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Moving from antagonistic pneumatic Air Muscle actuation to motor-based actuation requires a distinctly different design of motor component. This design is presented in the context of recent developments on the Shadow Dextrous Hand. Antagonistic systems provide certain advantages, but the constant load on the system produces wear and as it is well known, pneumatics offers its own control and mobility...
INTRODUCTION: Many disorders in clinical orthopedics present tissue degeneration and lack of repair due to lack of a scaffold., Chitosan is a sugar polymer that is produced from chitin., The current abstract describes our experience with chitosan as a tissue regeneration supporting scaffold. MATERIALS AND METHODS:, Several models were evaluated including the rat acute rotator cuff model, the lapine...
The Achilles tendon plays an important role in our daily activities and studies have shown that tendon properties, such as morphology and stiffness, are related to aging, activity levels and genders. A better understanding of its morphology and mechanical properties will provide guidance to health professionals on intervention recommendation. However, the majority of the existing studies investigated...
In this study, it is aimed at measuring for the first time the isometric force of human gracilis (G) muscle as a function of joint angle, intraoperatively. Experiments were conducted during anterior cruciate ligament reconstruction surgery. The knee angle was fixed at 120°, 90°, 60°, 30° and 0° respectively and active isometric forces of this muscle were measured using a buckle force transducer. Limited...
It has been shown that non-tendinous structures play a major role in force transmission: epimuscular myofascial force transmission. Such force transmission was shown to cause substantial strain distributions along muscle fibers indicating serial heterogeneity of sarcomere lengths. Recent studies showed evidence on sizable inter-antagonistic epimuscular myofascial force transmission. It is hypothesized...
In this study, the adequency of the current amplitudes during intraoperative force measurement of human gracilis muscle is investigated. During anterior cruciate ligament (ACL) reconstruction, gracilis muscle isometric force is measured after stimulating the muscle by different current amplitudes (130, 140, 150 and 160 mA) at fixed knee angles 90°, 60° and 30°. When the knee angle is fixed at 60°...
This paper introduces a model to estimate knee joint extension moment during isokinetic contraction exercise. It is possible to estimate knee joint extension moment combining Hill-type muscle model, analytic results on moment arm, musculotendon length and muscle activation if muscle parameters are exactly known. However, the muscle parameters are all different to each person. And it is almost impossible...
We have reported earlier a new method for estimating reflex threshold in spastic muscles of stroke survivors, using controlled amplitude taps superimposed on progressive and controlled muscle indentation of the bicipital tendon in the bicipital fossa. This muscle indentation is done with a linear actuator positioned over the biceps muscle tendon at the elbow. In the course of testing for increased...
A typical prosthetic limb has sensory shortcomings, one of which is lack of kinesthesia. Conventional methods to evoke kinesthesia, which would be required for a precise control of prosthetic limbs, include tendon vibration and skin stretch, but these produce only the sensation of small movements. In this study, tendon vibration is extended to evoke sensations of a more rapid movement. A stimulation...
Now more than ever, progresses in information technology applied to rehabilitation robotics give new hopes to people recovering from different kinds of diseases and injuries. Beside the standard application of EMG signals to analyze disabilities or to track progress in rehabilitation, more focus has been put on controlling robot arms and exoskeletons. In recent years, biomechanists have developed...
We have developed a vector tissue Doppler imaging (TDI) system based on a clinical scanner that can be used to measure muscle velocities independent of the direction of motion. This method overcomes the limitations of conventional Doppler ultrasound, which can only measure velocity components along the ultrasound beam. In this study, we utilized this method to investigate the rectus femoris muscle...
Prosthetic hip joint dislocation phenomenon is generated by the hip joint simulator and the effect of the femoral head diameter is studied under the same condition which is similar to the condition in daily activities. Impedance control is applied to control the hip joint motion and the joint contact force simultaneously in order to take into account the constraint caused by surrounding tendons, muscles,...
A portable ankle rehabilitation robot with intelligent stretching and game-based active movement training was used to treat the spastic impaired ankle of children with cerebral palsy over six weeks. The subject's calf muscles and Achilles tendon properties were evaluated before and after treatment using ultrasonography and biomechanical measures. It was found that there were decreased Achilles tendon...
Many clinical measures of spasticity, such as Ashworth tests and tendon tap responses, are linked to stretch reflex thresholds but these methods are relatively imprecise and unreliable. To address this deficit, we examined the utility of a system that relies on a small position controlled actuator to better estimate this threshold. We compared the reflex threshold estimates in the passive spastic...
In this paper, we present a simple approach for estimating the average longitudinal strains from models reconstructed from medical images. It can be used for many incompressible generalized cylindrical tissues, such as tendons, ligaments, and fusiform muscles; the major deformation directions of these soft tissues are along the longitudinal axes. The method is especially useful when pre- and post-deformation...
Postural control strategies applied by a subject in two different physical environments (phy env) were explored by using tendon vibration technique. EMG data from left and right Tibialis Anterior and Gastrocnemius muscles have been received from a subject while standing still on a force platform in two different conditions (eyes open and closed) during 180 sec long trials at the phy env's created...
Tendon repair after injury poses a significant problem due to variable success rates. Consequently, tissue engineering with stem cells has been explored to enable replacement of damaged tendon with regenerated, living tissue. Interestingly, there are no known growth factors available to induce and guide stem cell differentiation toward the tendon lineage in a tissue engineering system. This is due...
Recent literature suggests that inducing proprioceptive movement illusions with predefined movement trajectories via tendon vibration requires use of multiple vibrators and precisely controlled frequency profiles. In this study, we report the design, modeling and control of a compact, low-cost tendon vibrator and illustrate its capability of accurately following time-varying frequency profiles. During...
This paper presents a model to estimate hamstring tendon slack length for knee flexor moment approximations. The muscle force is very sensitive to the tendon slack length. To predict a tendon slack length, exact muscle parameters are needed. But it is difficult to measure all of the muscle parameters from human body. So we propose the algorithm which finds the tendon slack length of hamstring for...
A 2-D strain estimation algorithm was used to estimate tendon strain from ultrasound data collected during muscle twitch contractions. We first used speckle tracking techniques to estimate frame-to-frame displacements of all pixels within a rectangular region of interest (ROI) positioned over a tendon. A weighted, least-squares approach was then solved for the displacements of the ROI endpoints that...
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