesis during Session 1 and again in Session 2, following 2 weeks of standardized gait training. In Sessions 3–6, subjects were tested using a study socket and one of four randomized test feet. There was an accommodation period of 10–14 days with each foot. Symmetry in External Work for positive and negative work was calculated at each session to determine symmetry of gait dynamics between limbs at self-selected walking speeds.Results:K-Level-2 subjects had significantly higher negative work symmetry with the K3 foot, compared to K1/K2 feet. For both subject groups, gait training had a greater impact on positive work symmetry than test feet.Conclusion:Higher work symmetry is possible for K-Level-2 amputees who are trained to take advantage of K3 prosthetic feet designs. There exists a need for an objective determinant for categorizing and prescribing prosthetic feet.Clinical relevanceFindings that gait training can influence symmetry of gait dynamics and that K-Level-2 amputees can achieve greater work symmetry with a K3 foot having a “J-shaped” ankle and heel-to-toe footplate could potentially impact prosthetic care and foot prescription by clinicians and reimbursement guidelines by third-party health-care payers.

Effect of Walking Speed on Angular Stiffness and Roll-Over Shape of the Intact and Prosthetic Feet of Transtibial Amputees

2013 ◽  
Author(s):  
Michelle Roland ◽  
Peter G. Adamczyk ◽  
Michael E. Hahn
Keyword(s):  
Lower Limb ◽  
Stance Phase ◽  
Walking Speed ◽  
Plantar Flexor ◽  
Limb Function ◽  
Prosthetic Foot ◽  
Material Stiffness ◽  
Prosthetic Feet ◽  
Transtibial Amputees ◽  
Lower Limb Function

The calculated roll-over shape and respective radius of intact and prosthetic feet has been shown to be a useful measure of lower limb function during walking [1–2]. Hansen et al [3] reported that the roll-over radius, R, is constant over a range of speeds for the intact foot-ankle system. It may be assumed that the prosthetic foot R would also be constant with increased walking speed. Similarly, the angular stiffness of prosthetic feet is not likely to change with walking speed, as the material stiffness remains unchanged. However, the effective angular stiffness of the intact ankle may increase with the plantar flexor moment during the stance phase of gait, which typically increases in magnitude with walking speed.

scholarly journals Development of Instrumented Running Prosthetic Feet for the Collection of Track Loads on Elite Athletes

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5758
Author(s):  
Nicola Petrone ◽  
Gianfabio Costa ◽  
Gianmario Foscan ◽  
Antonio Gri ◽  
Leonardo Mazzanti ◽  
...  
Keyword(s):  
Data Collection ◽  
Stance Phase ◽  
Elite Athletes ◽  
Calibration Procedure ◽  
Base Station ◽  
Ground Reaction Forces ◽  
Prosthetic Foot ◽  
Biomechanical Modelling ◽  
Reaction Forces ◽  
Prosthetic Feet

Knowledge of loads acting on running specific prostheses (RSP), and in particular on running prosthetic feet (RPF), is crucial for evaluating athletes’ technique, designing safe feet, and biomechanical modelling. The aim of this work was to develop a J-shaped and a C-shaped wearable instrumented running prosthetic foot (iRPF) starting from commercial RPF, suitable for load data collection on the track. The sensing elements are strain gauge bridges mounted on the foot in a configuration that allows decoupling loads parallel and normal to the socket-foot clamp during the stance phase. The system records data on lightweight athlete-worn loggers and transmits them via Wi-Fi to a base station for real-time monitoring. iRPF calibration procedure and static and dynamic validation of predicted ground-reaction forces against those measured by a force platform embedded in the track are reported. The potential application of this wearable system in estimating determinants of sprint performance is presented.

Patient evaluation of the Echelon foot using the Seattle Prosthesis Evaluation Questionnaire

2012 ◽  
Vol 37 (3) ◽  
pp. 250-254 ◽  
Author(s):  
Imad Sedki ◽  
Raymond Moore
Keyword(s):  
User Satisfaction ◽  
Clinical Relevance ◽  
Clinical Impact ◽  
Patient Evaluation ◽  
Case Description ◽  
Evaluation Questionnaire ◽  
Prosthetic Foot ◽  
Potential Benefits ◽  
Prosthetic Feet ◽  
Different Levels

Background: The introduction of the Echelon prosthetic foot with a hydraulic self-aligning ankle adds improved adaptability to varied terrains and uneven walking surfaces. However, the specific indications for prescribing such components and the potential benefits are yet to be fully established. Case Description and Methods: Nine amputees including three bilateral amputees evaluated their standard prostheses using the Seattle Prosthesis Evaluation Questionnaire. They were then provided with Echelon feet, and they evaluated them after 4 weeks of use. Findings and Outcomes: Improved satisfaction in all categories of use in relation to the Echelon foot with the greatest increase reported by bilateral amputees. Conclusion: The use of prosthetic feet with hydraulic self-aligning ankle improves prosthetic users’ satisfaction in general with a particular benefit in bilateral amputees. Clinical relevance Establish the clinical impact and user satisfaction after using Echelon feet in prosthetic users with different levels of amputations.

Development of a Bimodal Ankle-Foot Prosthesis for Walking and Standing/Swaying

2013 ◽  
Vol 7 (3) ◽  
Author(s):  
Andrew H. Hansen ◽  
Eric A. Nickel
Keyword(s):  
Mechanical Properties ◽  
Lower Limb ◽  
Mechanical Stability ◽  
Balance Confidence ◽  
Prosthetic Foot ◽  
Human Ankle ◽  
Body Center ◽  
Impaired Balance ◽  
Prosthetic Feet ◽  
Lower Height

The human ankle-foot system conforms to a circular effective rocker shape for walking, but to a much flatter effective shape for standing and swaying. Many persons with lower limb amputations have impaired balance and reduced balance confidence, and may benefit from prostheses designed to provide flatter effective rocker shapes during standing and swaying tasks. This paper describes the development and testing of an ankle-foot prosthesis prototype that provides distinctly different mechanical properties for walking and standing/swaying. The prototype developed was a single-axis prosthetic foot with a lockable ankle for added stability during standing and swaying. The bimodal ankle-foot prosthesis prototype was tested on pseudoprostheses (walking boots with prosthetic feet beneath) for walking and standing/swaying loads, and was compared to an Otto Bock single-axis prosthetic foot and to able-bodied data collected in a previous study. The height-normalized radius of the effective rocker shape for walking with the bimodal ankle-foot prototype was equal to that found earlier for able-bodied persons (0.17); the standing and swaying effective shape had a lower height-normalized radius (0.70) compared with that previously found for able-bodied persons (1.11). The bimodal ankle-foot prosthesis prototype had a similar radius as the Otto Bock single-axis prosthetic foot for the effective rocker shape for walking (0.17 for both), but had a much larger radius for standing and swaying (0.70 for bimodal, 0.34 for single-axis). The results suggest that the bimodal ankle-foot prosthesis prototype provides two distinct modes, including a biomimetic effective rocker shape for walking and an inherently stable base for standing and swaying. The radius of the prototype's effective rocker shape for standing/swaying suggests that it may provide inherent mechanical stability to a prosthesis user, since the radius is larger than the typical body center of mass’s distance from the floor (between 50–60% of height). Future testing is warranted to determine if the bimodal ankle-foot prosthesis will increase balance and balance confidence in prosthesis users.

Comparison of four different categories of prosthetic feet during ramp ambulation in unilateral transtibial amputees

2014 ◽  
Vol 39 (5) ◽  
pp. 380-389 ◽  
Author(s):  
Vibhor Agrawal ◽  
Robert S Gailey ◽  
Ignacio A Gaunaurd ◽  
Christopher O’Toole ◽  
Adam Finnieston ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Repeated Measures ◽  
Work Values ◽  
External Work ◽  
Higher Symmetry ◽  
Prosthetic Foot ◽  
Level 3 ◽  
Prosthetic Feet ◽  
Transtibial Amputees ◽  
Level 2

Background:Comparative effectiveness of prosthetic feet during ramp ambulation in unilateral transtibial amputees, who function at different Medicare Functional Classification Levels, has not been published.Objective:To determine differences in symmetry in external work between four categories of prosthetic feet in K-Level-2 and K-Level-3 unilateral transtibial amputees during ramp ascent and descent.Study design:Randomized repeated-measures trial.Methods:Ten subjects completed six testing sessions during which symmetry in external work was calculated using F-scan in-sole sensors. Between testing sessions 1 and 2, subjects received standardized functional prosthetic training. In Sessions 3–6, subjects tested four feet—solid ankle cushion heel, stationary attachment flexible endoskeleton, Talux (categories K1, K2, and K3, respectively), and Proprio-Foot (microprocessor ankle)—using a study socket and had a 10- to 14-day accommodation period with each foot.Results:During ramp descent, K-Level-2 subjects demonstrated higher symmetry in external work values with Talux and Proprio-Foot compared to the solid ankle cushion heel foot. K-Level-3 subjects also had higher symmetry in external work values with the Talux foot than the solid ankle cushion heel foot. Ramp ascent symmetry in external work values were not significantly different between feet.Conclusions:Prosthetic foot category appears to influence symmetry in external work more during decline walking than incline walking. K-Level-2 unilateral transtibial amputees achieve greater symmetry from K3 dynamic response prosthetic feet with J-shaped ankle and microprocessor ankles while descending ramps.Clinical relevanceThe findings suggest that K-Level-2 unilateral transtibial amputees benefit from K3 dynamic response prosthetic feet with J-shaped ankle. These results support the prescription of K3 feet for K-Level-2 amputees who frequently negotiate ramps.

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