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BACKGROUND: In daily life tasks of the upper limb, we must make quick corrections with our hands in unstable postural situations. Postural and reaching control mechanisms are involved in the accurate execution of upper-limb tasks. RESEARCH QUESTION: This research aimed to determine the effect of different postural stability conditions on the motor performance of the upper limb in a reaching task with non-static targets. METHODOLOGY: 19 young participants performed a reaching task toward targets that exhibited a change in position (at 200 or 600â¯ms) in different postural conditions (bipedal-firm, bipedal-foam, and unipedal-foam surface). Performance on the screen (motion time and spatial error), balance (center of pressure displacements, CoP), and index finger movements were recorded during the reaching task. RESULTS: The instability affects the finger kinematic (displacements) and CoP kinematic (displacements, speed, and smoothness) without affecting the performance on the screen (precision and duration). The timing of target change affects the performance on the screen, finger kinematic (speed and smoothness), and CoP kinematic (displacements, speed, and smoothness). SIGNIFICANCE: Postural and reaching control systems enable accurate hand motions in less stable situations, even in reaching tasks with non-static targets. The postural and reaching control systems can protect the end-effector performance during unstable conditions but not during trials with less time to correct the motion.
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Equilibrio Postural , Desempeño Psicomotor , Humanos , Equilibrio Postural/fisiología , Fenómenos Biomecánicos , Masculino , Femenino , Adulto Joven , Desempeño Psicomotor/fisiología , Dedos/fisiología , Adulto , Movimiento/fisiología , Extremidad Superior/fisiologíaRESUMEN
Older adults adapt the execution of complex motor tasks to use compensatory strategies in the reaching-to-grasping (i.e., prehension) movement. The presence of postural constraints may exacerbate these compensatory strategies. Therefore, we investigated the reach-to-grasp action with different postural constraints (sitting, standing, and walking) in younger and older people and evaluated the postural stability during the reach-to-grasp action. Thirty individuals (15 younger and 15 older adults) performed the prehension under three postural tasks: sitting, standing, and walking. The reaching movement was slower in the walking task than in the other two postural tasks; however, there was no difference between the age groups. For the grasping action, the older adults presented a larger grip aperture, and the peak grip aperture occurred earlier during hand transportation in sitting and standing tasks. In the standing task, the margin of stability was smaller for older adults. In the walking task, there was no difference between the groups for the margin of stability. Also, prehension during sitting and standing tasks were similar, and both differed from walking across age groups. Finally, older adults reduced their margin of stability compared to younger adults, but only in the standing task. The margin of stability was similar between age groups during the walking task. We concluded that age affected grasping (distal component) but not reaching (proximal component), suggesting that healthy older adults have more difficulty controlling distal than proximal body segments.
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Mano , Caminata , Humanos , Anciano , Movimiento , Posición de Pie , Sedestación , Equilibrio PosturalRESUMEN
AIM: To systematically review evidence of the effectiveness of sticky mittens training to improve reaching skills and manual exploration of full-term and at-risk infants and optimal training dosage. METHODS: The Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guided this systematic review. The electronic search was performed from September 2017 to August 2021 on PubMed, Scopus, Science Direct, and Cochrane databases. Eligibility criteria followed PICO terms: clinical trials investigating the effects of sticky mittens training on reaching skills and manual exploration of full-term and at-risk infants. PEDro scale and GRADE assessed methodological quality and quality of evidence, respectively. RESULTS: Eight studies (313 children) were included. Five studies found statistically significant differences between experimental and control groups (62.6%). One study presented high methodological quality. Evidence synthesis showed very low and low evidence of the beneficial effects of sticky mittens training in full-term and at-risk infants, respectively. CONCLUSIONS: Findings suggest that sticky mittens training facilitates reaching skills and manual exploration. However, results should interpretation with caution because studies targeted full-term infants. Future research should focus on infants at risk or with motor impairments since sticky mittens training seems to show positive effects and is easy to apply.
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Destreza Motora , Modalidades de Fisioterapia , Humanos , Lactante , Modalidades de Fisioterapia/instrumentaciónRESUMEN
Despite the recognized importance of bodily movements in spatial audition, few studies have integrated action-based protocols with spatial hearing in the peripersonal space. Recent work shows that tactile feedback and active exploration allow participants to improve performance in auditory distance perception tasks. However, the role of the different aspects involved in the learning phase, such as voluntary control of movement, proprioceptive cues, and the possibility of self-correcting errors, is still unclear. We study the effect of guided reaching exploration on perceptual learning of auditory distance in peripersonal space. We implemented a pretest-posttest experimental design in which blindfolded participants must reach for a sound source located in this region. They were divided into three groups that were differentiated by the intermediate training phase: Guided, an experimenter guides the participant's arm to contact the sound source; Active, the participant freely explores the space until contacting the source; and Control, without tactile feedback. The effects of exploration feedback on auditory distance perception in the peripersonal space are heterogeneous. Both the Guided and Active groups change their performance. However, participants in the Guided group tended to overestimate distances more than those in the Active group. The response error of the Guided group corresponds to a generalized calibration criterion over the entire range of reachable distances. Whereas the Active group made different adjustments for proximal and distal positions. The results suggest that guided exploration can induce changes on the boundary of the auditory reachable space. We postulate that aspects of agency such as initiation, control, and monitoring of movement, assume different degrees of involvement in both guided and active tasks, reinforcing a non-binary approach to the question of activity-passivity in perceptual learning and supporting a complex view of the phenomena involved in action-based learning.
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Harmonious voluntary movements require efficiency in their planning and execution. Throughout middle childhood structural changes in the central nervous and musculoskeletal systems influence these processes and resultant motor behavior. In this study, we evaluated the characteristics of the motor planning and executing of aiming movements directed at targets located in different positions in space in children aged 7, 9, and 11 years. We divided 43 right-handed children, into three age groups and instructed them to perform aiming movements directed at targets using a stylus on a digital tablet. The children performed the movement with their dominant upper limbs from a starting point towards targets positioned ipsilaterally or contralaterally to this dominant limb. We analyzed temporal and spatial variables of motor performance. Younger (7-year-old) children made more errors in the initial movement direction and more frequently corrected their movements during task execution when compared to 9- and 11-year-old children who did not differ from each other. All age groups were similar in movement accuracy and precision. Movements toward contralateral targets were slower and more accurate than movements toward ipsilateral targets for all groups. These results show that performing aiming movements develop with the onset of middle childhood.
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Lateralidad Funcional , Desempeño Psicomotor , Niño , Lateralidad Funcional/fisiología , Mano/fisiología , Humanos , Movimiento/fisiología , Desempeño Psicomotor/fisiología , Extremidad SuperiorRESUMEN
Background: Natural and intuitive interfaces that monitor and promote upper limb task-specific training need to be developed. This article presents the development and testing of a touch-based game system for training and assessment of unilateral (ULR) and bilateral (BLR) reaching movements. Interaction becomes intuitive and simple by introducing in-game touch and pressure onto virtual targets projected on a custom-made large touch panel. Materials and Methods: A custom-made App integrates exergames and a biomechanical model with advanced algorithms for movement analysis. It processes and manages data from a motion-tracking sensor and a large touch panel equipped with 1222 (26 × 47) piezoresistive sensors, including high-speed readout electronics and algorithms to measure touch points and contact forces during fingertip interaction. An experiment was conducted to evaluate the experience, motivation, and movements of healthy and stroke subjects when interacting with the proposed system. The panel height, dispersion of virtual targets, and required contact force were customized based on motor skills of each group of subjects. Results: Both groups of subjects showed high level of motivation and user experience when interacting with the virtual environments. Stroke subjects performed the task slower and traveled a similar path length than healthy subjects, but with shorter range of motion. The mechanical work and potential energy profiles of both groups are consistent with those achieved when reaching real objects. Conclusions: The proposed contact-based exergames are a feasible solution for performing natural and intuitive therapeutic ULR and BLR exercises. They elicit appropriate reaching movements and contact forces in healthy and stroke subjects. The spatial and temporal attributes of the proposed solution can be customized to influence the movement and energy expenditure of specific joints.
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Individuals with stroke present several impairments in the ipsilesional arm reaching movements that can limit the execution of daily living activities. These impairments depend on the side of the brain lesion. The present study aimed to compare the arm reaching movements performed in sitting and standing positions and to examine whether the effects of the adopted posture configuration depend on the side of the brain lesion. Twenty right-handed individuals with stroke (half with right hemiparesis and a half with left hemiparesis) and twenty healthy adults (half used the left arm) reached toward a target displayed on a monitor screen placed in one of three heights (i.e., upper, central, or lower targets). Participants performed the reaches in sitting and standing positions under conditions where the target location was either well-known in advance (certainty condition) or unknown until the movement onset (uncertainty condition). The values of movement onset time, movement time, and constant error were compared across conditions (posture configuration and uncertainty) and groups for each target height. Individuals with stroke were slower and spent more time to start to move than healthy participants, mainly when they reached the superior target in the upright position and under the uncertainty condition. Individuals who have suffered a right stroke were more affected by the task conditions and those who suffered a left stroke showed less accurate reaches. Overall, these results were observed regardless of the adopted posture. The current findings suggested that ipsilesional arm reaching movements are not affected by the postural configuration adopted by individuals with stroke. The central nervous system modulates the reaching movements according to the target position, adopted posture, and the uncertainty in the final target position to be reached.
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Brazo , Accidente Cerebrovascular , Adulto , Fenómenos Biomecánicos , Humanos , Movimiento , Desempeño PsicomotorRESUMEN
AIM: Reaching Performance Scale for Stroke (RPSS) evaluates the upper limb reach-to-grasp movement quality and compensatory movements. The objective of the study was to test the reliability, construct validity, and interpretability of the Brazilian-Portuguese RPSS. METHODS: Fifty-one individuals (mean age 62 ± 10.8 years), with acute-to-chronic stroke (range: 1-300 months) were video recorded while performing a reach-to-grasp task of a cone placed both close and far from the individual. Their degree of motor impairment ranged from 4 to 59 points in the Fugl-Meyer scale. RESULTS: Reaching Performance Scale for Stroke showed excellent intra- (ICC2,1 = 1.00) and interrater (ICC2,1 = 0.98-0.99) reliability, and redundant internal consistency (Cronbach's α = 0.98). The construct validity between RPSS and Fugl-Meyer scale was strong (Spearman rho = 0.88-0.89; p < 0.0001). The scale was able to discriminate individuals with mild or moderate upper limb impairment from those with severe impairment. We found ceiling and floor effects. CONCLUSIONS: Reaching Performance Scale for Stroke showed excellent reliability and redundant internal consistency. The construct validity with the Fugl-Meyer scale was strong. Reaching Performance Scale for Stroke was able to discriminate individuals with different levels of upper limb impairment.IMPLICATIONS FOR REHABILITATIONPost-stroke individuals develop compensatory strategies to perform reaching movements with the paretic upper limb.The Reaching Performance Scale for Stroke provides a quantitative and qualitative evaluation of the reach-to-grasp movement.The Reaching Performance Scale for Stroke is suitable for use with Brazilian-Portuguese speakers and has adequate reliability and validity.
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Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Anciano , Brasil , Humanos , Persona de Mediana Edad , Paresia , Reproducibilidad de los Resultados , Extremidad SuperiorRESUMEN
The aims of this systematic review were: to investigate the use of surface electromyography in the assessment of reaching in infants; to assess the usefulness of this tool to the assessment of reaching, and its parameters and limitations; to assess the methodological quality of the studies available in the literature. The search in the databases MEDLINE, SciELO, LILACS, Embase, PEDro, Cochrane, and EBSCO resulted in 5 selected studies. The studies aimed to elucidate how muscle behavior occurs in the development of reaching. The lack of standardized recommendations for the use of EMG in infants limit the reproducibility and comparison between studies. There are challenges and limitations regarding the use of electromyography in infants, which are caused by peculiarities inherent to the development of the neuromotor and musculoskeletal systems.
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Electromiografía/métodos , Fuerza de la Mano/fisiología , Músculo Esquelético/fisiología , Desempeño Psicomotor/fisiología , Humanos , Lactante , Reproducibilidad de los ResultadosRESUMEN
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique used to enhance local synaptic efficacy and modulate the electrical activity of the cortex in neurological disorders. Researchers have sought to combine this type of stimulation with well-established therapeutic modalities, such as motor training involving Xbox Kinect games, which has demonstrated promising results. Thus, this study aimed to determine whether tDCS can enhance upper limb motor training in an eight-year-old child with Down Syndrome (DS) (cognitive age: five years, based on the Wechsler Intelligence Scale for Children). The evaluations consisted of three-dimensional analysis of upper limb kinematics during a reaching task performed before, after10 session, and one month after the intervention. The intervention protocol involved 1 20-min sessions of tDCS over the primary motor cortex at an intensity of 1 mA during Xbox Kinect game training involving an upper limb motor task. The analysis of the kinematic data revealed that in the pre-intervention evaluation, the dominant limb executed the task slowly and over a long path. These aspects improved at the post-intervention and follow-up evaluations, as demonstrated by the shorter total movement duration (3.05 vs. 1.58 vs. 1.52 s, respectively). Similar changes occurred with the non-dominant upper limb; a significant increase in movement velocity at the post-intervention and follow-up evaluations was observed (0.53 vs. 0.54 vs. 0.85 m/s, respectively). The present case report offers preliminary data from a protocol study, and the results confirm the notion that anodal tDCS combined with upper limb motor training leads to improvements in different kinematic variables.
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INTRODUCTION: Upper limb movements are affected frequently by brain ischemia (BI). Mechanisms involved in recovery and compensatory movements have developed several studies. However, less attention is given to skeletal muscles, where neuromuscular junction (NMJ) has an important role on muscle tropism and functional performance. METHODS: Animals were divided into two groups: control (C) and BI. Then, animals were skilled to perform single-pellet retrieval task, following these procedures: habituation, shaping, and single-pellet retrieval task. BI was induced using stereotaxic surgery in order to apply endothelin-1 in motor cortex, representative of movements of dominant paw. Reaching task performance was evaluated by single-pellet retrieval task 1 day before BI induction, 4 and 15 days after BI induction. After that, biceps, triceps, fingers flexor, and extensor muscles were extracted. NMJ was assessed in morphometric characteristics (total area, total perimeter, and feret). Muscle fiber cross-sectional area and connective tissue percentage were also evaluated for characterization. Student's t test was used for comparisons between C and BI groups. Tau Kendall's correlation was applied among variables from BI group. RESULTS: An increase in all NMJ morphometric parameters, as well as increase of atrophy and fibrosis in BI group compared with C. There was a high level of direct correlation between mean values of NMJ morphometry with percentage of success in reaching task in BI group. CONCLUSION: Brain ischemia-induced NMJ compensatory expansion, muscle atrophy, and fibrosis in forelimb muscles that are related to reaching performance.
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Adaptación Fisiológica/fisiología , Isquemia Encefálica/fisiopatología , Corteza Cerebral/fisiopatología , Miembro Anterior/fisiopatología , Actividad Motora/fisiología , Unión Neuromuscular/fisiopatología , Recuperación de la Función/fisiología , Animales , Masculino , Movimiento/fisiología , Desempeño Psicomotor/fisiología , RatasRESUMEN
Upper limb performance is affected by diabetes mellitus (DM). Neuromuscular junction (NMJ) is a key structure to understand the relationship between performance and morphology in DM. The aim of the study was to analyze NMJ plasticity due to DM in an animal model and its relationship with the function of forelimbs in rats. Twelve Wistar rats were divided into control (C) and DM groups. Animals were trained to perform a grasping task, following procedures of habituation, shaping, and reaching task. DM was induced using streptozotocin. Forelimb neuromuscular performance for dexterity was evaluated one day before DM induction and five weeks following induction. After that, biceps, triceps, and finger flexors and extensors were removed. Connective tissue and muscle fiber cross-sectional area (CSA) were measured. NMJ was assessed by its morphometric characteristics (area, perimeter, and maximum diameter), using ImageJ software. Motor performance analyses were made using single pellet retrieval task performance test. Student's t-test was used for comparisons between groups. A significant decrease in all NMJ morphometric parameters was observed in the DM group compared with the C group. Results showed that DM generated NMJ retraction in muscles involved in a reaching task. These alterations are related to signs of muscular atrophy and to poor reaching task performance. In conclusion, induced DM caused NMJ retraction and muscular atrophy in muscles involved in reaching task performance. Induced DM caused significantly lower motor performance, especially in the final moments of evaluation, when DM compromised the tropism of the muscular tissue.
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Animales , Masculino , Conejos , Ratas , Análisis y Desempeño de Tareas , Adaptación Fisiológica/fisiología , Diabetes Mellitus Experimental/patología , Unión Neuromuscular/patología , Ratas Wistar , Diabetes Mellitus Experimental/fisiopatología , Unión Neuromuscular/fisiopatologíaRESUMEN
BACKGROUND: Children with cerebral palsy perform small displacements during the anterior reach movement from standing position without loss of balance. There are two possible reasons for their decreased performance: the difficulty to stabilize their lower limbs during forward body inclination to reach greater distances or to control the movement of forward reaching. The objective of this study is to identify and compare the motor performance of children with CP and typically developing children, during anterior reach. METHODS: This is a cross-sectional study, composed of 28 children, 14 with spastic cerebral palsy and 14 typical children, who were all evaluated by the Pediatric Reach Test and three-dimensional motion analysis. FINDINGS: The decreased performance was shown by the lower movement control by children with cerebral palsy. The bilateral and unilateral cerebral palsy children showed lower range of motion of shoulder and trunk than typical children. INTERPRETATION: Children with cerebral palsy show lower anterior displacement and movement control and difficulty bending the trunk and flexing shoulders while reaching forward, suggesting poor postural balance.
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Parálisis Cerebral/fisiopatología , Destreza Motora , Equilibrio Postural , Rango del Movimiento Articular , Adolescente , Antropometría , Fenómenos Biomecánicos , Niño , Estudios Transversales , Femenino , Humanos , Imagenología Tridimensional , Masculino , Movimiento , Espasmo , TorsoRESUMEN
The reaching of objects is usually practiced by CP children in conventional or Virtual Reality-based therapies to enhance motor skill performance. Recently, Kinesio Taping® method has been studied to increase mechanical stability and improve functional movement of the upper limb; however, its influence on CP children´s upper limb motion has been rarely quantified due to lack of sensory measurement. Therefore, in this paper, we evaluate the biomechanical and functional effects of applying shoulder Kinesio Taping® on CP children in the reaching-transporting of virtual objects, by using a low-cost tracking device, exact robust differentiation of data and a simple nonlinear biomechanical dynamic model of the trunk and arm.
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Cinta Atlética , Parálisis Cerebral/fisiopatología , Hombro/fisiopatología , Realidad Virtual , Adolescente , Fenómenos Biomecánicos , Niño , Femenino , Humanos , Masculino , Movimiento , Rango del Movimiento Articular , Procesamiento de Señales Asistido por Computador , Extremidad Superior/fisiopatologíaRESUMEN
Stroke individuals frequently have balance problems and impaired arm movements that affect their daily activities. We investigated the influence of target uncertainty and the side of the brain lesion on the performance of arm movements and postural adjustments during reaching in a standing position by stroke individuals. Participants stood on force plates and reached a target displayed on the center of a monitor screen under conditions differentiated by the prior knowledge of the target location at the beginning of the movement. Individuals who had a stroke in the right side of the brain performed the tasks with the ipsilesional, right upper limb while the individuals with a left stroke performed with the ipsilesional, left upper limb. Healthy individuals performed with right and left limbs, which data were later averaged for statistical analysis. Kinematic analysis of the arm and lower limb joints and displacements of the center of pressure of each lower limb were compared between target conditions and groups. Stroke individuals showed larger center of pressure displacements of the contralesional compared to the ipsilesional limb while these displacements were symmetrical between lower limbs for the healthy individuals, regardless of the target condition. The target uncertainty affected both the characteristics of the arm movements and postural adjustments before movement onset. Right stroke individuals used more ankle joint movements under the uncertain compared to the certain condition. The uncertainty in target location affects the arm reaching in upright standing, but the effects depend on the side of the brain lesion.
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Brazo/fisiología , Accidente Cerebrovascular/fisiopatología , Articulación del Tobillo/fisiología , Fenómenos Biomecánicos/fisiología , Femenino , Lateralidad Funcional/fisiología , Humanos , Pierna/fisiología , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Equilibrio Postural/fisiología , Presión , Posición de Pie , IncertidumbreRESUMEN
Resumo Objetivo: Investigar o efeito do peso adicional nos ajustes proximais e distais do alcance em lactentes a termo (AT) e pré-termo tardios (PTT). Método: Foram avaliados 10 lactentes AT e 9 PTT dos 5 aos 7 meses de idade. As variáveis analisadas foram: a) ajustes proximais: unimanuais ou bimanuais; b) ajustes distais: abertura das mãos (aberta, fechada ou semiaberta) e orientação das mãos (horizontalizada, verticalizada ou oblíqua). Os procedimentos analisados foram: P1 (linha de base) e P2 (acréscimo de 20% da massa do membro superior de peso adicional). Para verificar a associação entre os procedimentos e as variáveis dependentes utilizou-se o Teste Qui-quadrado (p<0,05). Resultados: O peso adicional proporcionou a diminuição de alcances bimanuais aos 5 e 7 meses no grupo PTT, o aumento da frequência de mão verticalizada e a diminuição da frequência de mão aberta no início do movimento, aos 6 meses. No grupo AT, o peso implicou no aumento da mão verticalizada no início e no fim do movimento, aos 5 meses, e ao final do movimento, aos 7 meses, e diminuiu a frequência de mão aberta no início e final do alcance, aos 6 meses. Conclusão: O peso adicional favoreceu um movimento mais maduro na maioria das variáveis analisadas e, de forma mais expressiva, no grupo prematuro. Assim, pode tornar-se um instrumento para o treino inicial do alcance, quando o objetivo for a estimulação de alcances unimanuais com a mão verticalizada.
Abstract Objective: The aim of this work is to investigate the effects of additional weight in the proximal and distal adjustments of the reaching behavior of full-term and preterm infants. Method: We evaluated 10 full-term and 9 low risk preterm infants from 5 to 7 months age. The following variables were analyzed: a) proximal adjustments: unimanual or bimanual; b) distal adjustments: hand opening (open, closed, semi-open) and hand orientation (horizontal, vertical, oblique). Variables were analyzed in two procedures: P1 (baseline) and P2 (addition of 20% of the total mass of the infant's upper limb). To verify the association between procedures and dependent variables was applied Chi-Square Test (p<0,05). Results: Additional weight decreased of bimanual frequency for the preterm group at 5 and 7 months old, increased vertical hand frequency and decreased open hand frequency at 6 months. In the full-term group, additional weight increased the vertical hand frequency at the initiation and at the end of the movement at 5 months and at the end of the movement at 7 months. It also decreased open hand frequency at the initiation and at the end of the reaching at 6 months. Conclusion: Additional weight favored a more mature movement in the majority of variables analyzed, more expressively in the preterm group. Therefore, it can become an instrument of training this skill in the beginning of the reaching, when looking for verticalized hand unimanual reaching stimulation.
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In order to acquire reaching and independent sitting, refinement of trunk control is needed by gradually and progressively incorporating the head, thoracic, lumbar, and sacral segments. Previous studies have evaluated trunk control in a segmental way, standardizing the level of manual support in the infants' trunk during reaching. The aim of this study was to identify the level of trunk control and to analyze the influence of the difference sitting positions in late preterm and full-term infants between 6 and 8 months of age during reaching. Therefore, 36 infants born full term (control group)-FTG and 20 late preterm infants at a corrected age (experimental group)-PTG were evaluated. Most of the infants started the study at 6 months and they were evaluated monthly until 8 months of age (longitudinal study) in a total of 1-3 visits. The Segmental Assessment of Trunk Control was used to identify the level of trunk control in a segmental way, as well as to verify the capacity of the infant to maintain or regain the vertical position while sitting. Kinematic analysis was used for reaching. The infants were in a ring sitting position and at 90° of flexion. To elicit reaching, an attractive object was presented at the infant's midline and at 45° to the right and left. We found that PTG infants presented lower trunk control scores, i.e., worse control. For both groups, the ring sitting position and at 90° of flexion did not influence most kinematic variables during reaching because accurate manual support was provided for the infants' trunk. The PTG group presented less trunk displacement when at 90° of flexion. Compared to the FTG, even with accurate trunk support, the PTG group presented more immature reaches. These results suggest that accurate manual trunk support favored more stability of the trunk during the reach. Thus, early intervention is suggested for PTG infants and reaching in this age group should be trained in the ring sitting position with their trunk accurately manually supported. SATCo is an effective tool for segmental trunk evaluation.
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We examined the effect of acute and chronic sprint interval training (SIT), with or without prior caffeine intake, on levels of exercise-induced inflammatory plasma cytokines [interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α]. Twenty physically-active men ingested either a placebo (n = 10) or caffeine (n = 10) 1 h before each SIT session(13-s × 30-s sprint/15 s of rest) during six training sessions (2 weeks). The early (before, immediately after, and 45 min after the exercise) and late (24 and 48 h after the exercise) cytokine and creatine kinase (CK) responses were analyzed for the first and last training sessions. Plasma IL-6 and IL-10 peaked 45 min after the exercise, and then returned to basal values within 24 h (p < 0.05) in both groups on both occasions (p > 0.05). On both occasions, and for both groups, plasma TNF-α increased from rest to immediately after the exercise and then decreased at 45 min before reaching values at or below basal levels 48 h after the exercise (p < 0.05). Serum CK increased from rest to 24 and 48 h post-exercise in the first training session (p < 0.05), but did not alter in the last training session for the PLA group (p > 0.05). Serum CK was unchanged in both the first and last training sessions for the CAF group (p > 0.05). Two weeks of SIT induced a late decrease in the IL-6/IL-10 ratio (p < 0.05) regardless of caffeine intake, suggesting an improved overall inflammatory status after training. In conclusion, a single session of SIT induces muscle damage that seems to be mitigated by caffeine intake. Two weeks of SIT improves the late SIT-induced muscle damage and inflammatory status, which seems to be independent of caffeine intake.
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The present study aimed to investigate the influence of target height on the symmetry and amplitude of the postural adjustments assessed by the displacements of the center of pressure (COP) before and during the unilateral, arm movements in the upright position. Thirteen young, right-handed adults stood with each foot on one force platform and reached a target placed at one of three heights displayed on a monitor screen. The performance of the right arm movements (movement time and radial error), amplitude of the COP displacements of each lower limb and the percentage of body weight loading on the right lower limb before and during the reaching movements were compared across target heights conditions. Postural adjustments were symmetrical prior but asymmetrical after movement onset. Effect of target height was observed on the postural adjustments before and during the movements (i.e., amplitudes of the COP displacements increased for the higher target), mainly for the right limb. The arm performance was similar across target heights. The findings of the present study suggested that postural adjustments are dependent on the target heights to ensure success in the arm movements.
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Movimiento/fisiología , Músculo Esquelético/fisiología , Postura/fisiología , Desempeño Psicomotor/fisiología , Adaptación Fisiológica/fisiología , Adulto , Brazo/fisiología , Fenómenos Biomecánicos/fisiología , Femenino , Humanos , Masculino , Equilibrio Postural/fisiología , Tiempo de ReacciónRESUMEN
Abstract Introduction Moving the arm towards an object is a complex task. Movements of the arm joints must be well coordinated in order to obtain a smooth and accurate hand trajectory. Most studies regarding reaching movements address young subjects. Coordination differences in the neural mechanism underlying motor control throughout the life stages is yet unknown. The understanding of these changes can lead to a better comprehension of neuromotor pathologies and therefore to more suitable therapies. Methods Our purpose was to investigate interjoint coordination in three different aging groups (children, young, elderly). Kinematics and kinetics specific variables were analyzed focusing on defined parameters to get insight into arm coordination. Intersegmental dynamics was used to calculate shoulder and elbow torques assuming a 2-link segment model of the upper extremity (upper arm and forearm) with two friction-less joints (shoulder and elbow). A virtual reality environment was used to examine multidirectional planar reaching in three different directions (randomly presented). Results Seven measures were computed to investigate group interlimb differences: shoulder and elbow muscle torques (peak and impulse), work performed by shoulder and elbow joints, maximum velocity, movement distance, distance error at final position, movement duration and acceleration duration. Our data analysis showed differences between movement performances for all analyzed variables, at all ages. Conclusion We found that the intersegmental dynamics for the interlimb (left/right) comparisons were similar for the elderly and children groups as compared to the young. In addition, the coordination and control of motor tasks changes during life, becoming less effective in old age.