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1.
Apunts, Med. esport (Internet) ; 55(206): 63-70, abr.-jun. 2020. tab, graf
Artículo en Inglés | IBECS | ID: ibc-ET2-5893

RESUMEN

INTRODUCTION: The ACL injury is considered one of the most serious injuries and usually occurs in actions that include movements with changes of direction, jump and landing. It is a common injury between the young active population and the risk in women of suffering from non-contact injury is superior to that of men. Athletes who suffer from non-contact injuries of the ACL usually have common biomechanical profiles, with landings with large values in ground reaction force (GRF) and therefore, low cushioning on landing. OBJECTIVE: To determine possible correlations between GRF and muscular activation at lading after a jump. MATERIAL AND METHODS: The type of study carried out is an observational study in which, using surface electromyography (EMG), a force platform and an electrogoniometer, the aim is to assess muscle activation and its relationship with GRF (specifically the vertical component Fz). RESULTS: Correlations have been observed between the reaction force of the soil (Fz) in the moments where the reaction force of the soil is greater and the instant where the knee reaches maximum flexion after landing, with the activation of certain muscle groups and differences depending on the gender of the subject. DISCUSSION: The neuromuscular recruitment strategies in the phases of maximum GRF load and knee flexion are different depending on the sex of the individual, so it should be considered when scheduling prevention and recovery work. CONCLUSION: The evaluation of GRF and muscle activation patterns, allows to assess the dynamics of landing after a jump and to be able to detect different patterns according to sex, with the consequent importance that it can have in the injury mechanism


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Asunto(s)
Humanos , Masculino , Femenino , Adulto , Músculos/fisiología , Movimiento/fisiología , Lesiones del Ligamento Cruzado Anterior , Unión Neuromuscular/fisiología , Fuerza Muscular/fisiología , Electromiografía , Articulación de la Rodilla/fisiopatología , Fenómenos Biomecánicos
2.
Int. j. morphol ; 38(3): 731-736, June 2020. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1098313

RESUMEN

Regardless of sex or body size, police tasks may require officers to change direction speed (CODS) under occupational loads. The purpose of this study was to investigate body composition and CODS in female and male police cadets in both unloaded and occupationally loaded conditions. Body composition and CODS of 51 female (FPC) and 70 male police cadets (MPC) were assessed. Six body composition indices were used: Body mass index (BMI), percent body fat (PBF), percent of skeletal muscle mass (PSMM), protein fat index (PFI), index of hypokinesia (IH), and skeletal muscle mass index (SMMI). The CODS was assessed by Illinois Agility Test (IAT) and IAT while carrying a 10-kg load (LIAT). An independent sample t-test was used to identify the differences between the sexes. The regression determined associations between body composition and LIAT. The alpha level was set at p < 0.05 a priori. MPC had significantly higher (p < 0.001) BMI, PSMM, PFI and SMMI and lower PBF and IH than FPC. MPC were also faster in IAT and LIAT, carrying lower relative loads that imparted less of an impact on CODS performance. Body composition was strongly associated with the time to complete LIAT (R2 = 0.671, p < 0.001). Difference in relative load and body composition influenced CODS performance in both unloaded and loaded conditions. Thus, optimizing body composition through increasing skeletal muscle mass and reducing fat mass could positively influence unloaded and loaded CODS performance and improve elements of police task performance.


El trabajo policial puede requerir que los oficiales cambien la velocidad de dirección (CVD) bajo cargas ocupacionales, indistintamente del sexo o tamaño corporal. El propósito de este estudio fue investigar la composición corporal y los CVD en cadetes de policía de ambos sexos, tanto en condiciones de descarga como de trabajo. Se evaluaron la composición corporal y los CVD de 51 mujeres (CPF) y 70 cadetes de policía masculinos (CPM). Se utilizaron seis índices de composición corporal: índice de masa corporal (IMC), porcentaje de grasa corporal (PGC), porcentaje de masa muscular esquelética (PMME), índice de grasa proteica (IGP), índice de hipocinesia (IH) e índice de masa muscular esquelética (IMME). El CVD fue evaluado por Illinois Agility Test (IAT) y IAT mientras transportaba una carga de 10 kg (LIAT). Se usó una prueba t de muestra independiente para identificar las diferencias entre los sexos. La regresión determinó asociaciones entre la composición corporal y LIAT. El nivel alfa se estableció en p <0,05 a priori. CPM registraron un IMC, PMME, PGC y IMME significativamente más altos (p <0,001) y PGC e IH más bajos que las mujeres (CPF). Los CPM también fueron más rápidos en IAT y LIAT, llevando cargas más bajas, las que tuvieron un impacto menor en el rendimiento de CVD. La composición corporal estaba asociada con el tiempo para completar LIAT (R2 = 0,671, p <0,001). La diferencia en la carga relativa y la composición corporal influyeron en el rendimiento de CVD tanto en condiciones descargadas como cargadas. Por lo tanto, la optimización de la composición corporal a través del aumento de la masa del músculo esquelético, y la reducción de la masa grasa podrían influir de manera positiva en el rendimiento de CVD descargados y cargados, mejorando el rendimiento del trabajo policial.


Asunto(s)
Humanos , Masculino , Femenino , Adulto Joven , Composición Corporal , Caracteres Sexuales , Policia , Movimiento/fisiología , Índice de Masa Corporal , Modelos Logísticos , Factores Sexuales , Tejido Adiposo , Carga de Trabajo
4.
PLoS One ; 15(4): e0231142, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32271802

RESUMEN

Information on the spatial ecology of reef sharks is critical to understanding life-history patterns, yet gaps remain in our knowledge of how these species move and occupy space. Previous studies have focused on offshore reefs and atolls with little information available on the movement and space use of sharks utilising reef habitats closer to shore. Cross-shelf differences in physical and biological properties of reefs can alter regional ecosystem processes resulting in different movement patterns for resident sharks. Passive acoustic telemetry was used to examine residency, space use and depth use of 40 blacktip reef sharks, Carcharhinus melanopterus, on an inshore reef in Queensland, Australia, and assess temporal or biological influences. All sharks showed strong site-attachment to inshore reefs with residency highest among adult females. Sharks exhibited a sex-based, seasonal pattern in space use where males moved more, occupied more space and explored new areas during the reproductive season, while females utilised the same amount of space throughout the year, but shifted the location of the space used. A positive relationship was also observed between space use and size. There was evidence of seasonal site fidelity and long-distance movement with the coordinated, annual migration of two adult males to the study site during the mating season. Depth use was segregated with some small sharks occupying shallower depths than adults throughout the day and year, most likely as refuge from predation. Results highlight the importance of inshore reef habitats to blacktip reef sharks and provide evidence of connectivity with offshore reefs, at least for adult males.


Asunto(s)
Arrecifes de Coral , Movimiento/fisiología , Caracteres Sexuales , Tiburones/fisiología , Acústica , Animales , Femenino , Geografía , Islas , Masculino , Modelos Biológicos , Queensland , Factores de Tiempo
5.
Proc Natl Acad Sci U S A ; 117(18): 10024-10034, 2020 05 05.
Artículo en Inglés | MEDLINE | ID: mdl-32303656

RESUMEN

Sleep pressure and sleep depth are key regulators of wake and sleep. Current methods of measuring these parameters in Drosophila melanogaster have low temporal resolution and/or require disrupting sleep. Here we report analysis tools for high-resolution, noninvasive measurement of sleep pressure and depth from movement data. Probability of initiating activity, P(Wake), measures sleep depth while probability of ceasing activity, P(Doze), measures sleep pressure. In vivo and computational analyses show that P(Wake) and P(Doze) are largely independent and control the amount of total sleep. We also develop a Hidden Markov Model that allows visualization of distinct sleep/wake substates. These hidden states have a predictable relationship with P(Doze) and P(Wake), suggesting that the methods capture the same behaviors. Importantly, we demonstrate that both the Doze/Wake probabilities and the sleep/wake substates are tied to specific biological processes. These metrics provide greater mechanistic insight into behavior than measuring the amount of sleep alone.


Asunto(s)
Ritmo Circadiano/fisiología , Drosophila melanogaster/fisiología , Sueño/fisiología , Vigilia/fisiología , Animales , Conducta Animal/fisiología , Humanos , Modelos Estadísticos , Movimiento/fisiología
6.
J Vis ; 20(3): 8, 2020 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-32232376

RESUMEN

Affordance-based control and current-future control offer competing theoretical accounts of the visual control of locomotion. The aim of this study was to test predictions derived from these accounts about the necessity of self-motion (Experiment 1) and target-ground contact (Experiment 2) in perceiving whether a moving target can be intercepted before it reaches an escape zone. We designed a novel interception task wherein the ability to perceive target catchability before initiating movement was advantageous. Subjects pursued a target moving through a field in a virtual environment and attempted to intercept the target before it escaped into a forest. Targets were catchable on some trials but not others. If subjects perceived that they could not reach the target, they were instructed to immediately give up by pressing a button. After each trial, subjects received a point reward that incentivized them to pursue only those targets that were catchable. On the majority of trials, subjects either pursued and successfully intercepted the target or chose not to pursue at all, demonstrating that humans are sensitive to catchability while stationary. Performance also degraded when the target was floating rather than in contact with the ground. Both findings are incompatible with the current-future account and support the affordance-based account of choosing whether to pursue moving targets.


Asunto(s)
Toma de Decisiones/fisiología , Percepción de Movimiento/fisiología , Desempeño Psicomotor/fisiología , Adolescente , Femenino , Humanos , Masculino , Movimiento/fisiología , Adulto Joven
7.
Phys Ther ; 100(5): 747-756, 2020 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-32339243

RESUMEN

Beth E. Fisher, PT, PhD, FAPTA, is a physical therapist, educator, and scholar whose clinical career has been shaped by numerous observations and experiences of patients' remarkable potential to recover ideal movement capability. Currently, Dr Fisher is a Professor of Clinical Physical Therapy in the Division of Biokinesiology and Physical Therapy at the University of Southern California. She is Director of the Neuroplasticity and Imaging Laboratory, primarily using transcranial magnetic stimulation to investigate brain-behavior relationships during motor skill learning and motor control in both individuals without disabilities and individuals with neurologic disorders. Dr Fisher previously worked at Rancho Los Amigos Medical Center on the Adult Neurology and Brain Injury Services. During her years as a clinician and rehabilitation specialist, it was her greatest ambition to be a part of developing physical therapist interventions that would maximize neural and behavioral recovery in individuals with pathological conditions affecting the nervous system. Toward this goal, she has continued to consult and teach nationally and internationally on current concepts for the treatment of adults with neurological disorders. It has been her consistent clinical observation not only that patients are limited by impairments that result from their injury, but that movement abnormalities are in part the result of a patient's automatic, implicit tendency to "respond" to those impairments via compensation.


Asunto(s)
Lesiones Encefálicas/rehabilitación , Movimiento/fisiología , Enfermedades del Sistema Nervioso/rehabilitación , Plasticidad Neuronal/fisiología , Fisioterapeutas/tendencias , Encéfalo/fisiopatología , Humanos
8.
PLoS One ; 15(3): e0228865, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32150545

RESUMEN

Hunting can be used as a tool for wildlife management, through limitation of population densities and dissuading game from using sensitive areas. The success of these approaches requires in depth knowledge of prey movement. Indeed, movement decisions of game during hunting may affect the killing success of hunters as well as the subsequent location of surviving animals. We thus investigated red deer movement responses to drive hunts and their causal factors. We studied 34 hunting events in the National Estate of Chambord (France) and thereby provided a fine-scale characterization of the immediate and delayed movement responses of red deer to drive hunts. Red deer responded to drive hunts either by immediately fleeing the hunted area, or by initially remaining before ultimately fleeing after the hunters had departed. A few hours after the hunt, all individuals were located in distant areas (> 2 kilometres) from the hunted area. Immediate flight responses were less common when drive hunts occurred in areas with dense understorey. However, neither beater/dog densities nor site familiarity influenced the immediate flight decision. Following a drive hunt, red deer remained outside the hunted areas for periods twice as long compared to periods when no hunting occurred (34 hours vs. 17 hours). Such knowledge of game movement rates in response to drive hunts may help the development of informed management policy for hunted red deer populations.


Asunto(s)
Ciervos/fisiología , Movimiento/fisiología , Animales , Conducta Animal , Femenino , Masculino , Tecnología de Sensores Remotos , Caracteres Sexuales
9.
PLoS One ; 15(3): e0230184, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32182270

RESUMEN

The left and right foot representation area is located within the interhemispheric fissure of the sensorimotor cortex and share spatial proximity. This makes it difficult to visualize the cortical lateralization of event-related (de)synchronization (ERD/ERS) during left and right foot motor imageries. The aim of this study is to investigate the possibility of using ERD/ERS in the mu, low beta, and high beta bandwidth, during left and right foot dorsiflexion kinaesthetic motor imageries (KMI), as unilateral control commands for a brain-computer interface (BCI). EEG was recorded from nine healthy participants during cue-based left-right foot dorsiflexion KMI tasks. The features were analysed for common average and bipolar references. With each reference, mu and beta band-power features were analysed using time-frequency (TF) maps, scalp topographies, and average time course for ERD/ERS. The cortical lateralization of ERD/ERS, during left and right foot KMI, was confirmed. Statistically significant features were classified using LDA, SVM, and KNN model, and evaluated using the area under ROC curves. An increase in high beta power following the end of KMI for both tasks was recorded, from right and left hemispheres, respectively, at the vertex. The single trial analysis and classification models resulted in high discrimination accuracies, i.e. maximum 83.4% for beta ERS, 79.1% for beta ERD, and 74.0% for mu ERD. With each model the features performed above the statistical chance level of 2-class discrimination for a BCI. Our findings indicate these features can evoke left-right differences in single EEG trials. This suggests that any BCI employing unilateral foot KMI can attain classification accuracy suitable for practical implementation. Given results stipulate the novel utilization of mu and beta as independent control features for discrimination of bilateral foot KMI in a BCI.


Asunto(s)
Sincronización Cortical/fisiología , Pie/fisiología , Cinestesia/fisiología , Movimiento/fisiología , Adulto , Interfaces Cerebro-Computador , Electroencefalografía/métodos , Femenino , Lateralidad Funcional/fisiología , Humanos , Imágenes en Psicoterapia/métodos , Imaginación/fisiología , Masculino , Desempeño Psicomotor/fisiología , Adulto Joven
10.
J Sports Sci ; 38(10): 1096-1104, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32178581

RESUMEN

This study aimed to describe stationary overhead throwing biomechanics in South African cricketers, considering playing level, and relative to baseball. Kinematics and ground reaction forces were collected during throwing trials. Inverse dynamics was used to calculate joint kinetics. Inter-subject variability was calculated using the coefficient of variance. A one-dimensional statistical parametric mapping ANOVA was conducted to assess differences between the kinematic waveforms in elite and amateur cricketers (p < 0.05). Fifteen cricketers (elite = 8; amateur = 7) participated in this study. The basic parameters of a cricketer's throwing action are described. Substantial inter-subject variability was noted for all variables, except lumbopelvic movement. Cricketers presented with 74.9 ± 27.3° glenohumeral external rotation and 94.8 ± 23.7° elbow flexion, at maximum external rotation (MER). Amateur cricketers displayed decreased elbow flexion range of motion between 2-14% of the throwing cycle (F = 9.365;p = 0.01); greater shoulder (121.0vs85.9 N; F = 0.36,p = 0.021) and elbow compression (105.6vs72.8 N;F = 0.007,p = 0.043), and superior shoulder force (203.1vs115.5 N;F = 2.43,p = 0.022) at MER, when compared with elite cricketers. Cricketers display similarities to baseball pitchers when throwing overhead from a stationary position. The "preparatory arc" utilised is different to the wind-up noted for baseball. The forces exerted on the shoulder and elbow, in amateur cricketers specifically, are substantially greater at MER and may indicate the potential risk for injury.


Asunto(s)
Cricket/fisiología , Extremidad Superior/fisiología , Adulto , Brazo/fisiología , Fenómenos Biomecánicos , Codo/fisiología , Humanos , Región Lumbosacra/fisiología , Masculino , Movimiento/fisiología , Pelvis/fisiología , Rango del Movimiento Articular , Hombro/fisiología , Estudios de Tiempo y Movimiento , Adulto Joven
11.
Proc Natl Acad Sci U S A ; 117(14): 8135-8142, 2020 04 07.
Artículo en Inglés | MEDLINE | ID: mdl-32205442

RESUMEN

Many studies have demonstrated covariation between muscle activations during behavior, suggesting that muscles are not controlled independently. According to one common proposal, this covariation reflects simplification of task performance by the nervous system so that muscles with similar contributions to task variables are controlled together. Alternatively, this covariation might reflect regulation of low-level aspects of movements that are common across tasks, such as stresses within joints. We examined these issues by analyzing covariation patterns in quadriceps muscle activity during locomotion in rats. The three monoarticular quadriceps muscles (vastus medialis [VM], vastus lateralis [VL], and vastus intermedius [VI]) produce knee extension and so have identical contributions to task performance; the biarticular rectus femoris (RF) produces an additional hip flexion. Consistent with the proposal that muscle covariation is related to similarity of muscle actions on task variables, we found that the covariation between VM and VL was stronger than their covariations with RF. However, covariation between VM and VL was also stronger than their covariations with VI. Since all vastii have identical actions on task variables, this finding suggests that covariation between muscle activity is not solely driven by simplification of overt task performance. Instead, the preferentially strong covariation between VM and VL is consistent with the control of internal joint stresses: Since VM and VL produce opposing mediolateral forces on the patella, the high positive correlation between their activation minimizes the net mediolateral patellar force. These results provide important insights into the interpretation of muscle covariations and their role in movement control.


Asunto(s)
Contracción Isométrica/fisiología , Articulaciones/fisiología , Modelos Neurológicos , Movimiento/fisiología , Músculo Cuádriceps/inervación , Animales , Fenómenos Biomecánicos , Electrodos Implantados , Electromiografía/instrumentación , Femenino , Miembro Posterior/inervación , Miembro Posterior/fisiología , Modelos Lineales , Músculo Cuádriceps/fisiología , Ratas
12.
PLoS One ; 15(3): e0229690, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32134966

RESUMEN

Pedestrian dynamics models the walking movement of individuals in a crowd. It has recently been used in the analysis of procedures to reduce the risk of disease spread in airplanes, relying on the SPED model. This is a social force model inspired by molecular dynamics; pedestrians are treated as point particles, and their trajectories are determined in a simulation. A parameter sweep is performed to address uncertainties in human behavior, which requires a large number of simulations. The SPED model's slow speed is a bottleneck to performing a large parameter sweep. This is a severe impediment to delivering real-time results, which are often required in the course of decision meetings, especially during emergencies. We propose a new model, called CALM, to remove this limitation. It is designed to simulate a crowd's movement in constrained linear passageways, such as inside an aircraft. We show that CALM yields realistic results while improving performance by two orders of magnitude over the SPED model.


Asunto(s)
Movimiento/fisiología , Caminata/fisiología , Aeronaves , Simulación por Computador , Aglomeración/psicología , Humanos , Modelos Lineales , Modelos Teóricos , Peatones , Conducta Social
13.
PLoS One ; 15(3): e0228599, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32130219

RESUMEN

BACKGROUND: The purpose of the study was to determine the impact of the performance of bimanual coordination tasks with specific characteristics on the changes in quality of coordination, musculoskeletal load of the upper limbs and cognitive functions. METHODS AND FINDINGS: A group of 26 people aged 60-67 years performed 6 sessions of bimanual coordination training. Each session included set of tasks that varied depending on the shape in which the cursor moved, the coordination mode (in-phase, anti-phase, complex) and the tracking mode (imposed or freely chosen speed). Performance was assessed by: Error, Variability and Execution. The load of upper limb muscles was expressed with the value of the normalized EMG amplitude. Cognitive functions were evaluated using the Vienna Test System. The Variability and Error values obtained during the sixth training session decreased by more than 50% of the initial values. Tasks with freely chosen speed showed changes from 15% to 34% for Error and from 45% to 50% for Variability. For tasks with imposed speed and coordination mode anti-phase or complex it was between 51% and 58% for Error and between 58% and 68% for Variability. Statistically significant differences between load during the sixth training session compared to the first session occurred in three out of four muscles and were between 9% to 39%. There were statistically significant differences in motor time and no differences in variables describing attention and working memory. CONCLUSIONS: Coordination mode is meaningful for improving coordination skills; tasks in the anti-phase and complex are recommended. Tracking mode also plays a role, tasks with an imposed cursor movement speed have greater potential to improve coordination skills than tasks with freely chosen. Improved control skills resulted in the reduction of upper limb musculoskeletal load. It can be assumed that an increase in coordination skills with the use of appropriate training can help to reduce musculoskeletal load.


Asunto(s)
Envejecimiento/fisiología , Ataxia/rehabilitación , Cognición/fisiología , Lateralidad Funcional/fisiología , Destreza Motora/fisiología , Desempeño Psicomotor/fisiología , Anciano , Envejecimiento/psicología , Ataxia/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Músculo Esquelético/fisiología , Resultado del Tratamiento , Extremidad Superior
14.
PLoS One ; 15(3): e0230521, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32191742

RESUMEN

Spatio-temporal variation in resource availability leads to a variety of animal movement strategies. In the case of ungulates, temporally unpredictable landscapes are associated with nomadism, while high predictability in the resource distribution favours migratory or sedentary behaviours depending on the spatial and temporal scale of landscape dynamics. As most of the surveys on moose (Alces alces) movement behaviours in Europe have been conducted on Scandinavian populations, little is known about the movement strategies of moose at the southern edge of the species' range. We expected that decreasing habitat patchiness in central Europe would be associated with the prevalence of migratory behaviours. To verify this hypothesis, we analysed 32 moose fitted with GPS collars from two study areas in eastern Poland which differed in a level of habitat patchiness. We classified moose movements using the net squared displacement method. As presumed, lower patchiness in the Biebrza study site was associated with the predominance of individuals migrating short-distance, while in more patchy landscape of Polesie, resident moose dominated. At the individual level, the propensity of moose to migrate decreased with increasing abundance of forest habitats in their summer ranges. In addition, the parameters (migration distance, timing and duration) for migratory individuals varied substantially between individuals and years. Yet, in spring individual moose expressed a consistent migration timing across years. There was little synchronization of migration timing between individuals from the same population both in spring and autumn, which may have been related to mild weather conditions. We observed that moose postponed their migrations and started movement toward summer ranges at a similar time window in years when spring was delayed due to harsh weather. Hence, in light of global warming, we presume further changes in animal movements will arise.


Asunto(s)
Migración Animal/fisiología , Ciervos/fisiología , Ecosistema , Movimiento/fisiología , Animales , Europa (Continente) , Femenino , Bosques , Geografía , Masculino , Estaciones del Año , Temperatura , Factores de Tiempo
15.
PLoS One ; 15(3): e0230367, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32191757

RESUMEN

Serotonin (5-HT) is a neuromodulator secreted from serotonergic neurons located in the pons and upper brain stem in a behavioral context-dependent manner. The serotonergic axon terminals innervate almost the whole brain, causing modulatory actions on various brain functions including vision. Our previous study demonstrated the visual responses of neurons in the primary visual cortex (V1) of anesthetized monkeys were modulated by the activation of 5-HT receptors depending on the response magnitude, in which 5-HT2A receptor-selective agonists enhanced weak visual responses but not strong responses. This observation suggests that the activation of serotonergic receptors modulates neuronal visual information processing to improve the behavioral detectability of a stimulus. However, it remains unknown if 5-HT improves visual detectability at the behavioral level. To investigate this point, visual detectability was measured as contrast sensitivity (CS) in freely moving rats using a two-alternative forced-choice visual detection task (2AFC-VDT) combined with the staircase method. The grating contrast was decreased or increased step by step after a correct choice (hit) or incorrect choice (miss), respectively. CS was evaluated as an inverse value of the visual contrast threshold. The effect of the intraperitoneal administration of fluoxetine (FLX, 5 mg/kg), a selective serotonin reuptake inhibitor, on CS was tested. The CS of rats was significantly higher in FLX than control conditions, and the drug effect showed specificity for the spatial frequency (SF) of a grating stimulus, in which CS improvement was observed at optimal SF but not non-optimal high SF. Thus, we conclude that endogenously-secreted serotonin in the brain improves visual detectability, which may be mediated by vision-related neurons acquiring SF information of the visual stimulus.


Asunto(s)
Conducta Animal/efectos de los fármacos , Sensibilidad de Contraste/efectos de los fármacos , Movimiento/fisiología , Serotonina/farmacología , Animales , Ingestión de Líquidos , Masculino , Ratas Long-Evans
16.
Phys Ther ; 100(3): 554-563, 2020 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-32043130

RESUMEN

Bones are the third most common site for cancer metastases, and the axial skeleton is the most frequent skeletal location. In a postmortem study, bone metastases were reported in 70% of breast and prostate cancer patients. Bone metastases from breast, lung, prostate, thyroid, and kidney cancers account for 80% of all bone metastases. Bone lesions exist in 60% of newly diagnosed multiple myeloma patients. With increasing numbers of people who have survived cancer, many patients with cancer and axial skeletal bony metastases will be seen by physical and occupational therapists. Guidelines are lacking on how to perform physical examinations and provide exercise programs for these patients without compromising the diseased spine. In this article, we discuss the available evidence for similar spinal conditions, the biomechanics of spinal load, and changes associated with posture and weight load. We provide recommendations on how to assess a patient's strength, how to strengthen without compromising the diseased spine, and how to teach patients to use correct body mechanics during mobility and activities of daily living.


Asunto(s)
Supervivientes de Cáncer , Compresión de la Médula Espinal/terapia , Neoplasias de la Columna Vertebral/secundario , Fracturas Espontáneas/etiología , Fracturas Espontáneas/prevención & control , Humanos , Inestabilidad de la Articulación/diagnóstico , Movimiento/fisiología , Postura/fisiología , Factores de Riesgo , Sensibilidad y Especificidad , Compresión de la Médula Espinal/complicaciones , Compresión de la Médula Espinal/diagnóstico , Fracturas de la Columna Vertebral/prevención & control , Neoplasias de la Columna Vertebral/diagnóstico por imagen , Columna Vertebral/fisiopatología , Soporte de Peso
17.
PLoS One ; 15(2): e0228726, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32023300

RESUMEN

In this study, we introduce a hierarchical and modular computational model to explain how the CNS (Central Nervous System) controls arm reaching movement (ARM) in the frontal plane and under different conditions. The proposed hierarchical organization was established at three levels: 1) motor planning, 2) command production, and 3) motor execution. Since in this work we are not discussing motion learning, no learning procedure was considered in the model. Previous models mainly assume that the motor planning level produces the desired trajectories of the joints and feeds it to the next level to be tracked. In the proposed model, the motion control is described based on a regulatory control policy, that is, the output of the motor planning level is a step function defining the initial and final desired position of the hand. For the command production level, a nonlinear predictive model was developed to explain how the time-invariant muscle synergies (MSs) are recruited. We used the same computational model to explain the arm reaching motion for a combined ARM task. The combined ARM is defined as two successive ARM such that it starts from point A and reaches to point C via point B. To develop the model, kinematic and kinetic data from six subjects were recorded and analyzed during ARM task performance. The subjects used a robotic manipulator while moving their hand in the frontal plane. The EMG data of 15 muscles were also recorded. The MSs used in the model were extracted from the recorded EMG data. The proposed model explains two aspects of the motor control system by a novel computational approach: 1) the CNS reduces the dimension of the control space using the notion of MSs and thereby, avoids immense computational loads; 2) at the level of motor planning, the CNS generates the desired position of the hand at the starting, via and the final points, and this amounts to a regulatory and non-tracking structure.


Asunto(s)
Brazo/fisiología , Sistema Nervioso Central/fisiología , Modelos Neurológicos , Movimiento/fisiología , Músculo Esquelético/fisiología , Dinámicas no Lineales , Humanos
18.
Medicine (Baltimore) ; 99(5): e18941, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32000413

RESUMEN

The abnormal inter-segmental coordination of the spine during lifting could be used to monitor disease progression and rehabilitation efficacy in patients with ankylosing spondylitis (AS). This study aimed to compare the inter-segmental coordination patterns and variability of the spine during lifting between patients with AS (n = 9) and control (n = 15) groups.Continuous relative (CRP) and deviation (DP) phases between each segment of the spine (two lumbar and three thorax segments) and lumbosacral joint were calculated. The CRP and DP curves among participants were decomposed into few functional principal components (FPC) via functional principal component analysis (FPCA). The FPC score of CRP or DP of the two groups were compared, and its relationship with the indexes of spinal mobility was investigated.Compared with the control group, the AS patients showed more anti-phase coordination patterns in each relative upper spine segment and lumbosacral joint. In addition, either less or more variation was found in the coordination of each relative lower spine segment and lumbosacral joint during different time periods of lifting for these patients. Some cases were considerably related to spinal mobility.the inter-segmental coordination of the spine was altered during lifting in AS patients to enable movement, albeit inefficient and might cause spinal mobility impairment.


Asunto(s)
Elevación , Movimiento/fisiología , Columna Vertebral/fisiopatología , Espondilitis Anquilosante/fisiopatología , Fenómenos Biomecánicos , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pelvis/fisiopatología , Rango del Movimiento Articular
19.
PLoS One ; 15(2): e0228872, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32069321

RESUMEN

This study has investigated the immediate effect of induced hindlimb length difference on hindlimb lameness measured as differences in minimum (Pmin) and maximum (Pmax) pelvic heights in 16 horses trotting in a straight line and lungeing on both hard and soft surfaces with body-mounted inertial sensors. Hindlimb length differences were induced by applying an Easyboot Glue-on shoe to one hindlimb. Changes in Pmin and Pmax with induced hindlimb length difference were assessed with a two-way repeated-measures ANOVA with trial (straight, lunge with inside limb elevation, lunge with outside limb elevation) and surface (hard, soft) as within-subject factors. Change in Pmin, indicating an impact-type lameness, in the hind limb with the elevation, was significant in both the straight line and while lunging on both hard and soft surfaces. Change in Pmax, indicating pushoff-type lameness, in the opposite, non-elevated hind limb, was significant when trotting in a straight line but not while lunging.


Asunto(s)
Miembro Posterior/patología , Enfermedades de los Caballos/diagnóstico , Cojera Animal/diagnóstico , Animales , Fenómenos Biomecánicos , Femenino , Marcha/fisiología , Análisis de la Marcha/métodos , Análisis de la Marcha/veterinaria , Miembro Posterior/fisiopatología , Enfermedades de los Caballos/patología , Enfermedades de los Caballos/fisiopatología , Caballos , Cojera Animal/patología , Cojera Animal/fisiopatología , Masculino , Movimiento/fisiología , Pelvis/fisiopatología
20.
J Sports Sci ; 38(7): 759-766, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32100628

RESUMEN

This study aimed to compare the reliability and magnitude of velocity variables between 3 variants of the bench press (BP) exercise in participants with and without BP training experience. Thirty males, 15 with and 15 without BP experience, randomly performed 3 variants of the BP on separate sessions: (I) concentric-only, (II) fast-eccentric and (III) controlled-eccentric. The mean velocity (MV) and maximum velocity (Vmax) of the concentric phase were collected against 3 loads (≈30%1RM, 50%1RM, and 75%1RM) with a linear velocity transducer. Reliability was high regardless of the variable, BP variant, and load (coefficient of variation [CV] ≤ 4.47%, intraclass correlation coefficient [ICC] ≥ 0.87). The comparison of the CVs suggested a higher reliability for the fast-eccentric BP (8 out of 12 comparisons), followed by the concentric-only BP (5 out of 12 comparisons), and finally the controlled-eccentric BP (never provided a higher reliability). No differences in reliability were observed between experienced (CV ≤ 4.71%; ICC ≥ 0.79) and non-experienced (CV ≤ 6.29%; ICC ≥ 0.76) participants. The fast-eccentric BP provided the highest MV (p < 0.05) and no differences were observed for Vmax. These results support the assessment of movement velocity during the fast-eccentric BP even in participants without experience.


Asunto(s)
Entrenamiento de Resistencia/métodos , Extremidad Superior/fisiología , Levantamiento de Peso/fisiología , Adolescente , Estudios Cruzados , Humanos , Masculino , Movimiento/fisiología , Fuerza Muscular/fisiología , Análisis y Desempeño de Tareas , Adulto Joven
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