Article
Refine
Year of publication
Institute
- Fachbereich Medizintechnik und Technomathematik (1546) (remove)
Has Fulltext
- no (1546) (remove)
Document Type
- Article (1546) (remove)
Keywords
- LAPS (4)
- CellDrum (3)
- hydrogen peroxide (3)
- impedance spectroscopy (3)
- Bacillus atrophaeus (2)
- Boundary integral equations (2)
- Conductive boundary condition (2)
- Empirical process (2)
- Field-effect sensor (2)
- Goodness-of-fit test (2)
- Independence test (2)
- Light-addressable potentiometric sensor (2)
- Paired sample (2)
- Parametric bootstrap (2)
- Raman spectroscopy (2)
- Stiffness (2)
- Transmission eigenvalues (2)
- constructive alignment (2)
- damage (2)
- examination (2)
- field-effect sensor (2)
- frequency mixing magnetic detection (2)
- likelihood ratio test (2)
- locomotion (2)
- long-term retention (2)
- multimodal (2)
- muscle fascicle behavior (2)
- not identically distributed (2)
- practical learning (2)
- tobacco mosaic virus (TMV) (2)
- ultrasound (2)
- ultrasound imaging (2)
- (Bio)degradation (1)
- Acceleration (1)
- Achilles tendon (1)
- Adaptive control (1)
- Afterload (1)
- Ageing (1)
- AlterG (1)
- Alzheimer's disease (1)
- Anastomotic leakage (1)
- Anatomy (1)
- Annulus Fibrosus (1)
- Architectural gear ratio (1)
- Assistive technology (1)
- Asymptotic efficiency (1)
- Autolysis (1)
- Automatic control (1)
- Bacillus atrophaeus spores (1)
- Bacillus sp (1)
- Balance (1)
- Biocomposites (1)
- Biomechanical simulation (1)
- Biosolubilization (1)
- Booster Station (1)
- Bootstrap (1)
- Bootstrapping (1)
- Boundary integral equations, (1)
- Brownian Pillow (1)
- CNOT (1)
- Calorimetric gas sensor (1)
- Capacitive field-effect (1)
- Capacitive model (1)
- Cardiac myocytes (1)
- Cardiac tissue (1)
- Categorial variable (1)
- Cell permeability (1)
- Cellular force (1)
- Cementoblast (1)
- Censored data (1)
- Chemical images (1)
- Chemical imaging sensor (1)
- Chemical sensor (1)
- Circular Dichroism (1)
- Co-managed care (1)
- Coal (1)
- Collective risk model (1)
- Competitiveness (1)
- Complex System (1)
- Complex-valued eigenvalues (1)
- Compliance (1)
- Compression (1)
- Computational biomechanics (1)
- Concomitant (1)
- Conductive Boundary Condition (1)
- Conservation laws (1)
- Constitutive model (1)
- Contractile tension (1)
- Contractility (1)
- Coverage probability (1)
- Cramér-von-Mises statistic (1)
- Cramér-von-Mises test (1)
- Cross border adjustment mechanism (1)
- Crámer–von-Mises distance (1)
- C–V method (1)
- DNA biosensor (1)
- DNA hybridization (1)
- DPA (dipicolinic acid) (1)
- Damage mechanics theory (1)
- Decomposition (1)
- Deep Learning (1)
- Dehydrogenase (1)
- Diaphorase (1)
- Dimensional splitting (1)
- Disc Degeneration (1)
- Discontinuous fractures (1)
- Discrete Optimization (1)
- Distorsion des oberen Sprunggelenks (1)
- Drug simulation (1)
- E-Mobility (1)
- EIS capacitive sensor (1)
- ES-FEM (1)
- Eigenvalue trajectories (1)
- Elderly (1)
- Electrolyte–insulator–semiconductor (1)
- Electromagnetism (1)
- Electromechanical modeling (1)
- Elektroenzephalographie (1)
- Elemental (1)
- End-to-end colorectal anastomosis (1)
- Endothelial cells (1)
- Endothelial dysfunction (1)
- Energy-intensive industry (1)
- Entropy solution (1)
- Enzymatic biosensor (1)
- Enzyme coverage (1)
- Enzyme logic gate (1)
- Equivalence test (1)
- Esophageal Doppler monitor (1)
- Exponential Euler scheme, (1)
- Exponential time differencing (1)
- External knee adduction moments (1)
- FS-FEM (1)
- Fall prevention (1)
- Field effect (1)
- Field-effect biosensor (1)
- Finite difference methods (1)
- Finite element analysis (1)
- Finite element modelling (1)
- Floor prices (1)
- Force (1)
- Forces (1)
- Fracture configuration (1)
- Fracture simulation (1)
- Freeze–thaw process (1)
- Frequency adaption (1)
- Frequency mixing magnetic detection (1)
- Functional Delta Method (1)
- Gamma distribution (1)
- Glaucoma (1)
- Goodness-of-fit tests for uniformity (1)
- Ground-level falls (1)
- H2 (1)
- Hadamard differentiability (1)
- Haemodialysis (1)
- Handbike (1)
- Heart tissue culture (1)
- Helmholtz equation (1)
- Heterostructure (1)
- Higher-order codes (1)
- Hodgkin–Huxley models (1)
- Hoeffding-Blum-Kiefer-Rosenblatt independence test (1)
- Homogenization (1)
- Hotelling’s T² test (1)
- Human-Computer interaction (1)
- Hydrogen peroxide (1)
- Hydrogenotrophic methanogens (1)
- Image Reconstruction (1)
- Impedance spectroscopy (1)
- Implicit methods (1)
- Incomplete data (1)
- Induced pluripotent stem cells (1)
- Inotropic compounds (1)
- Integrated empirical distribution (survival) function (1)
- Interior Neumann eigenvalues (1)
- Interior transmission eigenvalues (1)
- Interior transmission problem (1)
- Intervertebral Disc (1)
- Intradiscal Pressure (1)
- Inverse Scattering (1)
- Inverse dynamic problem (1)
- Inverse kinematic problem (1)
- Inverse scattering (1)
- Inverse spectral problem (1)
- Ion channels (1)
- Iterative learning control (1)
- Kinetic energy (1)
- LPS (1)
- Lab-on-Chip (1)
- Label-free detection (1)
- Langevin theory (1)
- Layer-by-layer adsorption (1)
- LbL films (1)
- Light-addressable Potentiometric Sensor (1)
- Lipopolysaccharide (1)
- Liver (1)
- Long COVID (1)
- MOS (1)
- Machine learning (1)
- Magnetic nanoparticles (1)
- Manipulated variables (1)
- Marginal homogeneity test (1)
- Matrix exponential (1)
- Mechanotransduction (1)
- Metascintillator (1)
- Methane (1)
- Methanogenesis (1)
- Microcirculation (1)
- Micromagnetic simulation (1)
- Mild cognitive impairment (1)
- Mobility (1)
- Mobility tests (1)
- Mobility transition (1)
- Monotone methods (1)
- Multi-criteria decision analysis (1)
- Multi-dimensional partial differential equations (1)
- Multi-sample problem (1)
- Multianalyte detection (1)
- Multiple TOF kernels (1)
- Muscle (1)
- Muscle Fascicle (1)
- Muscle Force (1)
- Musculoskeletal model (1)
- Musculoskeletal system (1)
- Myocardial infarction and cardiac death (1)
- NONOate (1)
- Natural fibres (1)
- Negative impedance convertor (1)
- Neural Network (1)
- Nitric Oxide (1)
- Nitric Oxide Donor (1)
- Non-parallel fissures (1)
- Nonequilibrium dynamics (1)
- Nonlinear Dynamics (1)
- Nonlinear PDEs (1)
- Nonlinear eigenvalue problems (1)
- Nucleus Pulposus (1)
- Numerical inversion of Laplace transforms (1)
- Numerical linear algebra (1)
- Numerics (1)
- O2 plasma (1)
- Ocular blood flow (1)
- Organic light-emitting diode display (1)
- Parabolic SPDEs (1)
- Paralympic sport (1)
- Penicillin (1)
- Pharmacology (1)
- Physiology (1)
- Poly(allylamine hydrochloride) (1)
- Poly(d,l-lacticacid) (1)
- Polyimide (1)
- Polymer-matrix composites (1)
- Post-COVID-19 syndrome (1)
- Potential theory (1)
- Preference assessment (1)
- Product-integration (1)
- Proximal humerus fracture (1)
- Psychiatrische Biomarker (1)
- Pulsations (1)
- Pump System (1)
- RVA (1)
- Reaction-diffusion systems (1)
- Real distinct pole (1)
- Real-time monitoring (1)
- Recombinant activated protein C (1)
- Regionalization (1)
- Rehabilitation Technology and Prosthetics (1)
- Rehabilitation engineering (1)
- Resampling test (1)
- Resolvent Operator (1)
- Resonance-mode measurement (1)
- Retinal vessel analysis (1)
- Retinal vessels (1)
- Robotic rehabilitation (1)
- Rotator cuff (1)
- Running (1)
- S-FEM (1)
- ScaLAPACK (1)
- Schlafspindeldetektion (1)
- Semi-parametric random censorship model (1)
- Septic cardiomyopathy (1)
- Simulation (1)
- Simultaneous determination (1)
- Sn₃O₄ (1)
- Source term (1)
- Spleen (1)
- Sprunggelenkorthesen (1)
- Steel industry (1)
- Sterilisation process (1)
- Stress concentrations (1)
- SunRav BookEditor (1)
- Surgical Navigation and Robotics (1)
- Surgical staplers (1)
- Survival analysis (1)
- TMV adsorption (1)
- TOF PET (1)
- Ta₂O₅ gate (1)
- Technical Operations Research (TOR) (1)
- Tendon Rupture (1)
- Tendon properties (1)
- Tension (1)
- Tinetti test (1)
- Transmission Eigenvalues (1)
- Uniaxial compression test (1)
- Vapnik–Čhervonenkis class (1)
- Variable height stapler design (1)
- Vascular response (1)
- Vasomotions (1)
- Velocity (1)
- Visual field asymmetry (1)
- Volterra integral equation (1)
- Volume of confidence regions (1)
- Volume status (1)
- XOR (1)
- achilles tendon (1)
- actin cytoskeleton (1)
- adipose-derived stromal cells (ASCs) (1)
- adsorption (1)
- agility (1)
- allocation (1)
- anaesthetic complications (1)
- anisotropy (1)
- ankle braces (1)
- ankle sprain (1)
- annealing (1)
- aortic perfusion (1)
- aquaculture (1)
- artificial olfactory image (1)
- asymptotic relative efficiency (1)
- barium strontium titanate (1)
- biaxial tensile experiment (1)
- biomechanics (1)
- biopotential electrodes (1)
- biosensor (1)
- biosensors (1)
- bootstrap (1)
- calorimetric gas sensor (1)
- calorimetric gas sensor;hydrogen peroxide;wireless sensor system (1)
- capacitive field-effect sensor (1)
- carbonized rice husk (1)
- cardiomyocyte biomechanics (1)
- catalytic metal (1)
- cell aerosolization (1)
- cell atomization (1)
- central symmetry test (1)
- cerebral small vessel disease (1)
- chance constrained programming (1)
- chemical sensor (1)
- chip-based sensor setup (1)
- cognitive impairment (1)
- community dwelling (1)
- complete block symmetry (1)
- computational fluid dynamics analysis (1)
- conditional excess distribution (1)
- conditional expectation principle (1)
- confidence interval (1)
- connective tissue (1)
- constitutive modeling (1)
- contactless conductivity sensor (1)
- correlation (1)
- coupled Néel–Brownian relaxation dynamics (1)
- covariance principle (1)
- dental trauma (1)
- dialysis (1)
- difficult airway (1)
- distance learning (1)
- distorted element (1)
- double-lumen tube intubation (1)
- drop jump (1)
- e-books (1)
- e-issues (1)
- eigensolvers (1)
- elastic scattering (1)
- electrical conductivity of liquids (1)
- electrolyte-insulator semiconductor sensor (EIS) (1)
- electromyography (1)
- electronic nose (1)
- endoluminal (1)
- endospores (1)
- energy absorption (1)
- energy dissipation (1)
- enzymatic (bio)degradation (1)
- enzyme cascade (1)
- exchangeability test (1)
- extracorporeal membrane oxygenation (1)
- fibulare Bandruptur (1)
- field-effect structure (1)
- force generation (1)
- forecast (1)
- forehead EEG (1)
- frequency mixing (1)
- functional data (1)
- gait (1)
- gas sensor (1)
- glucose oxidase (GOx) (1)
- goodness-of-fit test (1)
- healthy aging (1)
- heavy metals (1)
- hiPS cardiomyocytes (1)
- high-intensity exercise (1)
- high-k material (1)
- horseradish peroxidase (HRP) (1)
- huge dimensional data (1)
- humic acid (1)
- hydroxylation (1)
- hyper-gravity (1)
- hyperelastic (1)
- hypo-gravity (1)
- immobilization (1)
- in-ear EEG (1)
- in-situ monitoring (1)
- independence test (1)
- intraclass correlation coefficient (1)
- key performance indicators (1)
- lable-free detection (1)
- light-addressable potentiometric sensor (1)
- light-addressing technologies (1)
- lignite (1)
- limit analysis (1)
- lipopolysaccharide (1)
- magnetic actuation (1)
- magnetic beads (1)
- magnetic biosensing (1)
- magnetic nanoparticles (1)
- magnetic relaxation (1)
- magnetic sandwich immunoassay (1)
- magnetic sensing (1)
- magnetic separation (1)
- magnetic tweezers (1)
- magnetophoretic velocity (1)
- mechanical buffer (1)
- metal-oxide-semiconductor structure (1)
- method of fundamental solutions (1)
- microfluidics (1)
- micromagnetic simulation (1)
- multi-functional material (1)
- multinomial distribution (1)
- multiparametric immunoassays (1)
- multivariate normal distribution (1)
- muscle mechanics (1)
- nanobelts (1)
- non-simplex S-FEM elements (1)
- novel photoexcitation method (1)
- optical sensor setup (1)
- optical spore trapping (1)
- optical trapping (1)
- organosilanes (1)
- overload (1)
- parabolic flight (1)
- performance analysis (1)
- performance testing (1)
- physiology (1)
- plant virus detection (1)
- plug-based microfluidic device (1)
- poly(d, l-lactic acid) (1)
- portfolio risk (1)
- prevention (1)
- psychosocial (1)
- random effects (1)
- random effects meta-regression model (1)
- rehabilitation (1)
- reliability of structures (1)
- retinal microvasculature (1)
- retinal vessels (1)
- running (1)
- rupture of the fibular ligament (1)
- sEMG (1)
- sarcomere operating length (1)
- scanned light pulse technique (1)
- separable Hilbert space (1)
- series elastic element behavior (1)
- shakedown analysis (1)
- shoulder (1)
- silanization (1)
- simulation (1)
- smooth muscle contraction (1)
- softs (1)
- spatial resolution (1)
- sprint start (1)
- standard error of measurement (1)
- sterilisation (1)
- sterilization (1)
- sterilization conditions (1)
- stiffness (1)
- stochastic programming (1)
- strain energy function (1)
- stretch reflex (1)
- stretch-shortening cycle (1)
- superparamagnetic bead (1)
- superparamagnetic nanoparticles (1)
- surface functionalization (1)
- surface modification (1)
- survival (1)
- temperature (1)
- tendon rupture (1)
- test-retest reliability (1)
- thermometry (1)
- tilted constant illumination (1)
- tri-lineage differentiation (1)
- turnip vein clearing virus (TVCV) (1)
- twin-fluid atomizer (1)
- ultrasonography (1)
- uniformly most powerful invariant test (1)
- unloading (1)
- videolaryngoscopy (1)
- virgin passive (1)
- viscoelasticity (1)
- visualization (1)
- walking (1)
- walking gait (1)
- · Psychiatrische Erkrankungen/Diagnostik (1)
The deformation and damage laws of non-homogeneous irregular structural planes in rocks are the basis for studying the stability of rock engineering. To investigate the damage characteristics of rock containing non-parallel fissures, uniaxial compression tests and numerical simulations were conducted on sandstone specimens containing three non-parallel fissures inclined at 0°, 45° and 90° in this study. The characteristics of crack initiation and crack evolution of fissures with different inclinations were analyzed. A constitutive model for the discontinuous fractures of fissured sandstone was proposed. The results show that the fracture behaviors of fissured sandstone specimens are discontinuous. The stress–strain curves are non-smooth and can be divided into nonlinear crack closure stage, linear elastic stage, plastic stage and brittle failure stage, of which the plastic stage contains discontinuous stress drops. During the uniaxial compression test, the middle or ends of 0° fissures were the first to crack compared to 45° and 90° fissures. The end with small distance between 0° and 45° fissures cracked first, and the end with large distance cracked later. After the final failure, 0° fissures in all specimens were fractured, while 45° and 90° fissures were not necessarily fractured. Numerical simulation results show that the concentration of compressive stress at the tips of 0°, 45° and 90° fissures, as well as the concentration of tensile stress on both sides, decreased with the increase of the inclination angle. A constitutive model for the discontinuous fractures of fissured sandstone specimens was derived by combining the logistic model and damage mechanic theory. This model can well describe the discontinuous drops of stress and agrees well with the whole processes of the stress–strain curves of the fissured sandstone specimens.
Frequency mixing magnetic detection (FMMD) is a sensitive and selective technique to detect magnetic nanoparticles (MNPs) serving as probes for binding biological targets. Its principle relies on the nonlinear magnetic relaxation dynamics of a particle ensemble interacting with a dual frequency external magnetic field. In order to increase its sensitivity, lower its limit of detection and overall improve its applicability in biosensing, matching combinations of external field parameters and internal particle properties are being sought to advance FMMD. In this study, we systematically probe the aforementioned interaction with coupled Néel–Brownian dynamic relaxation simulations to examine how key MNP properties as well as applied field parameters affect the frequency mixing signal generation. It is found that the core size of MNPs dominates their nonlinear magnetic response, with the strongest contributions from the largest particles. The drive field amplitude dominates the shape of the field-dependent response, whereas effective anisotropy and hydrodynamic size of the particles only weakly influence the signal generation in FMMD. For tailoring the MNP properties and parameters of the setup towards optimal FMMD signal generation, our findings suggest choosing large particles of core sizes dc > 25 nm nm with narrow size distributions (σ < 0.1) to minimize the required drive field amplitude. This allows potential improvements of FMMD as a stand-alone application, as well as advances in magnetic particle imaging, hyperthermia and magnetic immunoassays.
Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes.
Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here.
During rapid deceleration of the body, tendons buffer part of the elongation of the muscle-tendon unit (MTU), enabling safe energy dissipation via eccentric muscle contraction. Yet, the influence of changes in tendon stiffness within the physiological range upon these lengthening contractions is unknown. This study aimed to examine the effect of training-induced stiffening of the Achilles tendon on triceps surae muscle-tendon behavior during a landing task. Twenty-one male subjects were assigned to either a 10-week resistance-training program consisting of single-leg isometric plantarflexion (n = 11) or to a non-training control group (n = 10). Before and after the training period, plantarflexion force, peak Achilles tendon strain and stiffness were measured during isometric contractions, using a combination of dynamometry, ultrasound and kinematics data. Additionally, testing included a step-landing task, during which joint mechanics and lengths of gastrocnemius and soleus fascicles, Achilles tendon, and MTU were determined using synchronized ultrasound, kinematics and kinetics data collection. After training, plantarflexion strength and Achilles tendon stiffness increased (15 and 18%, respectively), and tendon strain during landing remained similar. Likewise, lengthening and negative work produced by the gastrocnemius MTU did not change detectably. However, in the training group, gastrocnemius fascicle length was offset (8%) to a longer length at touch down and, surprisingly, fascicle lengthening and velocity were reduced by 27 and 21%, respectively. These changes were not observed for soleus fascicles when accounting for variation in task execution between tests. These results indicate that a training-induced increase in tendon stiffness does not noticeably affect the buffering action of the tendon when the MTU is rapidly stretched. Reductions in gastrocnemius fascicle lengthening and lengthening velocity during landing occurred independently from tendon strain. Future studies are required to provide insight into the mechanisms underpinning these observations and their influence on energy dissipation.
Comparison of different training algorithms for the leg extension training with an industrial robot
(2018)
In the past, different training scenarios have been developed and implemented on robotic research platforms, but no systematic analysis and comparison have been done so far. This paper deals with the comparison of an isokinematic (motion with constant velocity) and an isotonic (motion against constant weight) training algorithm. Both algorithms are designed for a robotic research platform consisting of a 3D force plate and a high payload industrial robot, which allows leg extension training with arbitrary six-dimensional motion trajectories. In the isokinematic as well as the isotonic training algorithm, individual paths are defined i n C artesian s pace by sufficient s upport p oses. I n t he i sotonic t raining s cenario, the trajectory is adapted to the measured force as the robot should only move along the trajectory as long as the force applied by the user exceeds a minimum threshold. In the isotonic training scenario however, the robot’s acceleration is a function of the force applied by the user. To validate these findings, a simulative experiment with a simple linear trajectory is performed. For this purpose, the same force path is applied in both training scenarios. The results illustrate that the algorithms differ in the force dependent trajectory adaption.
Training-induced increase in Achilles tendon stiffness affects tendon strain pattern during running
(2019)
Background
During the stance phase of running, the elasticity of the Achilles tendon enables the utilisation of elastic energy and allows beneficial contractile conditions for the triceps surae muscles. However, the effect of changes in tendon mechanical properties induced by chronic loading is still poorly understood. We tested the hypothesis that a training-induced increase in Achilles tendon stiffness would result in reduced tendon strain during the stance phase of running, which would reduce fascicle strains in the triceps surae muscles, particularly in the mono-articular soleus.
Methods
Eleven subjects were assigned to a training group performing isometric singleleg plantarflexion contractions three times per week for ten weeks, and another ten subjects formed a control group. Before and after the training period, Achilles tendon stiffness was estimated, and muscle-tendon mechanics were assessed during running at preferred speed using ultrasonography, kinematics and kinetics.
Results
Achilles tendon stiffness increased by 18% (P <0:01) in the training group, but the associated reduction in strain seen during isometric contractions was not statistically significant. Tendon elongation during the stance phase of running was similar after training, but tendon recoil was reduced by 30% (P <0:01), while estimated tendon force remained unchanged. Neither gastrocnemius medialis nor soleus fascicle shortening during stance was affected by training.
Discussion
These results show that a training-induced increase in Achilles tendon
stiffness altered tendon behaviour during running. Despite training-induced changes in tendon mechanical properties and recoil behaviour, the data suggest that fascicle shortening patterns were preserved for the running speed that we examined. The asymmetrical changes in tendon strain patterns supports the notion that simple inseries models do not fully explain the mechanical output of the muscle-tendon unit during a complex task like running.
Neuromuscular strength training of the leg extensor muscles plays an important role in the rehabilitation and prevention of age and wealth related diseases. In this paper, we focus on the design and implementation of a Cartesian admittance control scheme for isotonic training, i.e. leg extension and flexion against a predefined weight. For preliminary testing and validation of the designed algorithm an experimental research and development platform consisting of an
industrial robot and a force plate mounted at its end-effector has been used. Linear, diagonal and arbitrary two-dimensional motion trajectories with different weights for the leg extension and flexion part are applied. The proposed algorithm is easily adaptable to trajectories consisting of arbitrary six-dimensional poses and allows the implementation of individualized trajectories.
To prevent the reduction of muscle mass and loss of strength coming along with the human aging process, regular training with e.g. a leg press is suitable. However, the risk of training-induced injuries requires the continuous monitoring and controlling of the forces applied to the musculoskeletal system as well as the velocity along the motion trajectory and the range of motion. In this paper, an adaptive norm-optimal iterative learning control algorithm to minimize the knee joint loadings during the leg extension training with an industrial robot is proposed. The response of the algorithm is tested in simulation for patients with varus, normal and valgus alignment of the knee and compared to the results of a higher-order iterative learning control algorithm, a robust iterative learning control and a recently proposed conventional norm-optimal iterative learning control algorithm. Although significant improvements in performance are made compared to the conventional norm-optimal iterative learning control algorithm with a small learning factor, for the developed approach as well as the robust iterative learning control algorithm small steady state errors occur.