Kinetic Differences in a Subject With Two Different Prosthetic Knees While Performing Sitting and Standing Movements

2008 ◽  
Author(s):  
Derek J. Lura ◽  
M. Jason Highsmith ◽  
Stephanie L. Carey ◽  
Rajiv V. Dubey
Keyword(s):  
Control Subject ◽  
Lower Limb ◽  
Gait Cycle ◽  
Knee Prosthesis ◽  
Large Population ◽  
Human Locomotion ◽  
Ongoing Study ◽  
Consumer Markets ◽  
The Difference ◽  
Prosthetic Knees

Advanced prostheses are currently being sold in consumer markets. The development of these advanced prostheses is largely a result of a better understanding of the biomechanics of human locomotion [1]. Powered and microprocessor controlled prostheses are offering better performance in a variety of movements and in the gait cycle. However the focus in lower limb prosthetics has been largely on locomotion (e.g. walking, stair gait and running). This study focuses on the sit and stand cycles of an individual with an Otto Bock C-leg and an Ossur Power Knee prosthesis, comparing his ability to utilize each prosthesis and comparing his cycle to that of a healthy (non-amputee) control subject. This study is part of a larger ongoing study of the sit and stand cycles seen in a large population of unilateral transfemoral prosthetic users of various kinds. The purpose of this study is to compare the difference in method of standing, and assistance provided by the prosthesis. With the knowledge gained from this study we hope to better understand the biomechanics of the sit and stand cycles, leading to better prostheses in the future.

scholarly journals Mechanics and energetics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

2020 ◽  
Author(s):  
Richard W. Nuckols ◽  
Kota Z. Takahashi ◽  
Dominic J. Farris ◽  
Sarai Mizrachi ◽  
Raziel Riemer ◽  
...  
Keyword(s):  
Lower Limb ◽  
Gait Cycle ◽  
Human Locomotion ◽  
Mechanical Power ◽  
Joint Mechanics ◽  
Wearable Robot ◽  
Lower Limb Exoskeleton ◽  
Surface Gradient ◽  
Gait Phase ◽  
Robotic Devices

AbstractLower-limb wearable robotic devices can provide effective assistance to both clinical and healthy populations; however, how assistance should be applied in different gait conditions and environments is still unclear. We suggest a biologically-inspired approach derived from knowledge of human locomotion mechanics and energetics to establish a ‘roadmap’ for wearable robot design. In this study, we characterize the changes in joint mechanics during both walking and running across a range of incline/decline grades and then provide an analysis that informs the development of lower-limb exoskeletons capable of operating across a range of mechanical demands. Eight subjects (6M,2F) completed five walking (1.25 m -1) trials at −15%, −10%, 0%, 10%, and 15% grade and five running (2.25 m s-1) trials at −10%, −5%, 0%, 5%, and 10% grade on a treadmill. We calculated time-varying joint moment and power output for the ankle, knee, and hip. For each gait, we examined how individual limb-joints contributed to total limb positive, negative and net power across grades. For both walking and running, changes in grade caused a redistribution of joint mechanical power generation and absorption. From level to incline walking, the ankle’s contribution to limb positive power decreased from 44% on the level to 28% at 15% uphill grade (p < 0.0001) while the hip’s contribution increased from 27% to 52% (p < 0.0001). In running, regardless of the surface gradient, the ankle was consistently the dominant source of lower-limb positive mechanical power (47-55%). In the context of our results, we outline three distinct use-modes that could be emphasized in future lower-limb exoskeleton designs 1) Energy injection: adding positive work into the gait cycle, 2) Energy extraction: removing negative work from the gait cycle, and 3) Energy transfer: extracting energy in one gait phase and then injecting it in another phase (i.e., regenerative braking).

Timing-Specific Transfer of Adapted Muscle Activity After Walking in an Elastic Force Field

2009 ◽  
Vol 102 (1) ◽  
pp. 568-577 ◽  
Author(s):  
Andreanne Blanchette ◽  
Laurent J. Bouyer
Keyword(s):  
Force Field ◽  
Lower Limb ◽  
Neural Control ◽  
Gait Cycle ◽  
Human Locomotion ◽  
Emg Activity ◽  
Field Exposure ◽  
Limb Kinematics ◽  
Increased Activity ◽  
Lower Limb Kinematics

Human locomotion results from interactions between feedforward (central commands from voluntary and automatic drive) and feedback (peripheral commands from sensory inputs) mechanisms. Recent studies have shown that locomotion can be adapted when an external force is applied to the lower limb. To better understand the neural control of this adaptation, the present study investigated gait modifications resulting from exposure to a position-dependent force field. Ten subjects walked on a treadmill before, during, and after exposure to a force field generated by elastic tubing that pulled the foot forward and up during swing. Lower limb kinematics and electromyographic (EMG) activity were recorded during each walking period. During force field exposure, peak foot velocity was initially increased by 38%. As subjects adapted, peak foot velocity gradually returned to baseline in ≤125 strides. In the adapted state, hamstring EMG activity started earlier (16% before toe off) and remained elevated throughout swing. After force field exposure, foot velocity was initially reduced by 22% and returned to baseline in 9–51 strides. Aftereffects in hamstring EMGs consisted of increased activity around toe off. Contrary to the adapted state, this increase was not maintained during the rest of swing. Together, these results suggest that while the neural control of human locomotion can adapt to force field exposure, the mechanisms underlying this adaptation may vary according to the timing in the gait cycle. Adapted hamstring EMG activity may rely more on feedforward mechanisms around toe off and more on feedback mechanisms during the rest of swing.

scholarly journals A comparison of the SACH and single axis foot in the gait of unilateral below-knee amputees

1983 ◽  
Vol 7 (1) ◽  
pp. 33-36 ◽  
Author(s):  
N. E. Doane ◽  
L. E. Holt
Keyword(s):  
Lower Limb ◽  
Gait Cycle ◽  
Knee Prosthesis ◽  
Statistical Significance ◽  
Swing Phase ◽  
Joint Angles ◽  
Gait Patterns ◽  
Prosthetic Devices ◽  
Prosthetic Limb ◽  
Points Of View

The gait patterns of unilateral below-knee amputees wearing prostheses with either a SACH foot or a single axis foot were compared. A temporary below-knee prosthesis was fabricated for each subject using plaster of Paris and Plastazote for the socket, a pylon and an artificial foot. Eight subjects were filmed at two separate sessions, one in which the SACH foot was worn on their prosthesis and one with the single axis foot on their prosthesis. Measurements of the normal leg with a SACH foot on the prosthetic limb were compared to measurements of the normal leg with a single axis foot on the prosthesis. Measurements of the prosthetic leg with both devices were also compared. A one tailed t test (p<.05) was used to determine statistical significance of the results obtained in six measurements of lower limb joint angles and on the percentage of the time of gait cycle for stance and swing phase of the prosthetic leg. Discussion centres on the interpretation of the results from both statistical and clinical points of view. Major differences (excepting the ankle at foot-flat) between the prosthetic devices were not found.

scholarly journals Analysis of Friction in Total Knee Prosthesis during a Standard Gait Cycle

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 36
Author(s):  
Matúš Ranuša ◽  
Markus A. Wimmer ◽  
Spencer Fullam ◽  
Martin Vrbka ◽  
Ivan Křupka
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Computational Models ◽  
Gait Cycle ◽  
Knee Prosthesis ◽  
Shear Stresses ◽  
Cobalt Chromium ◽  
Joint Friction ◽  
The Coefficient Of Friction ◽  
Total Knee

Total knee arthroplasty is on the rise worldwide. Despite its success, revision surgeries are also increasing. According to the American Joint Replacement Registry 2020, 3.3% of revision surgeries are due to wear, and 24.2% are due to mechanical loosening. The combination of shear stresses and wear particles occurring at the bone/implant interface can lead to local osteolysis. Although the shear stresses are partially driven by joint friction, relatively little is known about the evolution of the coefficient of friction (CoF) during a gait cycle in total knee replacement. Here we describe the CoF during a gait cycle and investigate its association with kinematics (slide–roll-ratio), applied load, and relative velocity. The artificial knee was simulated by cobalt–chromium condyle on a flat ultra-high-molecular-weight polyethylene (UHMWPE) tibial plateau, lubricated by either water or proteinaceous solution. We found that the CoF is not a constant but fluctuates between the values close to 0 and 0.15. Cross-correlation suggested that this is primarily an effect of the slide–roll ratio and the contact pressure. There was no difference in the CoF between water and proteinaceous solution. Knowledge about the CoF behavior during a gait cycle will help to increase the accuracy of future computational models of total knee replacement.

Novel active magnetorheological knee prosthesis presents low energy consumption during ground walking

2021 ◽  
pp. 1045389X2098392
Author(s):  
Rafhael Milanezi de Andrade ◽  
Jordana Simões Ribeiro Martins ◽  
Marcos Pinotti ◽  
Antônio Bento Filho ◽  
Claysson Bruno Santos Vimieiro
Keyword(s):  
Energy Consumption ◽  
Stance Phase ◽  
Gait Cycle ◽  
Dynamic Models ◽  
Knee Prosthesis ◽  
Regenerative Braking ◽  
Harmonic Drive ◽  
Low Energy Consumption ◽  
Energetic Expenditure ◽  
Over Ground Walking

This study analyses the energy consumption of an active magnetorheological knee (AMRK) actuator that was designed for transfemoral prostheses. The system was developed as an operational motor unit (MU), which consists of an EC motor, a harmonic drive and a magnetorheological (MR) clutch, that operates in parallel with an MR brake. The dynamic models of the MR brake and MU were used to simulate the system’s energetic expenditure during over-ground walking under three different working conditions: using the complete AMRK; using just its motor-reducer, to operate as a common active knee prosthesis (CAKP), and using just the MR brake, to operate as a common semi-active knee prosthesis (CSAKP). The results are used to compare the MR devices power consumptions with that of the motor-reducer. As previously hypothesized, to use the MR brake in the swing phase is more energetically efficient than using the motor-reducer to drive the joint. Even if using the motor-reducer in regenerative braking mode during the stance phase, the differences in power consumption among the systems are remarkable. The AMRK expended 16.3 J during a gait cycle, which was 1.6 times less than the energy expenditure of the CAKP (26.6 J), whereas the CSAKP required just 6.0 J.

Reduced cortical brain activity with the use of microprocessor-controlled prosthetic knees during walking

2018 ◽  
Vol 43 (3) ◽  
pp. 257-265 ◽  
Author(s):  
Saffran Möller ◽  
David Rusaw ◽  
Kerstin Hagberg ◽  
Nerrolyn Ramstrand
Keyword(s):  
Cognitive Processes ◽  
Lower Limb ◽  
Brain Activity ◽  
Control Group ◽  
Healthy Controls ◽  
Prosthetic Knee ◽  
Level Walking ◽  
Lower Limb Prosthesis ◽  
Prosthetic Knees ◽  
Limb Prosthesis

Background: Individuals using a lower-limb prosthesis indicate that they need to concentrate on every step they take. Despite self-reports of increased cognitive demand, there is limited understanding of the link between cognitive processes and walking when using a lower-limb prosthesis. Objective: The objective was to assess cortical brain activity during level walking in individuals using different prosthetic knee components and compare them to healthy controls. It was hypothesized that the least activity would be observed in the healthy control group, followed by individuals using a microprocessor-controlled prosthetic knee and finally individuals using a non-microprocessor-controlled prosthetic knee. Study design: Cross-sectional study. Methods: An optical brain imaging system was used to measure relative changes in concentration of oxygenated and de-oxygenated haemoglobin in the frontal and motor cortices during level walking. The number of steps and time to walk 10 m was also recorded. The 6-min walk test was assessed as a measure of functional capacity. Results: Individuals with a transfemoral or knee-disarticulation amputation, using non-microprocessor-controlled prosthetic knee ( n = 14) or microprocessor-controlled prosthetic knee ( n = 15) joints and healthy controls ( n = 16) participated in the study. A significant increase was observed in cortical brain activity of individuals walking with a non-microprocessor-controlled prosthetic knee when compared to healthy controls ( p < 0.05) and individuals walking with an microprocessor-controlled prosthetic knee joint ( p < 0.05). Conclusion: Individuals walking with a non-microprocessor-controlled prosthetic knee demonstrated an increase in cortical brain activity compared to healthy individuals. Use of a microprocessor-controlled prosthetic knee was associated with less cortical brain activity than use of a non-microprocessor-controlled prosthetic knee. Clinical relevance Increased understanding of cognitive processes underlying walking when using different types of prosthetic knees can help to optimize selection of prosthetic components and provide an opportunity to enhance functioning with a prosthesis.

scholarly journals Posture, Flexibility and Grip Strength in Horse Riders

2014 ◽  
Vol 42 (1) ◽  
pp. 113-125 ◽  
Author(s):  
Sarah Jane Hobbs ◽  
Joanna Baxter ◽  
Louise Broom ◽  
Laura-Ann Rossell ◽  
Jonathan Sinclair ◽  
...  
Keyword(s):  
Grip Strength ◽  
Chronic Back Pain ◽  
Large Population ◽  
Functional Asymmetry ◽  
Leg Length ◽  
Sitting Posture ◽  
Competition Level ◽  
Negative Trait ◽  
The Difference ◽  
The Uk

Abstract Since the ability to train the horse to be ambidextrous is considered highly desirable, rider asymmetry is recognized as a negative trait. Acquired postural and functional asymmetry can originate from numerous anatomical regions, so it is difficult to suggest if any is developed due to riding. The aim of this study was therefore to assess symmetry of posture, strength and flexibility in a large population of riders and to determine whether typical traits exist due to riding. 127 right handed riders from the UK and USA were categorized according to years riding (in 20 year increments) and their competition level (using affiliated test levels). Leg length, grip strength and spinal posture were measured and recorded by a physiotherapist. Standing and sitting posture and trunk flexibility were measured with 3-D motion capture technology. Right-left differences were explored in relation to years riding and rider competitive experience. Significant anatomical asymmetry was found for the difference in standing acromion process height for a competition level (-0.07±1.50 cm Intro/Prelim; 0.02±1.31 cm Novice; 0.43±1.27 cm Elementary+; p=0.048) and for sitting iliac crest height for years riding (-0.23±1.36 cm Intro/Prelim; 0.01±1.50 cm Novice; 0.86±0.41 cm Elementary+; p=0.021). For functional asymmetry, a significant interaction was found for lateral bending ROM for years riding x competition level (p=0.047). The demands on dressage riders competing at higher levels may predispose these riders to a higher risk of developing asymmetry and potentially chronic back pain rather than improving their symmetry

scholarly journals Automatic Incremental Learning of Terrain Transitions in a Powered Below Knee Prosthesis

2020 ◽  
Author(s):  
Roman Stolyarov ◽  
Hugh Herr ◽  
Matt Carney
Keyword(s):  
Lower Limb ◽  
Incremental Learning ◽  
Prediction Accuracy ◽  
Knee Prosthesis ◽  
Estimation Algorithm ◽  
Limited Sample ◽  
Physiological Conditions ◽  
Lower Limb Prosthesis ◽  
Limb Prosthesis ◽  
High Range

Objective: This paper describes the developmentand preliminary offline validation of an algorithm facilitatingautomatic, self-contained learning of ground terrain transitionsin a lower limb prosthesis. This method allows for continuous,in-field convergence on an optimal terrain prediction accuracyfor a given walking condition, and is thus not limited bythe specific conditions and limited sample size of an in-labtraining scheme. Methods: We asked one subject with a below-kneeamputation to traverse level ground, stairs, and rampsusing a high-range-of-motion powered prosthesis while internalsensor data were remotely logged. We then used these datato develop a dynamic classification algorithm which predictsthe terrain of each stride and then continuously updates thepredictor using both data from the previous stride and anaccurate terrain back-estimation algorithm. Results: Across 100simulations randomizing stride order, our method attained amean next-stride prediction accuracy of ? 96%. This valuewas first reached after ? 200 strides, or about ? 5 minutesof walking. Conclusion and significance: These results demonstratea method for automatically learning the gait patternspreceding terrain transitions in a prosthesis without relyingon any external devices. By virtue of its dynamic learningscheme, application of this method in real-time would allow forcontinuous, in-field optimization of prediction accuracy across avariety of walking variables including physiological conditions,variable terrain geometries, control methodologies, and users.

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