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1.
Medicine (Baltimore) ; 100(9): e24656, 2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-33655929

RESUMEN

INTRODUCTION: To facilitate the command to the learner, therapist can use verbal cues for guidance: internal focus (own body) and external focus (consequence of movement in the environment). OBJECTIVE: To examine the effects of different attentional focus on upper limb motor performance in post-stroke. METHODS: Randomized controlled trial with 2 groups. Study realized at Integrated Clinic of the Faculty of Health Science at Trairi (Santa Cruz, Rio Grande do Norte, Brazil). Twelve participants allocated into 2 groups. Two motor tasks were used: task 1, reach-point; task 2, reach-grasp-fit, with the paretic extremity, using verbal commands directed by a trained therapist. In the first phase, Group 1 received commands with internal focus, while Group 2 was instructed with commands with external focus. After 1 week, the command type was changed between groups. The variables collected was movement time, velocity and number of peaks velocity. RESULTS: Both attentional focus promoted significant differences in movement time and velocity, however, only Internal Focus provided significant results in both tasks of the same variables. DISCUSSION: The benefits of 1 attentional focus on the other are not fully confirmed. However, not receiving any kind of attention guidance compromises motor performance. The results support the hypothesis that the benefits of the External Focus are accentuated when preceded by the Internal Focus. CLINICAL TRIAL REGISTRATION: Research Ethics Committee of the Faculty of Helth Science at Trairi (Facisa - UFRN)- Number CAAE 2.625.609, approved on April 13, 2018; Brazilian Registry of Clinical Trials - RBR-4995cr approved on July 4, 2019 retrospectively registered (http://www.ensaiosclinicos.gov.br/rg/RBR-4995cr/).


Asunto(s)
Atención , Desempeño Psicomotor/fisiología , Rehabilitación de Accidente Cerebrovascular/métodos , Accidente Cerebrovascular/psicología , Extremidad Superior/fisiopatología , Anciano , Brasil , Femenino , Fuerza de la Mano/fisiología , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Proyectos Piloto , Accidente Cerebrovascular/fisiopatología
2.
Acta Psychol (Amst) ; 215: 103273, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33735788

RESUMEN

The learning process of ball juggling is characterized by considerable individual differences in acquired coordination patterns. Previous research has shown that the coordination patterns observed in novice jugglers can be roughly divided into two classes: the high ratio pattern, in which the ball is held for a relatively long time, and the low ratio pattern, in which the ball is held for a relatively short time. To account for these differences in coordination patterns, we examined the anchoring strategies employed by novice jugglers for controlling the juggling movements. Analyses of the correlation between coordination patterns and selected spatiotemporal variabilities revealed that the coordination patterns with a high dwell ratio had lower temporal variability than patterns with a low dwell ratio, which in turn had lower variability of spatial variables than patterns with a high dwell ratio. These findings indicate that individual differences in the coordination patterns adopted by novice jugglers, and hence their learning paths, result from differences in the control strategies employed.


Asunto(s)
Destreza Motora , Desempeño Psicomotor , Humanos , Individualidad , Aprendizaje , Movimiento
3.
Sensors (Basel) ; 21(4)2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33670498

RESUMEN

Currently available jaw motion tracking methods require large accessories mounted on a patient and are utilized in controlled environments, for short-time examinations only. In some cases, especially in the evaluation of bruxism, a non-restrictive, 24-h jaw tracking method is needed. Bruxism oriented, electromyography (EMG)-based devices and sensor-enhanced occlusal splints are able to continuously detect masticatory activity but are uninformative in regards to movement trajectories and kinematics. This study explores a possibility to use a permanent magnet and a 3-axial magnetometer to track the mandible's spatial position in relation to the maxilla. An algorithm for determining the sensor's coordinates from magnetic field values was developed, and it was verified via analytical and finite element modeling and by using a 3D positioning system. Coordinates of the cubic test trajectory (a = 10 mm) were determined with root-mean-square error (RMSE) of 0.328±0.005 mm. Possibility for teeth impact detection by accelerometry was verified. Test on a 6 degrees-of-freedom (DOF), hexapod-based jaw motion simulator moving at natural speed confirmed the system's ability to simultaneously detect jaw position and the impacts of teeth. Small size of MEMS sensors is suitable for a wearable intra-oral system that could allow visualization of continuous jaw movement in 3D models and could enable new research on parafunctional jaw activities.


Asunto(s)
Acelerometría , Maxilares , Movimiento , Fenómenos Biomecánicos , Humanos , Fenómenos Magnéticos , Movimiento (Física)
4.
Sensors (Basel) ; 21(4)2021 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-33671505

RESUMEN

There are few wearable sensors suitable for daily monitoring of wrist and finger movements for hand-related healthcare applications. Here, we describe the development and validation of a novel algorithm for magnetically counting hand movements. We implemented the algorithm on a wristband that senses magnetic field changes produced by movement of a magnetic ring worn on the finger (the "Manumeter"). The "HAND" (Hand Activity estimated by Nonlinear Detection) algorithm assigns a "HAND count" by thresholding the real-time change in magnetic field created by wrist and/or finger movement. We optimized thresholds to achieve a HAND count accuracy of ~85% without requiring subject-specific calibration. Then, we validated the algorithm in a dexterity-impaired population by showing that HAND counts strongly correlate with clinical assessments of upper extremity (UE) function after stroke. Finally, we used HAND counts to test a recent hypothesis in stroke rehabilitation that real-world UE hand use increases only for stroke survivors who achieve a threshold level of UE functional capability. For 29 stroke survivors, HAND counts measured at home did not increase until the participants' Box and Blocks Test scores exceeded ~50% normal. These results show that a threshold-based magnetometry approach can non-obtrusively quantify hand movements without calibration and also verify a key concept of real-world hand use after stroke.


Asunto(s)
Algoritmos , Mano , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Calibración , Femenino , Humanos , Masculino , Movimiento , Accidente Cerebrovascular/diagnóstico , Muñeca
5.
J Neuroeng Rehabil ; 18(1): 47, 2021 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-33691710

RESUMEN

BACKGROUND: While walking, people swing their arms in a specific pattern. This specific arm swing pattern during walking has shown to have a beneficial effect on gait as it reduces walking energy cost and optimizes balance. In several patient populations the arm movements can be directly affected (e.g. in patients with acquired brain injury (ABI)), which in turn has a negative effect on their gait pattern, balance and energy cost of walking. MAIN TEXT: In December 2019, Kahn et al. published a paper in JNER concerning the quantification of upper limb associated reactions (ARs) during walking in people with ABI. ARs are defined as "an effort-dependent phenomenon causing an involuntary increase in upper limb muscle tone, with awkward and uncomfortable postures". These upper limb ARs appear often in patients with ABI and can have an important effect on their gait. The authors calculated kinematic measures using three-dimensional gait analysis relating to range of motion, variability and mean position over the gait cycle for the different upper limb joints (shoulder, elbow, wrist) during self-selected steady-state walking. Based on differences they found between an ABI cohort and healthy control cohort, the authors concluded that they were able to quantify ARs during walking in this population. This calculation, however, is not specific for upper limb ARs. In fact, the authors calculated general measures of arm posture (e.g. mean position over the gait cycle) or arm movement (e.g. range of motion and variability) during gait. Previous research has already indicated that other factors than ARs can influence the posture or movement of the arm during gait in patients with brain injury, such as voluntary compensations for gait instability and contractures or spasticity of upper arm muscles. Yet, it is not possible to disentangle the different causes of the altered arm posture during steady-state walking based on the proposed measures. CONCLUSION: The kinematic arm measures proposed by Kahn et al. (J Neuroeng Rehabil 16(1):160, 2019) are not a direct measure of ARs, but provide a quantification of overall deviation of arm posture or movement during gait. Depending on the specific study design these measures may provide insights in ARs.


Asunto(s)
Lesiones Encefálicas , Caminata , Brazo , Fenómenos Biomecánicos , Marcha , Humanos , Movimiento , Extremidad Superior
6.
Nat Commun ; 12(1): 1682, 2021 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-33727562

RESUMEN

Functional intestinal imaging holds importance for the diagnosis and evaluation of treatment of gastrointestinal diseases. Currently, preclinical imaging of intestinal motility in animal models is performed either invasively with excised intestines or noninvasively under anesthesia, and cannot reveal intestinal dynamics in the awake condition. Capitalizing on near-infrared optics and a high-absorbing contrast agent, we report the Trans-illumination Intestine Projection (TIP) imaging system for free-moving mice. After a complete system evaluation, we performed in vivo studies, and obtained peristalsis and segmentation motor patterns of free-moving mice. We show the in vivo typical segmentation motor pattern, that was previously shown in ex vivo studies to be controlled by intestinal pacemaker cells. We also show the effects of anesthesia on motor patterns, highlighting the possibility to study the role of the extrinsic nervous system in controlling motor patterns, which requires unanesthetized live animals. Combining with light-field technologies, we further demonstrated 3D imaging of intestine in vivo (3D-TIP). Importantly, the added depth information allows us to extract intestines located away from the abdominal wall, and to quantify intestinal motor patterns along different directions. The TIP system should open up avenues for functional imaging of the GI tract in conscious animals in natural physiological states.


Asunto(s)
Motilidad Gastrointestinal/fisiología , Imagenología Tridimensional , Intestinos/diagnóstico por imagen , Intestinos/fisiología , Transiluminación , Anestesia , Animales , Medios de Contraste/química , Femenino , Cabello/diagnóstico por imagen , Humanos , Ratones , Movimiento , Factores de Tiempo
7.
J Prosthodont ; 30(S1): 64-66, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33783092

RESUMEN

PURPOSE: The purpose of this Critically Appraised Topic was to investigate the possible clinical relevance of recording the immediate mandibular lateral translation. MATERIALS AND METHODS: A literature search limited to Clinical trials, Randomized Controlled Trials, Systematic Reviews, Meta Analyses, and using the PICO headings revealed no citations. Using the key words dental, occlusion, immediate side shift, also received no citations. Expanding the search criteria to include Journal Articles revealed 17 citations. Using dental occlusion, Bennett movement, revealed 21 citations. RESULTS: The cited articles were reviewed for relevance and duplicates were eliminated. The resulting 10 English language in vivo studies pertinent to the question were included. Other articles were culled from the author's library and the reference list of the aforementioned articles. There is no evidence on the prevalence of IMLT in patients in need of occlusal rehabilitation. There is agreement that the recording of the IMLT is reference point and recording instrument dependent. There is agreement that IMLT is observable on some patients and is minimal in magnitude. There is no evidence of any adverse clinical events as a result of not including IMLT in a restorative occlusal scheme. CONCLUSIONS: It is justifiable to question the necessity of attempting both to record immediate mandibular lateral translation on the average patient and reproduce it on an articulator.


Asunto(s)
Articuladores Dentales , Mandíbula , Humanos , Movimiento
8.
Sensors (Basel) ; 21(4)2021 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-33672802

RESUMEN

This study investigated the whole-body coordination patterning in successful and faulty spikes using self-organising map-based cluster analysis. Ten young, elite volleyball players (aged 15.5 ± 0.7 years) performed 60 volleyball spikes in a real-game environment. Adopting the cluster analysis, based on a self-organising map, whole-body coordination patterning was explored between successful and faulty spikes of individual players. The self-organising maps (SOMs) portrayed whole body, lower and upper limb coordination dissimilarities during the jump phase and the ball impact phases between the successful and faulty spikes. The cluster analysis illustrated that the whole body, upper limb and lower limb coordination patterning of each individual's successful spikes were similar to their faulty spikes. Range of motion patterning also demonstrated no differences in kinematics between spike outcomes. Further, the upper limb angular velocity patterning of the players' successful/faulty spikes were similar. The SPM analysis portrayed significant differences between the normalized upper limb angular velocities from 35% to 45% and from 76% to 100% of the spike movement. Although the lower limb angular velocities are vital for achieving higher jumps in volleyball spikes, the results of this study portrayed that the upper limb angular velocities distinguish the differences between successful and faulty spikes among the attackers. This confirms the fact that volleyball coaches should shift their focus toward the upper limb velocity and coordination training for higher success rates in spiking for volleyball attackers.


Asunto(s)
Rendimiento Atlético , Voleibol , Adolescente , Fenómenos Biomecánicos , Análisis por Conglomerados , Humanos , Extremidad Inferior , Movimiento , Rango del Movimiento Articular
9.
Sensors (Basel) ; 21(4)2021 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-33673141

RESUMEN

(1) Background: Three-dimensional (3-D) hand position is one of the kinematic parameters that can be inferred from Electromyography (EMG) signals. The inferred parameter is used as a communication channel in human-robot collaboration applications. Although its application from the perspective of rehabilitation and assistive technologies are widely studied, there are few papers on its application involving healthy subjects such as intelligent manufacturing and skill transfer. In this regard, for tasks associated with complex hand trajectories without the consideration of the degree of freedom (DOF), the prediction of 3-D hand position from EMG signal alone has not been addressed. (2) Objective: The primary aim of this study is to propose a model to predict human motor intention that can be used as information from human to robot. Therefore, the prediction of a 3-D hand position directly from the EMG signal for complex trajectories of hand movement, without the direct consideration of joint movements, is studied. In addition, the effects of slow and fast motions on the accuracy of the prediction model are analyzed. (3) Methods: This study used the EMG signal that is collected from the upper limb of healthy subjects, and the position signal of the hand while the subjects manipulate complex trajectories. We considered and analyzed two types of tasks with complex trajectories, each with quick and slow motions. A recurrent fuzzy neural network (RFNN) model was constructed to predict the 3-D position of the hand from the features of EMG signals alone. We used the Pearson correlation coefficient (CC) and normalized root mean square error (NRMSE) as performance metrics. (4) Results: We found that 3-D hand positions of the complex movement can be predicted with the mean performance of CC = 0.85 and NRMSE = 0.105. The 3-D hand position can be predicted well within a future time of 250 ms, from the EMG signal alone. Even though tasks performed under quick motion had a better prediction performance; the statistical difference in the accuracy of prediction between quick and slow motion was insignificant. Concerning the prediction model, we found that RFNN has a good performance in decoding for the time-varying system. (5) Conclusions: In this paper, irrespective of the speed of the motion, the 3-D hand position is predicted from the EMG signal alone. The proposed approach can be used in human-robot collaboration applications to enhance the natural interaction between a human and a robot.


Asunto(s)
Electromiografía , Mano , Intención , Robótica , Humanos , Movimiento
10.
Phys Rev Lett ; 126(8): 088003, 2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-33709750

RESUMEN

Helical swimming is a ubiquitous strategy for motile cells to generate self-gradients for environmental sensing. The model biflagellate Chlamydomonas reinhardtii rotates at a constant 1-2 Hz as it swims, but the mechanism is unclear. Here, we show unequivocally that the rolling motion derives from a persistent, nonplanar flagellar beat pattern. This is revealed by high-speed imaging and micromanipulation of live cells. We construct a fully 3D model to relate flagellar beating directly to the free-swimming trajectories. For realistic geometries, the model reproduces both the sense and magnitude of the axial rotation of live cells. We show that helical swimming requires further symmetry breaking between the two flagella. These functional differences underlie all tactic responses, particularly phototaxis. We propose a control strategy by which cells steer toward or away from light by modulating the sign of biflagellar dominance.


Asunto(s)
Flagelos/fisiología , Modelos Biológicos , Chlamydomonas reinhardtii/fisiología , Movimiento/fisiología , Natación
11.
Geospat Health ; 16(1)2021 03 11.
Artículo en Inglés | MEDLINE | ID: mdl-33706497

RESUMEN

Mobility of individuals and their physical social networks are the root causes for the spread of current coronavirus pandemic. We propose here a method of visualizing the spatial and chronological aspects of the spread of this virus based on geographical information systems (GIS) and Gephi graphs. For this approach we used qualitative data from newspaper reports and prepared layouts varying from macro to micro scales that show that this approach can enrich traditional GIS approaches, thereby assisting mobility planners and policymakers.


Asunto(s)
Sistemas de Información Geográfica , Pandemias , Humanos , India/epidemiología , Movimiento
12.
Sensors (Basel) ; 21(5)2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33668229

RESUMEN

Stroke is a cerebrovascular disease (CVD), which results in hemiplegia, paralysis, or death. Conventionally, a stroke patient requires prolonged sessions with physical therapists for the recovery of motor function. Various home-based rehabilitative devices are also available for upper limbs and require minimal or no assistance from a physiotherapist. However, there is no clinically proven device available for functional recovery of a lower limb. In this study, we explored the potential use of surface electromyography (sEMG) as a controlling mechanism for the development of a home-based lower limb rehabilitative device for stroke patients. In this experiment, three channels of sEMG were used to record data from 11 stroke patients while performing ankle joint movements. The movements were then decoded from the sEMG data and their correlation with the level of motor impairment was investigated. The impairment level was quantified using the Fugl-Meyer Assessment (FMA) scale. During the analysis, Hudgins time-domain features were extracted and classified using linear discriminant analysis (LDA) and artificial neural network (ANN). On average, 63.86% ± 4.3% and 67.1% ± 7.9% of the movements were accurately classified in an offline analysis by LDA and ANN, respectively. We found that in both classifiers, some motions outperformed others (p < 0.001 for LDA and p = 0.014 for ANN). The Spearman correlation (ρ) was calculated between the FMA scores and classification accuracies. The results indicate that there is a moderately positive correlation (ρ = 0.75 for LDA and ρ = 0.55 for ANN) between the two of them. The findings of this study suggest that a home-based EMG system can be developed to provide customized therapy for the improvement of functional lower limb motion in stroke patients.


Asunto(s)
Articulación del Tobillo , Electromiografía , Movimiento , Rehabilitación de Accidente Cerebrovascular/instrumentación , Accidente Cerebrovascular/terapia , Humanos
13.
Med Probl Perform Art ; 36(1): 1-9, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33647091

RESUMEN

OBJECTIVE: Musician's dystonia represents a special case of focal dystonia. It is described as a task-specific movement disorder which presents itself as muscular incoordination or loss of voluntary fine-motor control of extensively trained movements while a musician is playing the instrument. Several triggering factors have been identified, such as overuse, chronic pain, perfectionism, and anxiety disorders. As a common feature, dysfunctional self-management and stress-coping mechanisms are at the root of the aforementioned behaviors. Based on long-term experience from our musicians' medicine outpatient clinic, we hypothesized that early psychic or somatic traumatization may be an underlying mechanism and therefore contribute essentially to focal dystonia. METHODS: In a qualitative study, we investigated the role of early traumatization as a potential cause of motor failures, such as musician's dystonia, employing an episodic interview on a sample of six professional musicians (age 30-57 yrs, 5:1 M:F) suffering from musician's dystonia. RESULTS: Using grounded theory methodology, we were able to derive one generalized etiological model describing contributing factors in the etiological understanding of focal dystonia from the six case studies. The qualitative interviews clearly revealed that all patients experienced early psychic traumatizations, including violence and parents' substance abuse. CONCLUSIONS: In this small sample, we theorize that in-depth, early traumatization most probably led to a dysfunctional stress-coping mechanism. We therefore propose in our model that there are two types of motor failures, one linked to stressful experiences, dysfunctional coping behaviors, and increased muscle tone, and one linked to genetic susceptibility of the motor-system without psychological triggering factors.


Asunto(s)
Distonía , Trastornos Distónicos , Música , Adaptación Psicológica , Adulto , Humanos , Persona de Mediana Edad , Movimiento
14.
Sensors (Basel) ; 21(3)2021 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-33540570

RESUMEN

Parkinson's disease patients face numerous motor symptoms that eventually make their life different from those of normal healthy controls. Out of these motor symptoms, tremor and bradykinesia, are relatively prevalent in all stages of this disease. The assessment of these symptoms is usually performed by traditional methods where the accuracy of results is still an open question. This research proposed a solution for an objective assessment of tremor and bradykinesia in subjects with PD (10 older adults aged greater than 60 years with tremor and 10 older adults aged greater than 60 years with bradykinesia) and 20 healthy older adults aged greater than 60 years. Physical movements were recorded by means of an AWEAR bracelet developed using inertial sensors, i.e., 3D accelerometer and gyroscope. Participants performed upper extremities motor activities as adopted by neurologists during the clinical assessment based on Unified Parkinson's Disease Rating Scale (UPDRS). For discriminating the patients from healthy controls, temporal and spectral features were extracted, out of which non-linear temporal and spectral features show greater difference. Both supervised and unsupervised machine learning classifiers provide good results. Out of 40 individuals, neural net clustering discriminated 34 individuals in correct classes, while the KNN approach discriminated 91.7% accurately. In a clinical environment, the doctor can use the device to comprehend the tremor and bradykinesia of patients quickly and with higher accuracy.


Asunto(s)
Hipocinesia , Monitoreo Fisiológico , Enfermedad de Parkinson , Dispositivos Electrónicos Vestibles , Anciano , Humanos , Hipocinesia/diagnóstico , Movimiento , Enfermedad de Parkinson/diagnóstico , Temblor/diagnóstico
15.
Sensors (Basel) ; 21(3)2021 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-33540608

RESUMEN

Research from psychology has suggested that body movement may directly activate emotional experiences. Movement-based emotion regulation is the most readily available but often underutilized strategy for emotion regulation. This research aims to investigate the emotional effects of movement-based interaction and its sensory feedback mechanisms. To this end, we developed a smart clothing prototype, E-motionWear, which reacts to four movements (elbow flexion/extension, shoulder flexion/extension, open and closed arms, neck flexion/extension), fabric-based detection sensors, and three-movement feedback mechanisms (audio, visual and vibrotactile). An experiment was conducted using a combined qualitative and quantitative approach to collect participants' objective and subjective emotional feelings. Results indicate that there was no interaction effect between movement and feedback mechanism on the final emotional results. Participants preferred vibrotactile and audio feedback rather than visual feedback when performing these four kinds of upper body movements. Shoulder flexion/extension and open-closed arm movements were more effective for improving positive emotion than elbow flexion/extension movements. Participants thought that the E-motionWear prototype were comfortable to wear and brought them new emotional experiences. From these results, a set of guidelines were derived that can help frame the design and use of smart clothing to support users' emotional regulation.


Asunto(s)
Articulación del Codo , Regulación Emocional , Textiles , Adolescente , Adulto , Brazo , Femenino , Humanos , Masculino , Movimiento , Adulto Joven
16.
Sensors (Basel) ; 21(3)2021 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-33540791

RESUMEN

RGB-D cameras have been commercialized, and many applications using them have been proposed. In this paper, we propose a robust registration method of multiple RGB-D cameras. We use a human body tracking system provided by Azure Kinect SDK to estimate a coarse global registration between cameras. As this coarse global registration has some error, we refine it using feature matching. However, the matched feature pairs include mismatches, hindering good performance. Therefore, we propose a registration refinement procedure that removes these mismatches and uses the global registration. In an experiment, the ratio of inliers among the matched features is greater than 95% for all tested feature matchers. Thus, we experimentally confirm that mismatches can be eliminated via the proposed method even in difficult situations and that a more precise global registration of RGB-D cameras can be obtained.


Asunto(s)
Monitoreo Fisiológico , Calibración , Humanos , Movimiento
17.
Am J Phys Med Rehabil ; 100(3): 235-242, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33595935

RESUMEN

OBJECTIVE: The aims of this study were to (1) evaluate the relationships between stationary and dynamic associated reaction (AR) tests in people with acquired brain injury using surface electromyography (sEMG) muscle activity and three-dimensional motion analysis kinematic measures and (2) assess the test-retest reliability of sEMG and seated tests of ARs. DESIGN: Forty-two adults with acquired brain injury underwent AR testing with seated contralateral maximal voluntary isometric contraction tests and walking (self-selected and fast speeds). Associated reaction measurements included biceps brachii sEMG, elbow goniometry, and three-dimensional motion analysis kinematics during walking. Pearson correlations evaluated the relationships between seated and dynamic walking AR tests and between muscle activity and kinematic measures. Chronic participants were reassessed 1 wk later for reliability. RESULTS: A strong (r = 0.65) and moderate (r = 0.53) relationship existed for biceps brachii sEMG during seated and walking tests at self-selected and fast walk, respectively. A weak to moderate relationship existed between biceps brachii sEMG and kinematics during walking and between seated and walking measures of ARs (r = 0.23-0.53). All tests had strong to very strong test-retest reliability (intraclass correlation coefficients, >0.78). CONCLUSION: Seated contralateral maximal voluntary isometric contraction tests correlate only weakly to moderately with AR walking kinematics and moderately to strongly with biceps brachii activation during walking. Moderate relationships exist between sEMG and kinematics, indicating that they may provide different information for ARs.


Asunto(s)
Lesiones Encefálicas/fisiopatología , Trastornos Neurológicos de la Marcha/fisiopatología , Contracción Isométrica/fisiología , Movimiento/fisiología , Músculo Esquelético/fisiopatología , Sedestación , Extremidad Superior/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Electromiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Rango del Movimiento Articular , Reproducibilidad de los Resultados , Adulto Joven
18.
Nat Neurosci ; 24(3): 412-424, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33619403

RESUMEN

Rapid execution of motor sequences is believed to depend on fusing movement elements into cohesive units that are executed holistically. We sought to determine the contribution of primary motor and dorsal premotor cortex to this ability. Monkeys performed highly practiced two-reach sequences, interleaved with matched reaches performed alone or separated by a delay. We partitioned neural population activity into components pertaining to preparation, initiation and execution. The hypothesis that movement elements fuse makes specific predictions regarding all three forms of activity. We observed none of these predicted effects. Rapid two-reach sequences involved the same set of neural events as individual reaches but with preparation for the second reach occurring as the first was in flight. Thus, at the level of dorsal premotor and primary motor cortex, skillfully executing a rapid sequence depends not on fusing elements, but on the ability to perform two key processes at the same time.


Asunto(s)
Corteza Motora/fisiología , Movimiento/fisiología , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Animales , Macaca mulatta , Masculino
19.
Phys Ther Sport ; 48: 209-218, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33529930

RESUMEN

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction has a detrimental impact on athletic performance. Despite rehabilitation guidelines and criterion-based progressions to ensure safe restoration of fundamental physical capacities and maladaptive movement strategies, residual deficits in maximal strength, rate of force development (RFD), power and reactive strength are commonly reported. These combined with associated compensatory inter and intra-limb strategies increase the risk of re-injury. OBJECTIVE: The aim of this article is to examine the relationships between fundamental physical capacities and biomechanical variables during dynamic movement tasks. DESIGN: Narrative review. RESULTS: The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts in the later stages of rehabilitation and RTS CONCLUSION: The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts in the later stages of rehabilitation and RTS.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior/fisiopatología , Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior/rehabilitación , Traumatismos en Atletas/fisiopatología , Traumatismos en Atletas/cirugía , Fuerza Muscular , Músculo Cuádriceps/fisiología , Fenómenos Biomecánicos , Humanos , Movimiento , Volver al Deporte , Torque
20.
Nature ; 590(7844): 80-84, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33536650

RESUMEN

Active matter consists of units that generate mechanical work by consuming energy1. Examples include living systems (such as assemblies of bacteria2-5 and biological tissues6,7), biopolymers driven by molecular motors8-11 and suspensions of synthetic self-propelled particles12-14. A central goal is to understand and control the self-organization of active assemblies in space and time. Most active systems exhibit either spatial order mediated by interactions that coordinate the spatial structure and the motion of active agents12,14,15 or the temporal synchronization of individual oscillatory dynamics2. The simultaneous control of spatial and temporal organization is more challenging and generally requires complex interactions, such as reaction-diffusion hierarchies16 or genetically engineered cellular circuits2. Here we report a simple technique to simultaneously control the spatial and temporal self-organization of bacterial active matter. We confine dense active suspensions of Escherichia coli cells and manipulate a single macroscopic parameter-namely, the viscoelasticity of the suspending fluid- through the addition of purified genomic DNA. This reveals self-driven spatial and temporal organization in the form of a millimetre-scale rotating vortex with periodically oscillating global chirality of tunable frequency, reminiscent of a torsional pendulum. By combining experiments with an active-matter model, we explain this behaviour in terms of the interplay between active forcing and viscoelastic stress relaxation. Our findings provide insight into the influence of bacterial motile behaviour in complex fluids, which may be of interest in health- and ecology-related research, and demonstrate experimentally that rheological properties can be harnessed to control active-matter flows17,18. We envisage that our millimetre-scale, tunable, self-oscillating bacterial vortex may be coupled to actuation systems to act a 'clock generator' capable of providing timing signals for rhythmic locomotion of soft robots and for programmed microfluidic pumping19, for example, by triggering the action of a shift register in soft-robotic logic devices20.


Asunto(s)
Escherichia coli/fisiología , Reología , Análisis Espacio-Temporal , Sustancias Viscoelásticas/química , Sustancias Viscoelásticas/metabolismo , ADN Bacteriano/análisis , ADN Bacteriano/química , Difusión , Escherichia coli/citología , Escherichia coli/aislamiento & purificación , Microfluídica , Peso Molecular , Movimiento , Robótica , Suspensiones
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