Design and Fabrication of an Elastic Knee Orthosis: Preliminary Results

2006 ◽  
Author(s):  
Michael S. Cherry ◽  
Dave J. Choi ◽  
Kevin J. Deng ◽  
Sridhar Kota ◽  
Daniel P. Ferris
Keyword(s):  
Mechanical Design ◽  
Human Subjects ◽  
Metabolic Cost ◽  
Knee Brace ◽  
Ongoing Research ◽  
Ankle Stiffness ◽  
Neuromuscular Response ◽  
Compliant Surfaces ◽  
Stiff Spring ◽  
Knee Orthosis

When humans hop or run on compliant surfaces they alter the stiffness of their legs so that the overall stiffness of the leg-surface system remains the same. Adding a spring in parallel to the ankle joint incites a similar neuromuscular response; humans decrease their biological ankle stiffness such that the overall ankle stiffness remains unchanged. These results suggest that an elastic exoskeleton could be effective at reducing the metabolic cost of locomotion. To further increase our understanding of human response we have developed an elastic knee brace that adds a stiff spring in parallel to the knee. It will be used as a test platform in ascertaining the neuromuscular effects of adding a parallel knee spring while hopping on one leg. This paper focuses primarily on the mechanical design and implementation of our elastic knee orthosis. Results of the forthcoming studies of human subjects wearing this knee orthosis will be presented in a separate article that will focus on the biomechanics and the neuromuscular adaptations of the human body. Prior research found that the neuromuscular response to hopping on compliant surfaces was the same when running on compliant surfaces. We expect that our results from hopping with springs in parallel with the knee will also be applicable to running. This elastic knee brace represents the first phase of an ongoing research project to develop a passive compliant lower-body exoskeleton to assist in human running. It is expected that this research will benefit healthy individuals as well as those with disabilities causing decreased muscle function.

scholarly journals The principles of medical ethics and medical research

1999 ◽  
Vol 15 (suppl 1) ◽  
pp. S7-S13 ◽  
Author(s):  
John Harris
Keyword(s):  
Public Health ◽  
Medical Ethics ◽  
Medical Research ◽  
Late Onset ◽  
Human Subjects ◽  
Predictive Testing ◽  
Public Health Issue ◽  
Public Health Medicine ◽  
International Ethics ◽  
Ongoing Research

In this paper I discuss the application of the principles of medical ethics and of medical research to the case of children and others whose consent to treatment and to research is problematic. Public health depends substantially on the possibility of ongoing research into all conditions which affect the health of the people. Constraints on this research are therefore a public health issue. Moreover and more importantly the possibility of predictive testing and indeed of screening for health-relevant conditions is an important public health tool, and limitations on the use of this tool are of great significance to public health medicine. Having considered the particular problems created by research and predictive testing on children for late-onset conditions I go on to discuss research on those whose consent is problematic more generally. I conclude with radical recommendations for the reform of The Declaration of Helsinki and of the International Ethics Guidelines for Biomedical Research Involving Human Subjects, prepared by the Council for International Organizations of Medical Sciences (CIOMS).

scholarly journals Cardiac Telocytes 16 Years on—What Have We Learned So Far, and How Close Are We to Routine Application of the Knowledge in Cardiovascular Regenerative Medicine?

2021 ◽  
Vol 22 (20) ◽  
pp. 10942
Author(s):  
Martin Klein ◽  
Mária Csöbönyeiová ◽  
Stanislav Žiaran ◽  
Ľuboš Danišovič ◽  
Ivan Varga
Keyword(s):  
Myocardial Infarction ◽  
Stem Cell ◽  
Cell Therapy ◽  
Human Subjects ◽  
Research Area ◽  
Future Research ◽  
Ongoing Research ◽  
Routine Application ◽  
Cardiovascular Regeneration ◽  
A Cell

The regeneration of a diseased heart is one of the principal challenges of modern cardiovascular medicine. There has been ongoing research on stem-cell-based therapeutic approaches. A cell population called telocytes (TCs) described only 16 years ago largely contributed to the research area of cardiovascular regeneration. TCs are cells with small bodies and extremely long cytoplasmic projections called telopodes, described in all layers of the heart wall. Their functions include cell-to-cell signaling, stem-cell nursing, mechanical support, and immunoregulation, to name but a few. The functional derangement or quantitative loss of TCs has been implicated in the pathogenesis of myocardial infarction, heart failure, arrhythmias, and many other conditions. The exact pathomechanisms are still unknown, but the loss of regulative, integrative, and nursing functions of TCs may provide important clues. Therefore, a viable avenue in the future modern management of these conditions is TC-based cell therapy. TCs have been previously transplanted into a mouse model of myocardial infarction with promising results. Tandem transplantation with stem cells may provide additional benefit; however, many underresearched areas need to be addressed in future research before routine application of TC-based cell therapy in human subjects. These include the standardization of protocols for isolation, cultivation, and transplantation, quantitative optimization of TC transplants, cost-effectivity analysis, and many others.

scholarly journals The effects of ankle stiffness on mechanics and energetics of walking with added loads: a prosthetic emulator study

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Erica A. Hedrick ◽  
Philippe Malcolm ◽  
Jason M. Wilken ◽  
Kota Z. Takahashi
Keyword(s):  
Energy Cost ◽  
Load Condition ◽  
Metabolic Cost ◽  
Load Carriage ◽  
Metabolic Energy ◽  
Additional Load ◽  
Ankle Stiffness ◽  
Human Ankle ◽  
Positive Work ◽  
Load Conditions

Abstract Background The human ankle joint has an influential role in the regulation of the mechanics and energetics of gait. The human ankle can modulate its joint ‘quasi-stiffness’ (ratio of plantarflexion moment to dorsiflexion displacement) in response to various locomotor tasks (e.g., load carriage). However, the direct effect of ankle stiffness on metabolic energy cost during various tasks is not fully understood. The purpose of this study was to determine how net metabolic energy cost was affected by ankle stiffness while walking under different force demands (i.e., with and without additional load). Methods Individuals simulated an amputation by using an immobilizer boot with a robotic ankle-foot prosthesis emulator. The prosthetic emulator was controlled to follow five ankle stiffness conditions, based on literature values of human ankle quasi-stiffness. Individuals walked with these five ankle stiffness settings, with and without carrying additional load of approximately 30% of body mass (i.e., ten total trials). Results Within the range of stiffness we tested, the highest stiffness minimized metabolic cost for both load conditions, including a ~ 3% decrease in metabolic cost for an increase in stiffness of about 0.0480 Nm/deg/kg during normal (no load) walking. Furthermore, the highest stiffness produced the least amount of prosthetic ankle-foot positive work, with a difference of ~ 0.04 J/kg from the highest to lowest stiffness condition. Ipsilateral hip positive work did not significantly change across the no load condition but was minimized at the highest stiffness for the additional load conditions. For the additional load conditions, the hip work followed a similar trend as the metabolic cost, suggesting that reducing positive hip work can lower metabolic cost. Conclusion While ankle stiffness affected the metabolic cost for both load conditions, we found no significant interaction effect between stiffness and load. This may suggest that the importance of the human ankle’s ability to change stiffness during different load carrying tasks may not be driven to minimize metabolic cost. A prosthetic design that can modulate ankle stiffness when transitioning from one locomotor task to another could be valuable, but its importance likely involves factors beyond optimizing metabolic cost.

Neuromechanical adaptation to hopping with an elastic ankle-foot orthosis

2006 ◽  
Vol 100 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Daniel P. Ferris ◽  
Zaineb A. Bohra ◽  
Jamie R. Lukos ◽  
Catherine R. Kinnaird
Keyword(s):  
Muscle Activation ◽  
Human Subjects ◽  
Medial Gastrocnemius ◽  
Lateral Gastrocnemius ◽  
Ankle Foot Orthosis ◽  
Ankle Stiffness ◽  
Surface Stiffness ◽  
Stiffness Constant ◽  
Leg Stiffness ◽  
Foot Orthosis

When humans hop or run on different surfaces, they adjust their effective leg stiffness to offset changes in surface stiffness. As a result, the overall stiffness of the leg-surface series combination remains independent of surface stiffness. The purpose of this study was to determine whether humans make a similar adjustment when springs are placed in parallel with the leg via a lower limb orthosis. We studied seven human subjects hopping in place on one leg while wearing an ankle-foot orthosis. We used an ankle-foot orthosis because the ankle joint is primarily responsible for leg stiffness during hopping. A spring was added to the ankle-foot orthosis so that it increased orthosis stiffness by providing plantar flexor torque during ankle dorsiflexion. We hypothesized that subjects would decrease their biological ankle stiffness when the spring was added to the orthosis, keeping total ankle stiffness constant. We collected kinematic, kinetic, and electromyographic data during hopping with and without the spring on the orthosis. We found that total ankle stiffness and leg stiffness did not change across the two orthosis conditions (ANOVA, P > 0.05). This was possible because subjects decreased their biological ankle stiffness to offset the orthosis spring stiffness ( P < 0.0001). The reduction in biological ankle stiffness was accompanied by decreases in soleus, medial gastrocnemius, and lateral gastrocnemius muscle activation ( P < 0.0002). These results suggest that an elastic exoskeleton might improve human running performance by reducing muscle recruitment.

Consumer Opinions of a Stance Control Knee Orthosis

2006 ◽  
Vol 30 (3) ◽  
pp. 246-256 ◽  
Author(s):  
Kathie A. Bernhardt ◽  
Steven E. Irby ◽  
Kenton R. Kaufman
Keyword(s):  
Field Trial ◽  
Positive Experience ◽  
Knee Brace ◽  
System A ◽  
Stance Control ◽  
Control Knee ◽  
Knee Orthosis

Stance control knee orthoses (SCOs) have become very popular recently. However, there is little information regarding opinions of actual orthosis users. The purpose of this study was to quantify the users' opinions of a SCO, and see whether factors found important for knee orthoses in past studies hold true for a stance control orthosis as well. A standardized survey was employed as part of a larger field trial study of the Dynamic Knee Brace System, a SCO developed by the authors. The Dynamic Knee Brace System scored well in areas of effectiveness, operability, and dependability, but areas in need of improvement included weight, cosmesis, and donning and doffing. These findings match well with previous knee orthosis studies. This study shows that wearing a stance control knee orthosis can be a positive experience for an orthosis user.

Energetics and mechanics of human running on surfaces of different stiffnesses

2002 ◽  
Vol 92 (2) ◽  
pp. 469-478 ◽  
Author(s):  
Amy E. Kerdok ◽  
Andrew A. Biewener ◽  
Thomas A. McMahon ◽  
Peter G. Weyand ◽  
Hugh M. Herr
Keyword(s):  
Reaction Force ◽  
Force Plate ◽  
Metabolic Cost ◽  
Running Economy ◽  
Leg Length ◽  
Kinematic Data ◽  
Surface Stiffness ◽  
Leg Stiffness ◽  
Compliant Surfaces ◽  
Male Subjects

Mammals use the elastic components in their legs (principally tendons, ligaments, and muscles) to run economically, while maintaining consistent support mechanics across various surfaces. To examine how leg stiffness and metabolic cost are affected by changes in substrate stiffness, we built experimental platforms with adjustable stiffness to fit on a force-plate-fitted treadmill. Eight male subjects [mean body mass: 74.4 ± 7.1 (SD) kg; leg length: 0.96 ± 0.05 m] ran at 3.7 m/s over five different surface stiffnesses (75.4, 97.5, 216.8, 454.2, and 945.7 kN/m). Metabolic, ground-reaction force, and kinematic data were collected. The 12.5-fold decrease in surface stiffness resulted in a 12% decrease in the runner's metabolic rate and a 29% increase in their leg stiffness. The runner's support mechanics remained essentially unchanged. These results indicate that surface stiffness affects running economy without affecting running support mechanics. We postulate that an increased energy rebound from the compliant surfaces studied contributes to the enhanced running economy.

Transparency enhancement for an active knee orthosis by a constraint-free mechanical design and a gait phase detection based predictive control

Meccanica ◽  
2016 ◽  
Vol 52 (3) ◽  
pp. 729-748 ◽  
Author(s):  
Viet Anh Dung Cai ◽  
Aurelien Ibanez ◽  
Consuelo Granata ◽  
Viet Thang Nguyen ◽  
Minh Tam Nguyen
Keyword(s):  
Predictive Control ◽  
Mechanical Design ◽  
Phase Detection ◽  
Gait Phase ◽  
Knee Orthosis

scholarly journals Experimental Demonstration of the Lower Leg Trajectory Error Framework Using Physiological Data as Inputs

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Kathryn M. Olesnavage ◽  
Victor Prost ◽  
William Brett Johnson ◽  
Matthew J. Major ◽  
Amos G. Winter
Keyword(s):  
Mechanical Design ◽  
Lower Leg ◽  
Physiological Data ◽  
Vertical Position ◽  
Trajectory Error ◽  
Ankle Stiffness ◽  
Rms Error ◽  
Prosthetic Feet ◽  
The Relationship ◽  
Error Testing

Abstract While many studies have attempted to characterize the mechanical behavior of passive prosthetic feet to understand their influence on amputee gait, the relationship between mechanical design and biomechanical performance has not yet been fully articulated from a fundamental physics perspective. A novel framework, called lower leg trajectory error (LLTE) framework, presents a means of quantitatively optimizing the constitutive model of prosthetic feet to match a reference kinematic and kinetic dataset. This framework can be used to predict the required stiffness and geometry of a prosthesis to yield a desired biomechanical response. A passive prototype foot with adjustable ankle stiffness was tested by a unilateral transtibial amputee to evaluate this framework. The foot condition with LLTE-optimal ankle stiffness enabled the user to replicate the physiological target dataset within 16% root-mean-square (RMS) error. Specifically, the measured kinematic variables matched the target kinematics within 4% RMS error. Testing a range of ankle stiffness conditions from 1.5 to 24.4 N·m/deg with the same user indicated that conditions with lower LLTE values deviated the least from the target kinematic data. Across all conditions, the framework predicted the horizontal/vertical position, and angular orientation of the lower leg during midstance within 1.0 cm, 0.3 cm, and 1.5 deg, respectively. This initial testing suggests that prosthetic feet designed with low LLTE values could offer benefits to users. The LLTE framework is agnostic to specific foot designs and kinematic/kinetic user targets, and could be used to design and customize prosthetic feet.

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