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1.
Gene ; 766: 145157, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32949697

RESUMEN

Glycolytic potential (GP) calculated based on glucose, glycogen, glucose-6-phosphate, and lactate contents is a critical factor for multiple meat quality characteristics. However, the genetic basis of glycolytic metabolism is still unclear. In this study, we constructed six RNA-Seq libraries using longissimus dorsi (LD) muscles from pigs divergent for GP phenotypic values and generated the whole genome-wide gene expression profiles. Furthermore, we identified 25,880 known and 220 novel genes from these skeletal muscle libraries, and 222 differentially expressed genes (DEGs) between the higher and lower GP groups. Notably, we found that the Lactate dehydrogenase B (LDHB) and Fructose-2, 6-biphosphatase 3 (PFKFB3) expression levels were higher in the higher GP group than the lower GP group, and positively correlated with GP and lactic acid (LA), and reversely correlated with pH value at 45 min postmortem (pH45min). Besides, LDHB and PFKFB3 expression were positively correlated with drip loss measured at 48 h postmortem (DL48h) and drip loss measured at 24 h postmortem (DL24h). Collectively, we identified a serial of DEGs as the potential key candidate genes affecting GP and found that LDHB and PFKFB3 are closely related to GP and GP-related traits. Our results lay a solid basis for in-depth studies of the regulatory mechanisms on GP and GP-related traits in pigs.


Asunto(s)
Glucólisis/genética , Músculo Esquelético/metabolismo , Porcinos/genética , Transcriptoma/genética , Animales , Perfilación de la Expresión Génica/métodos , Glucosa/genética , Glucógeno/genética , Isoenzimas/genética , L-Lactato Deshidrogenasa/genética , Ácido Láctico/metabolismo , Carne , Fenotipo , Fosfofructoquinasa-2/genética , Porcinos/metabolismo
2.
Georgian Med News ; (306): 10-18, 2020 Sep.
Artículo en Ruso | MEDLINE | ID: mdl-33130638

RESUMEN

Objective - to study the effect of hip contractures on the strength of the thigh muscles. Gait analysis was performed in the OpenSim 4.0 program, gait2394 was taken as the basis. Created 4 models with contractures of varying severity. We analyzed the change in the work of the thigh muscles in normal conditions, with adduction, flexion-adduction and flexion-adduction contractures with shortening. According to the data obtained in modeling the adductive and flexor-adducing contractures of the hip joint, it can be noted that contracture changes the work of the muscles around the hip joint. It was noted that modeling only adduction contracture causes noticeable changes in the medial group of femoral muscles and muscle stabilizers. Of the muscles of the posterior thigh group, m.semimembranosus, m.semitendinosus and m.biceps femoris are most susceptible to changes. These muscles change the level of load, and most importantly, periods of excitation and muscle relaxation shift. Simulation of combined flexion-adduction contracture showed that muscle dysfunctions increase, and m.sartorius, an anterior thigh muscle, was added to the muscles in which noticeable changes additionally occurred. With simulated adduction and flexion adduction contractures, changes occur in all the muscles of the thigh, periods of their excitement and relaxation shift, but the level of muscle tension is close to normal values - not exceeding them by 20-30%. Flexion-leading contracture with shortening of the limb leads to a distortion of muscle parameters in the form of excessive loads for the step (up to 100-300%). Based on the obtained simulation results, the inability of the muscles to develop the necessary efforts leads to a change in the parameters of the step in the form of a decrease in the length of the step and the duration of the periods of support on the foot, a change in the nature of the transfer of the foot. It is logical to assume that a long period of impaired muscle function will lead to the development of sustainable changes in the walking pattern.


Asunto(s)
Contractura , Articulación de la Cadera , Cadera , Humanos , Músculo Esquelético , Muslo
3.
Nat Commun ; 11(1): 5661, 2020 11 09.
Artículo en Inglés | MEDLINE | ID: mdl-33168829

RESUMEN

Sarcopenia is characterized by decreased skeletal muscle mass and function with age. Aged muscles have altered lipid compositions; however, the role and regulation of lipids are unknown. Here we report that FABP3 is upregulated in aged skeletal muscles, disrupting homeostasis via lipid remodeling. Lipidomic analyses reveal that FABP3 overexpression in young muscles alters the membrane lipid composition to that of aged muscle by decreasing polyunsaturated phospholipid acyl chains, while increasing sphingomyelin and lysophosphatidylcholine. FABP3-dependent membrane lipid remodeling causes ER stress via the PERK-eIF2α pathway and inhibits protein synthesis, limiting muscle recovery after immobilization. FABP3 knockdown induces a young-like lipid composition in aged muscles, reduces ER stress, and improves protein synthesis and muscle recovery. Further, FABP3 reduces membrane fluidity and knockdown increases fluidity in vitro, potentially causing ER stress. Therefore, FABP3 drives membrane lipid composition-mediated ER stress to regulate muscle homeostasis during aging and is a valuable target for sarcopenia.


Asunto(s)
Envejecimiento/fisiología , Estrés del Retículo Endoplásmico/fisiología , Proteína 3 de Unión a Ácidos Grasos/metabolismo , Lípidos de la Membrana/metabolismo , Músculo Esquelético/metabolismo , Animales , Línea Celular , Factor 2 Eucariótico de Iniciación/metabolismo , Proteína 3 de Unión a Ácidos Grasos/genética , Femenino , Técnicas de Silenciamiento del Gen , Lipidómica , Fluidez de la Membrana , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Esquelético/patología , Mioblastos/patología , Mioblastos/fisiología , Fosfolípidos/metabolismo , Proteínas Serina-Treonina Quinasas , Sarcopenia , Regulación hacia Arriba
4.
Nat Commun ; 11(1): 5166, 2020 10 14.
Artículo en Inglés | MEDLINE | ID: mdl-33056999

RESUMEN

Many creatures have the ability to traverse challenging environments by using their active muscles with anisotropic structures as the motors in a highly coordinated fashion. However, most artificial robots require multiple independently activated actuators to achieve similar purposes. Here we report a hydrogel-based, biomimetic soft robot capable of multimodal locomotion fueled and steered by light irradiation. A muscle-like poly(N-isopropylacrylamide) nanocomposite hydrogel is prepared by electrical orientation of nanosheets and subsequent gelation. Patterned anisotropic hydrogels are fabricated by multi-step electrical orientation and photolithographic polymerization, affording programmed deformations. Under light irradiation, the gold-nanoparticle-incorporated hydrogels undergo concurrent fast isochoric deformation and rapid increase in friction against a hydrophobic substrate. Versatile motion gaits including crawling, walking, and turning with controllable directions are realized in the soft robots by dynamic synergy of localized shape-changing and friction manipulation under spatiotemporal light stimuli. The principle and strategy should merit designing of continuum soft robots with biomimetic mechanisms.


Asunto(s)
Biomimética/métodos , Locomoción , Nanogeles/química , Robótica/métodos , Fricción , Músculo Esquelético/fisiología
5.
Artículo en Chino | MEDLINE | ID: mdl-33036526

RESUMEN

Objective: To study the differences of different signal processing method of surface electromyography (sEMG) in judging muscle fatigue. Methods: From July to October 2019, based on the model of simulated manual lifting operation, the original sEMG signals from 13 volunteers of brachial radial muscle, brachial two-headed muscle, triangle muscle, left vertical spine muscle, right vertical spine muscle and lateral femoral muscle were collected in the operation activities. Three different electromyography signal processing methods (all signal from motion beginning to the end, peak signal and ehe specified motion signal) were used to analyze the original data in time domain (RMS) and frequency domain (MDF) , the data difference between different electromyography signal processing methods was analyzed by using Wilcoxon rank and sum test and nonlinear curve fitting method. Results: The age of the subjects of the simulated lifting operation was (24.31±2.02) years old, height (173.78±4.84) cm, weight (66.28±5.58) kg, body mass index (BMI) 21.94±1.58. The thickness of triceps skinfold was (14.08±4.86) mm, and the thickness of the skin fold under the scapula was (15.54±3.59) mm. After processing the original signal data by using different sEMG signal interception methods, the normality test, Levene's test, and the Wilcoxon test showed that, except for the MDF index of the brachial two-headed muscle, the differences in the RMS and MDF signals of the other muscles were statistically significant (P<0.016) . The all signal processing method dealed with data distribution dispersion better than other methods, and the rate of change of RMS signal slope was higher than other methods. Non-linear regression results showed that all signal processing method had low volatility in processing data, and the regression equation had a high degree of fit. Conclusion: Different electromyography signal processing methods have differences. The all signal processing method which intercepts from starting point to the end point of action cycle has the least data volatility, and electromyography time domain and frequency domain index with the highest sensitivity of time, which is suitable for the application of surface electromyography to judge muscle fatigue in dynamic and complex operations.


Asunto(s)
Elevación , Fatiga Muscular , Adulto , Brazo , Electromiografía , Humanos , Músculo Esquelético , Adulto Joven
6.
Zhonghua Yi Xue Za Zhi ; 100(39): 3104-3108, 2020 Oct 27.
Artículo en Chino | MEDLINE | ID: mdl-33105963

RESUMEN

Objective: To explore the effect of a delayed pedicle gastrocnemius muscle flap transposition for the treatment of a knee joint deep infection secondary to wound necrosis after total knee arthroplasty (TKA). Methods: The clinical data of 7 patients treated in Shanxi Provincial People's Hospital with a delayed pedicle gastrocnemius muscle flap transposition from December 2015 to September 2019 for wound necrosis, exposed prosthesis and deep infection of knee joint after TKA were analyzed retrospectively. Before the muscle flap transplantation, 5 of the patients had received at least one debridement but failed for relapse, and resulted in an exposed prostheses and infected knee joint. Four patients were positive in their wounds or joint exudates bacterial culture, while the other 3 patients were negative but only with an obvious purulent secretion. The radiographs in all of the patients had no signs of lucent peripheral to or sink of the prosthesis. Results: The patients were followed-up for a mean time of 16.5 months (7-39 months). The flap and skin graft survived uneventfully with no pain, sinus, fistula, edema, and hematoma occurred. The appearances of the legs were normal. Only 1 patient had a mild limp, and the others gained almost a normal gait. One of the patients recurred 5 months after the gastrocnemius muscle flap transposition, and a two-stage revision procedure was applied, that involving a prosthesis remove and vancomycin impregnated cement (4 grams of vancomycin powder mixed with forty grams of polymethylmethacrylate) spacer implanted, and a new prosthesis was re-implanted 6 months later. The assessment of Knee Society Score (KSS) graded as: 4 patients classified as excellence, 2 as fine, 1 as general. Conclusions: Delayed pedicle gastrocnemius muscle flap transposition is an effective method for the complication of wound necrosis, deep infection, prosthesis exposure after TKA. This protocol was appropriate for those who have experienced a comparative long time of infection while had no signs of prosthesis loosening, and with which the implant may be salvaged, the defect be closed, and the infection be eradicated.


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Infecciones , Artroplastia de Reemplazo de Rodilla/efectos adversos , Humanos , Articulación de la Rodilla/cirugía , Músculo Esquelético , Estudios Retrospectivos
7.
Sheng Li Xue Bao ; 72(5): 667-676, 2020 Oct 25.
Artículo en Chino | MEDLINE | ID: mdl-33106837

RESUMEN

Sarcopenia is an age-related degenerative disease, in which skeletal muscle mass and function are reduced during aging process. Physical intervention is one of the most effective strategies available for the treatment of sarcopenia. Studies have shown that microRNAs (miRNAs), as important regulators of gene expression, play an important role in maintaining the homeostasis of senescent skeletal muscle cells by regulating skeletal muscle cell development (proliferation and differentiation), mitochondrial biogenesis, protein synthesis and degradation, inflammatory response and metabolic pathways. Furthermore, exercise can combat age-related changes in muscle mass, composition and function, which is associated with the changes in the expression and biological functions of miRNAs in skeletal muscle cells. In this article, we systematically review the regulatory mechanisms of miRNAs in skeletal muscle aging, and discuss the regulatory roles and molecular targets of exercise-mediated miRNAs in muscular atrophy during aging process, which may provide novel insights into the prevention and treatment of sarcopenia.


Asunto(s)
MicroARNs , Sarcopenia , Envejecimiento/genética , Terapia por Ejercicio , Humanos , MicroARNs/genética , Músculo Esquelético , Sarcopenia/genética , Sarcopenia/terapia
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 732-735, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018091

RESUMEN

In this study, an attempt has been made to distinguish between nonfatigue and fatigue conditions in surface Electromyography (sEMG) signal using the time frequency distribution obtained from analytic Bump Continuous Wavelet Transform. For the analysis, sEMG signals from biceps brachii muscle of 22 healthy subjects are acquired during isometric contraction protocol. The signals acquired is preprocessed and partitioned into ten equal segments followed by the decomposition of selected segments using analytic Bump wavelets. Further, Singular Value Decomposition is applied to the time frequency distribution matrix and the maximum singular value and entropy feature for each segment are obtained. The usefulness of both the features is estimated using the Wilcoxon sign rank test that gives higher significance with a p < .00001. It is observed that the proposed method is capable of analyzing the fatigue regions in sEMG signals.


Asunto(s)
Contracción Isométrica , Análisis de Ondículas , Electromiografía , Humanos , Fatiga Muscular , Músculo Esquelético
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2113-2116, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018423

RESUMEN

The purpose of this study was to develop an automatic method for the segmentation of muscle cross-sectional area on transverse B-mode ultrasound images of gastrocnemius medialis using a convolutional neural network(CNN). In the provided dataset images with both normal and increased echogenicity are present. The manually annotated dataset consisted of 591 images, from 200 subjects, 400 relative to subjects with normal echogenicity and 191 to subjects with augmented echogenicity. From the DICOM files, the image has been extracted and processed using the CNN, then the output has been post-processed to obtain a finer segmentation. Final results have been compared to the manual segmentations. Precision and Recall scores as mean ± standard deviation for training, validation, and test sets are 0.96 ± 0.05, 0.90 ± 0.18, 0.89 ± 0.15 and 0.97 ±0.03, 0.89± 0.17, 0.90 ± 0.14 respectively. The CNN approach has also been compared to another automatic algorithm, showing better performances. The proposed automatic method provides an accurate estimation of muscle cross-sectional area in muscles with different echogenicity levels.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Redes Neurales de la Computación , Algoritmos , Humanos , Músculo Esquelético/diagnóstico por imagen , Ultrasonografía
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4680-4686, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019038

RESUMEN

Passive elastic elements can contribute to stability, energetic efficiency, and impact absorption in both biological and robotic systems. They also add dynamical complexity which makes them more challenging to model and control. The impact of this added complexity to autonomous learning has not been thoroughly explored. This is especially relevant to tendon-driven limbs whose cables and tendons are inevitably elastic. Here, we explored the efficacy of autonomous learning and control on a simulated bio-plausible tendon-driven leg across different tendon stiffness values. We demonstrate that increasing stiffness of the simulated muscles can require more iterations for the inverse map to converge but can then perform more accurately, especially in discrete tasks. Moreover, the system is robust to subsequent changes in muscle stiffnesses and can adapt on-the-go within 5 attempts. Lastly, we test the system for the functional task of locomotion and found similar effects of muscle stiffness to learning and performance. Given that a range of stiffness values led to improved learning and maximized performance, we conclude the robot bodies and autonomous controllers-at least for tendon-driven systems-can be co-developed to take advantage of elastic elements. Importantly, this opens also the door to development efforts that recapitulate the beneficial aspects of the co-evolution of brains and bodies in vertebrates.


Asunto(s)
Procedimientos Quirúrgicos Robotizados , Robótica , Animales , Elasticidad , Músculo Esquelético , Tendones
11.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4791-4794, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019062

RESUMEN

Surface electromyography (EMG) decomposition techniques have been applied for human-machine interfacing by decoding neural information, while most of decomposition approaches work offline. Here, we apply an online decomposition scheme to decode motor unit activities during three motor tasks, and measure the recognition accuracy of motor type and activation level using the decomposition results. High-density surface EMG signal were recorded from forearm muscles of six able-bodied subjects. The EMG signals were decomposed into motor unit spike trains (MUST) with a sliding window of 100 ms. The computation complexity had time consumption < 50 ms in each window. Most identified motor units discharged during only one motor task. On average, over 5 MUSTs were identified for each motion and the recognition accuracy based on motor unit activities was > 99%. The discharge rate of motor units was highly correlated with the activation level of each motion with an average correlation coefficient of 0.94 ± 0.04. These results indicate the feasibility of an online, multi-motion, and proportional control scheme based on neural decoding in a non-invasive way.


Asunto(s)
Algoritmos , Músculo Esquelético , Electromiografía , Antebrazo , Humanos , Movimiento (Física)
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4799-4802, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019064

RESUMEN

In this paper, we propose the analysis method for finding out the similarity of the muscle force patterns to mine the risk factor of the anterior cruciate ligament (ACL) injury. Akaike information criteria (AIC) under the assumption of the auto-regression model is adapted to analyze the similarities of muscle force patterns in time-series. The difference of AIC values between 2 muscles is considered to be the distance between 2 muscle force patterns and the dexterity of the maneuver is expected to be discussed. We measured drop vertical jump (DVJ) and use the data around the contact timing of whom hadn't had ACL injury experiments. The results showed that we could successfully calculate AIC distance according to the similarity of the time-series data pattern and it can be useful to discuss one's dexterity of controlling body maneuvers soon after contact timing of DVJ motion.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Lesiones del Ligamento Cruzado Anterior/prevención & control , Humanos , Músculo Esquelético , Factores de Riesgo
13.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4803-4806, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019065

RESUMEN

Muscle synergy is the theory that movements are controlled by a module of coordinated combined muscles. This theory is thought to solve the degrees-of-freedom problem in the musculoskeletal system. Previous studies have investigated the robustness of muscle synergies under conditions such as varying speeds and required degrees of accuracy. One of the principles of human movement is that when movement becomes faster, spatial accuracy is reduced. This is called the "speed-accuracy trade-off" (SAT), and many models have been proposed to explain this phenomenon. Studies on muscle synergies have shown that muscle synergy modules are robust against changes in speed; however, the relationship between SAT and motor control by muscle synergies remains unclear. Therefore, we investigated the relationship between changes in spatial accuracy and changes in speed and muscle synergies from measured behavioral data and surface electromyography. This was achieved by performing an isometric contraction task in which subjects exerted a horizontal force with various movement speeds. The results showed that the module structures of muscle synergies were robust against speed changes, and that the neural commands to muscle synergies changed in response to speed changes. In addition, changes in spatial accuracy with variations in speed tended to increase when movement was performed with a single muscle synergy. These results suggest that the number of muscle synergies used for movement may affect movement accuracy.Clinical Relevance-The results of this study suggest that the number of muscle synergies used for movement affects spatial accuracy.


Asunto(s)
Contracción Isométrica , Músculo Esquelético , Electromiografía , Humanos , Movimiento
14.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4819-4822, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019069

RESUMEN

Appropriate regulation of joint impedance is required to successfully navigate our environment. Joint impedance is strongly dependent upon the mechanical properties of the muscles and tendons spanning it. While the impedance of the joint has been well characterized, methods to determine the individual contribution from the muscles and tendons are limited. This is a crucial gap as muscle and tendon impedance can be selectively altered by aging, pathology, or injury. Therefore, we developed an innovative in vivo method that allows for the simultaneous quantification of joint, muscle, and tendon impedance. Stochastic perturbations of ankle angle were applied while a B-mode ultrasound was used to image the displacement of the medial gastrocnemius muscle-tendon junction. Non-parametric system identification was used to quantify ankle impedance and the frequency response function between ankle rotations and muscle-tendon junction displacements. The latter represents, when scaled by Achilles tendon moment arm, the ratio between the net musculotendon impedance and the impedance of the muscle, a relationship we refer to as the impedance ratio. Muscle and tendon impedance can be calculated from these experimental estimates. The ability to simultaneously quantify joint, muscle, and tendon impedance will provide a clearer understanding their respective roles in our ability to navigate our environment, and how changes in those roles may contribute to functional impairments.


Asunto(s)
Tendón Calcáneo , Tobillo , Tendón Calcáneo/diagnóstico por imagen , Articulación del Tobillo/diagnóstico por imagen , Impedancia Eléctrica , Músculo Esquelético
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4854-4857, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019077

RESUMEN

A method for ankle torque prediction ahead of the current time is proposed in this paper. The mean average value of EMG signals from four muscles, alongside the joint angle and angular velocity of the right ankle, were used as input parameters to train a time-delayed artificial neural network. Data collected from five healthy subjects were used to generate the dataset to train and test the model. The model predicted ankle torque for five different future times from zero to 2 seconds. Model predictions were compared to torque calculated from inverse dynamics for each subject. The model predicted ankle torque up to 1 second ahead of time with normalized root mean squared error of less than 15 percent while the coefficient of determination was over 0.85.Clinical Relevance- the potential of the model for predicting joint torque ahead of time is helpful to establish an intuitive interaction between human and assistive robots. This model has application to assist patients with neurological disorders.


Asunto(s)
Tobillo , Músculo Esquelético , Articulación del Tobillo , Humanos , Redes Neurales de la Computación , Torque
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4917-4920, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019091

RESUMEN

Work-related musculoskeletal disorders (MSDs) are a major concern in industries and working environments. They cause not only suffering to the employee and decrease in performance, but also high economic losses to the companies and the society. Workers from assembly lines and machine operators are one of the most frequently affected working population. Moreover, one of the main types of MSDs in occupational environments are shoulder injuries. Exoskeletons have been applied and tested in rehabilitation and they are gaining ground in occupational environments as assistive devices to augment human force and minimize loads on muscles and joints. However, more evidence about the effects of several exoskeletons models in assisting different tasks is needed. We measured shoulder muscles activity (AD - anterior deltoid and MD - medial deltoid) of seven automotive workers using the SuitX® upper limb exoskeleton while performing different screwing tasks, at different shoulder levels while handling different tools. We found significant muscle activity reduction for 2 of the 4 proposed tasks, suggesting a task-specificity effectiveness. Therefore, it seems to be a viable option to reduce muscle effort in certain tasks.


Asunto(s)
Dispositivo Exoesqueleto , Hombro , Fenómenos Biomecánicos , Humanos , Músculo Esquelético , Ocupaciones
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4921-4925, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019092

RESUMEN

Individuals with neurological impairment, particularly those with cervical level spinal cord injuries (SCI), often have difficulty with daily tasks due to triceps weakness or total loss of function. More demanding tasks, such as sit-skiing, may be rendered impossible due to their extreme strength demands. Design of exoskeletons that address this issue by providing supplemental strength in arm extension is an active field of research but commercial devices are not yet available for use. Most current designs employ electric motors that necessitate the addition of bulky power sources and extraneous wiring, rendering the devices impractical in daily life. The possibility of powering an upper extremity exoskeleton passively has been explored, but to date, none have delivered sufficient function or strength to provide useful assistance for sit-skiing. We seek to rectify this with the design of a passively actuated exoskeletal arm brace capable of operating in two, adjustable-strength modes: one for low level gravity compensation to aid in active range of motion, and the other for more stringent weight bearing activities. The mechanism developed through this paper allows for an affordable, lightweight, modular device that can be adjusted and customized for the needs of each individual patient.


Asunto(s)
Dispositivo Exoesqueleto , Brazo , Fenómenos Biomecánicos , Humanos , Músculo Esquelético , Rango del Movimiento Articular
18.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4930-4935, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33019094

RESUMEN

To increase the acceptability of exoskeletons, there is growing attention toward finding an alternative soft actuator that can safely perform at close vicinity of the human body. In this study, we investigated the capability of the dielectric elastomer actuators (DEAs), for muscle-like actuation of rehabilitation robots. First, an artificial skeletal muscle was configured using commercially available stacked DEAs arranged in a 3x4 array of three parallel fibers consisting of four DEAs connected in series. The shortening and force generation capabilities of this artificial muscle were then measured. An alternate 3x5 version of this muscle was mounted on the forearm of an upper extremity phantom model to actuate its elbow joint. The actuation capability of this muscle was then tested under various tensile loads, 1 N to 4 N, placed at the center of mass of the forearm+hand of the phantom model. The active range of motion and angular velocity of the phantom model's tip of the hand were measured using a motion capture system. The 3×4 artificial muscle produced 30.47 N of force and 5.3 mm of maximum shortening. The 3x5 artificial muscle was capable of actuating the elbow flexion 19.5º with 16.2 º/s angular velocity in the sagittal plane, under a 1 N tensile load. The active range of motion was substantially reduced as the tensile loads increased, which limits the capability of these muscles in the current upper extremity exoskeleton design.


Asunto(s)
Articulación del Codo , Dispositivo Exoesqueleto , Niño , Codo , Mano , Humanos , Músculo Esquelético
19.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3771-3774, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018822

RESUMEN

Muscle networks represent a series of interactions among muscles in the central nervous system's effort to reduce the redundancy of the musculoskeletal system in motor-control. How this occurs has only been investigated recently in healthy subjects with a novel technique exploring the functional connectivity between muscles through intermuscular coherence (IMC), yet the potential value of this method in characterizing the alteration of muscular networks after stroke remains unknown. In this study, muscle networks were assessed in post-stroke survivors and healthy controls to identify possible alterations in the neural oscillatory drive to muscles after stroke. Surface electromyography (sEMG) was collected from eight key upper extremity muscles to non-invasively determine the common neural input to the spinal motor neurons innervating muscle fibers. Coherence was computed between all possible muscle pairs and further decomposed by non-negative matrix factorization (NMF) to identify the common spectral patterns of coherence underlying the muscle networks. Results suggested that the number of identified muscle networks during dynamic force generation decreased after stroke. The findings in this study could provide a new prospective for understanding the motor control recovery during post-stroke rehabilitation.


Asunto(s)
Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Humanos , Músculo Esquelético , Estudios Prospectivos , Sobrevivientes
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3775-3778, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-33018823

RESUMEN

By 2020, over 2.2 million people in the United States will be living with an amputated lower limb. The functional impact of amputations presents significant challenges in daily living activities. While significant work has been done to develop smart prosthetics, for the long-term development of effective and robust myoelectric control systems for transtibial amputees, there is still much that needs to be understood regarding how extrinsic muscles of the lower limb are utilized post-amputation. In this study, we examined muscle activity between the intact and residual limbs of three transtibial amputees with the aim of identifying differences in voluntary recruitment patterns during a bilateral motor task. We report that while there is variability across subjects, there are consistencies in the muscle recruitment patterns for the same functional movement between the intact and the residual limb within each subject. These results provide insights for how symmetric activation in residual muscles can be characterized and used to develop myoelectric control strategies for prosthetic devices in transtibial amputees.


Asunto(s)
Amputados , Miembros Artificiales , Tobillo , Fenómenos Biomecánicos , Electromiografía , Humanos , Músculo Esquelético
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