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1.
Nat Commun ; 12(1): 2692, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976216

RESUMO

Rapid developments of robotics and virtual reality technology are raising the requirements of more advanced human-machine interfaces for achieving efficient parallel control. Exoskeleton as an assistive wearable device, usually requires a huge cost and complex data processing to track the multi-dimensional human motions. Alternatively, we propose a triboelectric bi-directional sensor as a universal and cost-effective solution to a customized exoskeleton for monitoring all of the movable joints of the human upper limbs with low power consumption. The corresponding movements, including two DOF rotations of the shoulder, twisting of the wrist, and the bending motions, are detected and utilized for controlling the virtual character and the robotic arm in real-time. Owing to the structural consistency between the exoskeleton and the human body, further kinetic analysis offers additional physical parameters without introducing other types of sensors. This exoskeleton sensory system shows a great potential of being an economic and advanced human-machine interface for supporting the manipulation in both real and virtual worlds, including robotic automation, healthcare, and training applications.


Assuntos
Desenho de Equipamento/instrumentação , Exoesqueleto Energizado , Aparelhos Ortopédicos , Amplitude de Movimento Articular/fisiologia , Robótica/instrumentação , Extremidade Superior/fisiologia , Simulação por Computador , Desenho de Equipamento/economia , Desenho de Equipamento/métodos , Humanos , Articulações/fisiologia , Movimento/fisiologia , Robótica/economia , Robótica/métodos
2.
Comput Methods Biomech Biomed Engin ; 24(2): 137-150, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33945354

RESUMO

Estimation of muscle forces in over-actuated musculoskeletal models involves optimal distributions of net joint moments among muscles by a standard load-sharing scheme (SLS). Given that co-contractions of antagonistic muscles are counterproductive in the net joints moments, SLS might underestimate the co-contractions. Muscle co-contractions play crucial roles in stability of the glenohumeral (GH) joint. The aim of this study was to improve estimations of muscle co-contractions by incorporating electromyography (EMG) data into an upper limb musculoskeletal model. To this end, the model SLS was modified to develop an EMG-assisted load-sharing scheme (EALS). EMG of fifteen muscles were measured during arm flexion and abduction on a healthy subject and fed into the model. EALS was compared to SLS in terms of muscle forces, GH joint reaction force, and a stability ratio defined to quantify the GH joint stability. The results confirmed that EALS estimated higher muscle co-contractions compared to the SLS (e.g., above 50 N higher forces for both triceps long and biceps long during arm flexion).


Assuntos
Eletromiografia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Extremidade Superior/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Modelos Biológicos , Amplitude de Movimento Articular , Articulação do Ombro/fisiologia , Suporte de Carga
3.
PLoS One ; 16(1): e0245049, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33411819

RESUMO

Most research on power assist suits (PASs) that concerned PAS-human interactions has used human physical reactions as criteria to evaluate the mechanical function, however, with minimal emphasis on human reactions in response to PASs. In this study, we focused on the physiological responses of the upper limbs including muscle activity of the biceps brachii and the triceps brachii, co-activation, force steadiness (CV) and rated perceived exertion (RPE) to various patterns of bilateral assistive force, such as unilateral assistance (L0% & R67% [% = percentage of workload force, L = left arm, R = right arm], L67% & R0%, L0% & R33%, L33% & R0%), symmetrical (L0% & R0%, L33% & R33%, L67% & R67%) and asymmetrical bilateral assistance (L33% & R67%, L67% & R33%), during bilateral isometric force-matching tasks. The results showed a similar muscular response of the two arms to bilateral assistive conditions, and the muscle activity of the arm that was being observed decreased only when the assistive force that applied on itself increased, indicating that both arms may have adopted similar but independent motor control mechanisms to acclimate to the bilateral assistive forces. Comparison between the two unilateral assistances (L0% & R33% and L33% & R0%) and the two asymmetrical bilateral assistances (L33% & R67%, L67% & R33%) showed no significant differences in muscular responses, CV and RPE, indicating that bilateral assistances with bilateral interchanged assistive levels may be equally effective regardless of which arm the higher assistive force is applied to. Comparison between unilateral and symmetrical assistive conditions that have similar overall workloads (L67% & R0%, L33% & R33%, L0% & R67%) showed a lower CV and RPE score at symmetrical assistance compared with unilateral assistance, suggesting that assisting both arms with the same level simultaneously improves task performances compared with applying the assistive force to only one arm.


Assuntos
Contração Isométrica/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Equipamentos de Autoajuda , Extremidade Superior/fisiologia , Adulto , Eletromiografia , Humanos , Masculino , Músculo Esquelético/fisiologia
4.
J Sports Med Phys Fitness ; 61(5): 656-665, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33480511

RESUMO

BACKGROUND: The aim of this study was to examine the fitness profile of the Italian national male Team-Handball players of different competitive level. METHODS: Forty-one male handball players from the senior (N.=21, height 1.90±0.06m, body mass 94.04±11.59kg, BMI 26.13±2.45) to the junior category (N.=20, height 1.86±0.06m, body weight 84.99±12.52kg, BMI: 24.56±3.35) Italian National Teams participated in this study. Players were tested for lower and upper limbs muscle strength, change of direction ability and specific endurance. Lower limbs explosive strength was assessed with squat (SJ) countermovement (CMJ), stiff leg (stiffness) jumps. Explosive strength was assessed by measuring kinematic aspects of squat and bench exercises. Change of direction ability was assessed with the 505 test. The Yo-Yo intermittent recovery test (YYIR1) was considered for specific endurance. RESULTS: Large and significant differences (d>1; partial η2>0.14; P<0.01) between senior and junior national team players were found in anthropometrics, jumping, power, sprint, agility, and aerobic fitness (junior body weight accounting for 10% less than the senior one, P=0.021; SJ and CMJ in juniors smaller than the seniors by 15% and 12%, P=0.000 and P=0.001, respectively). Similar differences were found among positional roles (goalkeepers, backs, centers, pivots, wings), suggesting practical implications for training. CONCLUSIONS: The differences between the competitive level and the playing role in relevant handball performance were reported in Italian national team players. The magnitude of the differences suggests the need of individual training approach when dealing with the young handball players.


Assuntos
Desempenho Atlético/fisiologia , Comportamento Competitivo/fisiologia , Aptidão Física , Esportes/fisiologia , Estatura , Índice de Massa Corporal , Teste de Esforço , Humanos , Itália , Extremidade Inferior/fisiologia , Masculino , Destreza Motora/fisiologia , Força Muscular , Condicionamento Físico Humano , Extremidade Superior/fisiologia , Adulto Jovem
5.
J Neurosci ; 41(7): 1443-1454, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33334866

RESUMO

Renshaw cells mediate recurrent inhibition between motoneurons within the spinal cord. The function of this circuit is not clear; we previously suggested based on computational modeling that it may cancel oscillations in muscle activity around 10 Hz, thereby reducing physiological tremor. Such tremor is especially problematic for dexterous hand movements, yet knowledge of recurrent inhibitory function is sparse for the control of the primate upper limb, where no direct measurements have been made to date. In this study, we made intracellular penetrations into 89 motoneurons in the cervical enlargement of four terminally anesthetized female macaque monkeys, and recorded recurrent IPSPs in response to antidromic stimulation of motor axons. Recurrent inhibition was strongest to motoneurons innervating shoulder muscles and elbow extensors, weak to wrist and digit extensors, and almost absent to the intrinsic muscles of the hand. Recurrent inhibitory connections often spanned joints, for example from motoneurons innervating wrist and digit muscles to those controlling the shoulder and elbow. Wrist and digit flexor motoneurons sometimes inhibited the corresponding extensors, and vice versa. This complex connectivity presumably reflects the flexible usage of the primate upper limb. Using trains of stimuli to motor nerves timed as a Poisson process and coherence analysis, we also examined the temporal properties of recurrent inhibition. The recurrent feedback loop effectively carried frequencies up to 100 Hz, with a coherence peak around 20 Hz. The coherence phase validated predictions from our previous computational model, supporting the idea that recurrent inhibition may function to reduce tremor.SIGNIFICANCE STATEMENT We present the first direct measurements of recurrent inhibition in primate upper limb motoneurons, revealing that it is more flexibly organized than previous observations in cat. Recurrent inhibitory connections were relatively common between motoneurons controlling muscles that act at different joints, and between flexors and extensors. As in the cat, connections were minimal for motoneurons innervating the most distal intrinsic hand muscles. Empirical data are consistent with previous modeling: temporal properties of the recurrent inhibitory feedback loop are compatible with a role in reducing physiological tremor by suppressing oscillations around 10 Hz.


Assuntos
Inibição Neural/fisiologia , Extremidade Superior/fisiologia , Animais , Axônios/fisiologia , Estimulação Elétrica , Potenciais Pós-Sinápticos Excitadores/fisiologia , Retroalimentação Fisiológica , Feminino , Macaca mulatta , Neurônios Motores/fisiologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Neurônios/fisiologia , Células de Renshaw/fisiologia , Medula Espinal/citologia , Medula Espinal/fisiologia , Extremidade Superior/inervação
6.
Sports Health ; 13(1): 37-44, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32903164

RESUMO

CONTEXT: Plyometric training has been shown to be beneficial in adolescent overhead athletes. However, existing research on the effects of plyometrics on sport performance has been limited. OBJECTIVE: To systematically review the current literature to investigate whether plyometric training intervention improves upper- and lower-body sport performance. DATA SOURCES: Two electronic databases (MEDLINE and Web of Science) were searched using specific Medical Subject Headings (MeSH) terms up to February 2019, and hand-searching was performed by looking to relevant studies that were cited in other studies. STUDY SELECTION: A total of 932 items were identified and were further assessed for the eligibility in the systematic review. For a study to be eligible, each of the following inclusion criteria had to be met: (1) participants were aged 13 to 18 years and selected from a sports or athletic population and the study (2) involved the evaluation of a plyometric training intervention with an aim to improve sports performance; (3) must have included a control intervention and/or control group; (4) included a quantitative objective measure of sport performance variables concerning throwing, jumping, running, and sprinting; and (5) was published in English. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 3. DATA EXTRACTION: A first screening was conducted based on title and abstract of the articles. In the second screening, the full text of the remaining articles was evaluated for the fulfillment of the inclusion criteria. RESULTS: A total of 14 studies were included in this review. The methodological quality of the included studies ranged from low to moderate. There is moderate evidence that plyometric training intervention improves throwing and jumping performances. There is also preliminary evidence that plyometric training intervention improves sprint performance. CONCLUSION: The current evidence suggests that sport performance consisting of throwing capacity, jumping ability, and sprint performance significantly improved due to plyometric training interventions in adolescent overhead athletes.


Assuntos
Desempenho Atlético/fisiologia , Exercício Pliométrico , Esportes Juvenis/fisiologia , Adolescente , Humanos , Extremidade Inferior/fisiologia , Corrida/fisiologia , Extremidade Superior/fisiologia
7.
Sports Health ; 13(3): 278-284, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33320785

RESUMO

BACKGROUND: Pain is a characteristic, unpleasant sensory and emotional experience associated with actual or potential tissue damage. Pain is a subjective sensation, modulated by many factors such as age, sex, emotional state, national origin, or physical activity. Moreover, it is closely associated with intense physical activity, injuries, and traumas, which can significantly modulate pain tolerance. HYPOTHESIS: We postulate that there are correlations between past injuries, physical activity, and intensity of pain perception (pain threshold and pain tolerance) in a population of healthy men and women. STUDY DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: Level 4. METHODS: A total of 302 participants aged 18 to 32 years were included. The participants were divided into 2 groups (active and inactive individuals), in accordance with the scope of physical activity they had indicated. The test of pressure pain threshold and pressure pain tolerance was performed using an algometer. RESULTS: Active women achieved significantly higher pain threshold and pain tolerance values in all measurements on the upper limb (except for the pain threshold on the left hand) compared with inactive women. In mediation analysis, the effect of injury remained significant only for the pressure pain tolerance in the dominant arm and the left hand in the female group. In the case of men, there were no significant differences in all measurements in view of the threshold and tolerance for pain between the groups of active and inactive and between men with injuries and without injuries. CONCLUSION: Intense, regular physical activity is a factor modulating the perception of pain. This was demonstrated as lowered sensitivity to pain stimuli in a population of healthy women. CLINICAL RELEVANCE: Injuries should be treated as an important factor modulating the perception of pain. We recommend detailed monitoring of injuries during treatment and control of pain sensation.


Assuntos
Traumatismos em Atletas/psicologia , Percepção da Dor/fisiologia , Adolescente , Adulto , Exercício Físico/psicologia , Feminino , Humanos , Masculino , Limiar da Dor , Estudos Retrospectivos , Fatores Sexuais , Extremidade Superior/fisiologia , Adulto Jovem
8.
PLoS One ; 15(12): e0244321, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33338075

RESUMO

BACKGROUND: Women involved in repetitive, fatiguing, jobs develop more neck and/or shoulder musculoskeletal disorders than men. Sex differences in the pain response to exercise could contribute to the higher prevalence of neck/shoulder musculoskeletal disorders in women. The objective of this study was to assess sex differences in pain sensitivity following a fatiguing upper limb task. Relationships between measures of fatigue and of the sensitivity to nociceptive and to non-nociceptive stimulations were also explored. METHODS: Thirty healthy adults (15 women) performed a fatiguing repetitive pointing task with their dominant arm. Upper limb electromyography was recorded from the dominant upper trapezius, anterior deltoid and bicep brachii and from the contralateral tibialis anterior. Before and immediately after the repetitive pointing task, pressure pain and light touch sensitivity thresholds were measured over the same muscles. RESULTS: Electromyographic signs of fatigue were observed only in the anterior deltoid and biceps brachii muscles. Pressure pain thresholds over both muscles increased slightly (effect size ≤ 0.34), but no changes occurred over the upper trapezius and the tibialis anterior. Light touch thresholds increased moderately to importantly after the repetitive pointing task over all four muscles (effect sizes = 0.58 to 0.87). No sex differences were observed in any sensory variable. Moreover, no or weak correlations (r = -0.27 to 0.39) were observed between electromyographical signs of fatigue, light touch threshold and pressure pain threshold variables. CONCLUSIONS: We observed sex-independent effects of a repetitive upper limb task on the sensitivity to painful and to nonpainful stimuli. Moreover, the hypoalgesia induced by the repetitive pointing task was weak and localized, and did not directly correlate with the induced muscle fatigue. Results suggest that fatigue-related changes in the sensitivity to noxious and innocuous stimuli could not explain women's greater prevalence of neck/shoulder musculoskeletal disorders.


Assuntos
Transtornos Traumáticos Cumulativos/fisiopatologia , Percepção da Dor/fisiologia , Limiar da Dor/fisiologia , Adulto , Braço/fisiologia , Transtornos Traumáticos Cumulativos/metabolismo , Eletromiografia/métodos , Fadiga/fisiopatologia , Feminino , Humanos , Masculino , Movimento/fisiologia , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Pescoço/fisiologia , Caracteres Sexuais , Fatores Sexuais , Ombro/fisiologia , Tato/fisiologia , Extremidade Superior/fisiologia
9.
Rev. cuba. invest. bioméd ; 39(4): e567, oct.-dic. 2020. tab, graf
Artigo em Espanhol | LILACS, CUMED | ID: biblio-1156454

RESUMO

Introducción: El baloncesto es objeto de múltiples estudios que incluye la valoración mediante tecnologías actuales como la bioimpedancia. Objetivo: Comparar los índices de asimetría (IA) de las extremidades superiores e inferiores en jugadores de baloncesto universitario por nivel deportivo. Método: Se evaluaron 24 jugadores de baloncesto de diferente nivel competitivo, representativo 1) universitario (n = 12) y 2) facultad (n = 12). Se determinó la circunferencia de brazos y piernas, además de masa magra y grasa por bioimpedancia. Se determinó el índice de asimetría de los miembros inferiores y superiores y se compararon por nivel deportivo. Resultados: La comparación de los índices de asimetría entre brazos y piernas en el grupo total identificó diferencias estadísticamente significativas (p < 0,05) en lo referente a la masa grasa, con mayor adiposidad en extremidades superiores, y un índice de asimetría de -10,8. Cuando se compararon las mismas variables en función del nivel deportivo, los jugadores representantes de la universidad mostraron mayores valores (p < 0,05) en el índice de asimetría de la masa total, circunferencias, masa magra y masa grasa. Las comparaciones intergrupales señalan diferencias en los índices de asimetría del brazo vs. la pierna en masa magra para ambos grupos (p < 0,05) mientras que los de la facultad mostraron diferencia también para grasa con índice de asimetría de 18,3 (p < 0,05). Conclusiones: Indistintamente del nivel deportivo, existen diferentes niveles del índice de asimetría entre extremidades superiores e inferiores en el componente de masa grasa, aunque menores valores del índice de asimetría fueron característicos de los individuos de mayor nivel deportivo(AU)


Introduction: Basketball has been the object of many studies, including assessments based on current technologies such as bioimpedance. Objective: Compare the asymmetry indices (AI) for upper and lower limbs in university basketball players. Methods: An evaluation was conducted of 24 basketball players from different competitive levels, representing 1) the university (n = 12) and 2) the school (n = 12). Determination was made of arm and leg circumference, as well as lean mass and fat by bioimpedance. The lower and upper limb asymmetry index was estimated and compared between the competitive levels. Results: Comparison of the arms and legs asymmetry indices in the total group revealed statistically significant differences (p < 0.05) as to fat mass, with greater adiposity in the upper limbs and an asymmetry index of 10.8. Comparison of the same variables between the sports levels found that players representing the university displayed higher values (p < 0.05) in the asymmetry index for total mass, circumferences, lean mass and fat mass. Comparison between the groups found differences in the arm vs. leg asymmetry indices for lean mass in both groups (p < 0.05), whereas the school players also showed differences for fat, with an asymmetry index of 18.3 (p < 0.05). Conclusions: Regardless of the sports level, different asymmetry indices are found between upper and lower limbs as to fat mass, though smaller asymmetry index values were characteristic of individuals from a higher sports level(AU)


Assuntos
Humanos , Masculino , Adulto , Adulto Jovem , Basquetebol/fisiologia , Impedância Elétrica , Extremidade Inferior/fisiologia , Extremidade Superior/fisiologia , Universidades/ética
10.
Tog (A Coruña) ; 17(2): 232-237, nov. 2020. tab
Artigo em Espanhol | IBECS | ID: ibc-198821

RESUMO

OBJETIVOS: evaluar la efectividad de la combinación de la neuromodulación eléctrica espinal transcutánea asistida con exoesqueleto robótico en la recuperación de la función de la extremidad superior en personas con esclerosis múltiple. MÉTODOS: ensayo clínico aleatorizado con grupo control (doble ciego). Para la recogida de datos se emplean diversas escalas como: Nine Hole Peg Test, Functional Independence Measure o Modified Ashworth Scale entre otras. El estudio durará 18 semanas en las que se realizarán cuatro evaluaciones: inicial, continua, postratamiento y de seguimiento tras dos meses sin tratamiento. La muestra estará formada por personas diagnosticadas de esclerosis múltiple. DISCUSIÓN: se espera que la combinación de estas técnicas o abordajes mejore la funcionalidad de la extremidad superior en estas personas y consecuentemente su calidad de vida e independencia en su cotidianeidad


OBJECTIVE: Evaluate the effectiveness of combination in robotic exoskeleton-assisted transcutaneous spinal electrical neuromodulation on upper limb recovery function in people with multiple sclerosis. METHODS: Randomized clinical trial with control group (double blind). Data was collected with various scales such as: Nine Hole Peg Test, Functional Independence Measure or Modified Ashworth Scale. The study will last 18 weeks in wich 4 evaluations will be made: initial, continuous, post-treatment and follow-up after 2 months without treatment. The sample will be created on patients diagnosed multiple sclerosis. DISCUSSION: The combination of these techniques or approaches is expected to improve the functionality of upper limb on these patients and consequently their quality of life and independence in their daily life


Assuntos
Humanos , Adolescente , Adulto Jovem , Adulto , Esclerose Múltipla/reabilitação , Extremidade Superior/fisiologia , Estimulação Elétrica Nervosa Transcutânea/métodos , Robótica/métodos , Resultado do Tratamento , Exoesqueleto Energizado/tendências , Método Duplo-Cego , Esclerose Múltipla/diagnóstico , Qualidade de Vida , Estudos Longitudinais , Estudos Prospectivos
11.
Medicine (Baltimore) ; 99(42): e22837, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33080765

RESUMO

OBJECTIVES: The Thrower's Ten Exercise program is an exercise program especially designed to improve the strength, power and endurance of the shoulder complex. The aim of this study was to investigate the effects of the Thrower's Ten exercises on the upper extremity performance in healthy sedentary individuals. METHODS: 36 healthy sedentary individuals completed this study conducted with a randomized controlled design. The subjects were divided into 2 groups: exercise and control. The exercise group received a training of the Thrower's Ten exercises of 50-minute sessions 3 times a week for a duration of 8 weeks. Before and after the study, the subjects were tested for dynamic balance on the upper extremity with the Upper Limp Y balance test and for explosive power with the medicine ball throw test. Moreover, the strength of the shoulder internal and external rotator muscles was measured with an isokinetic dynamometer at a speed of 60°/second. The study was registered on the Clinical Trials website by the number NCT04162886. RESULTS: A comparison between the groups showed significant differences in terms of dynamic balance and explosive power (P < .05), but not in terms of isokinetic muscle strength and body composition (P > .05). On the other hand, comparisons of the dynamic equilibrium, explosive power and isokinetic muscle strength parameters within the exercise group returned statistically different results (P < .05). CONCLUSIONS: The Thrower's Ten exercises represent an effective method to improve the balance on the upper extremity, explosive power and isokinetic strength in healthy sedentary individuals.


Assuntos
Terapia por Exercício/métodos , Força Muscular/fisiologia , Extremidade Superior/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Dinamômetro de Força Muscular , Comportamento Sedentário , Adulto Jovem
12.
Sports Biomech ; 19(6): 723-737, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32942954

RESUMO

The aim of this study was to understand if and how surface-induced vibrations and road bike damping affect short-term neuromuscular performance in cycling. Thirty cyclists (mass 75.9 ± 8.9 kg, height 1.82 ± 0.05 m, Vo2max 63.0 ± 6.8 ml/min/kg) performed steady-state and maximum effort tests with and without vibration exposure (front dropout: 44 Hz, 4.1 mm; rear dropout: 38 Hz, 3.5 mm) on a damped and a nondamped bike. Transmitted accelerations to the musculoskeletal system, activation of lower extremity muscles (gast. med., soleus, vast. med., rec. fem.) and upper body muscles (erec. spinae, deltoideus, tric. brachii), oxygen uptake, heart rate and crank power output were measured. The main findings indicate a transmission of vibration to the whole body, but since no major propulsive muscles increase their activation with vibration, the systemic energy demand increases only marginally with vibration. Damping reduces vibrations at the upper body, which indicates an increase in comfort, but has no effect on the vibration transfer to the lower extremities. Therefore, road bike damping does not affect neuromuscular response of the propulsive muscle groups and energy demand. Consequently, short-term power output does not increase with damping.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Meio Ambiente , Músculo Esquelético/fisiologia , Vibração , Aceleração , Fenômenos Biomecânicos , Estudos Transversais , Frequência Cardíaca/fisiologia , Humanos , Extremidade Inferior/fisiologia , Masculino , Músculo Esquelético/inervação , Consumo de Oxigênio/fisiologia , Tronco/fisiologia , Extremidade Superior/fisiologia
13.
J Vis Exp ; (162)2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32925893

RESUMO

To reach towards a seen object, visual information has to be transformed into motor commands. Visual information such as the object's color, shape, and size are processed and integrated within numerous brain areas, then ultimately relayed to the motor periphery. In some instances, a reaction is needed as fast as possible. These fast visuomotor transformations, and their underlying neurological substrates, are poorly understood in humans as they have lacked a reliable biomarker. Stimulus-locked responses (SLRs) are short latency (<100 ms) bursts of electromyographic (EMG) activity representing the first wave of muscle recruitment influenced by visual stimulus presentation. SLRs provide a quantifiable output of rapid visuomotor transformations, but SLRs have not been consistently observed in all subjects in past studies. Here we describe a new, behavioral paradigm featuring the sudden emergence of a moving target below an obstacle that consistently evokes robust SLRs. Human participants generated visually guided reaches toward or away from the emerging target using a robotic manipulandum while surface electrodes recorded EMG activity from the pectoralis major muscle. In comparison to previous studies that investigated SLRs using static stimuli, the SLRs evoked with this emerging target paradigm were larger, evolved earlier, and were present in all participants. Reach reaction times (RTs) were also expedited in the emerging target paradigm. This paradigm affords numerous opportunities for modification that could permit systematic study of the impact of various sensory, cognitive, and motor manipulations on fast visuomotor responses. Overall, our results demonstrate that an emerging target paradigm is capable of consistently and robustly evoking activity within a fast visuomotor system.


Assuntos
Atividade Motora/fisiologia , Músculos/fisiologia , Extremidade Superior/fisiologia , Percepção Visual/fisiologia , Adulto , Braço/fisiologia , Eletromiografia , Feminino , Humanos , Masculino , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Curva ROC , Tempo de Reação/fisiologia , Robótica , Análise e Desempenho de Tarefas , Fatores de Tempo
14.
PLoS One ; 15(9): e0238225, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915841

RESUMO

Positional information on the shoulder girdle (the clavicle and scapula) is important for a better understanding of the function of the upper limb in the locomotive system as well as its associated disease pathogenesis. However, such data are limited except for information on the axial position of the scapula. Here, we describe a three-dimensional reconstruction of the shoulder girdle including the clavicle and scapula, and its relationship to different landmarks in the body. Thirty-six human fetal specimens (crown-rump length range: 7.6-225 mm) from the Kyoto Collection were used for this study. The morphogenesis and three-dimensional position of the shoulder girdle were analyzed with phase-contrast X-ray computed tomography and magnetic resonance imaging. We first detected the scapula body along with the coracoid and humeral head at Carnegie stage 18; however, the connection between the body and coracoid was not confirmed at this stage. During development, all landmarks on the shoulder girdle remained at the same axial position except for the inferior angle, which implies that the scapula enlarged in the caudal direction and reached the adult axial position in the fetal period. The scapula body was rotated internally and in the upward direction at the initiation of morphogenesis, but in the fetal period the scapula body was different than that in the adult position. The shoulder girdle was located at the ventral side of the vertebrae at the time of initial morphogenesis, but changed its position to the lateral side of the vertebrae in the late embryonic and fetal periods. Such a unique position of the shoulder girdle may contribute to the stage-specific posture of the upper limb. Adequate internal and upward rotation of the scapula could help in reducing the shoulder width, thereby facilitating childbirth. The data presented in this study can be used as normal morphometric references for shoulder girdle evaluations in the embryonic and fetal periods.


Assuntos
Desenvolvimento Fetal/fisiologia , Amplitude de Movimento Articular/fisiologia , Articulação do Ombro/anatomia & histologia , Articulação do Ombro/fisiologia , Ombro/embriologia , Ombro/fisiologia , Crescimento e Desenvolvimento , Humanos , Ombro/anatomia & histologia , Extremidade Superior/anatomia & histologia , Extremidade Superior/fisiologia
15.
PLoS One ; 15(8): e0221668, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776927

RESUMO

BACKGROUND: Animal models of brain recovery identify the first days after lesioning as a time of great flux in sensorimotor function and physiology. After rodent motor system lesioning, daily skill training in the less affected forelimb reduces skill acquisition in the more affected forelimb. We asked whether spontaneous human motor behaviors of the less affected upper extremity (UE) early after stroke resemble the animal training model, with the potential to suppress clinical recovery. METHODS: This prospective observational study used a convenience sample of patients (n = 25, mean 4.5 ±1.8) days after stroke with a wide severity range; Controls were hospitalized for non-neurological conditions (n = 12). Outcome measures were Accelerometry, Upper-Extremity Fugl-Meyer (UEFM), Action Research Arm Test (ARAT), Shoulder Abduction/ Finger Extension Test (SAFE), NIH Stroke Scale (NIHSS). RESULTS: Accelerometry indicated total paretic UE movement was reduced compared to controls, primarily due to a 44% reduction of bilateral UE use. Unilateral paretic movement was unchanged. Thus, movement shifted early after stroke; bilateral use was reduced and unilateral use of the non-paretic UE was increased by 77%. Low correlations between movement time and motor performance prompted an exploratory factor analysis (EFA) revealing a 2-component solution; motor performance tests load on one component (motor performance) whereas accelerometry-derived variables load on a second orthogonal component (quantity of movement). CONCLUSIONS: Early after stroke, spontaneous overall UE movement is reduced, and movement shifts to unilateral use of the non-paretic UE. Two mechanisms that could influence motor recovery may already be in place 4.5 ± 1.8 days post stroke: (1) the overuse of the less affected UE, which could set the stage for learned non-use and (2) skill acquisition in the non-paretic limb that could impede recovery. Accurate UE motor assessment requires two independent constructs: motor performance and quantity of movement. These findings provide opportunities and measurement methods for studies to develop new behaviorally-based stroke recovery treatments that begin early after onset.


Assuntos
Atividade Motora/fisiologia , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/fisiopatologia , Acelerometria/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Destreza Motora/fisiologia , Movimento/fisiologia , Avaliação de Resultados em Cuidados de Saúde , Paresia/fisiopatologia , Paresia/terapia , Estudos Prospectivos , Recuperação de Função Fisiológica/fisiologia , Fatores de Tempo , Estados Unidos , Extremidade Superior/fisiologia
16.
J Sports Sci ; 38(20): 2298-2306, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32543283

RESUMO

This study estimated upper and lower limb bone mineral content (BMC) and bone area (BA) in 48 children tennis players (24 boys, 24 girls) aged 7-13 years. The sample comprised four age groups (8.2 ± 0.44, 9.5 ± 0.13, 10.5 ± 0.33, 12.2 ± 0.58). BMC and BA were measured via DXA, and sexual maturity by the Tanner scale, then used as a binary: prepubertal vs peripubertal. Total training time (TTT) included all playing years. Arms were asymmetric and legs symmetric. Boys were more asymmetric than girls in BMC (18% vs 13%) and BA (11% vs 8%). Pre-pubertal children were less asymmetric than peri-pubertal in BMC (14% vs 18%) and in BA (9.4% vs 10%). Bone growth changed with age and TTT markedly better in the dominant arm. The linear combination of TTT, sex, and maturity binary extracted 59% of BMC asymmetry and only 21% of BA asymmetry. For both bone parameters the sex effect was significant only for the pre-pubertal children. Training time constitutes the best predictor of bone asymmetry compared to age, sex, and maturity; when adequate, playing arm bone hypertrophy may be detectable at the age of 7-8 years. These results have health and performance implications.


Assuntos
Densidade Óssea , Desenvolvimento Ósseo/fisiologia , Extremidade Inferior/fisiologia , Condicionamento Físico Humano/fisiologia , Maturidade Sexual/fisiologia , Tênis/fisiologia , Extremidade Superior/fisiologia , Adolescente , Fatores Etários , Criança , Feminino , Humanos , Masculino , Puberdade/fisiologia , Análise de Regressão , Fatores Sexuais , Fatores de Tempo
17.
Sci Rep ; 10(1): 8464, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32440004

RESUMO

The aim of this study was to analyse the front-crawl arm-pull kinetics and kinematics, comparing it before and after post-activation potentiation (PAP), and the associations between variables describing of the arm-pull kinetics. Twelve male competitive swimmers were randomly assigned to perform two different warm-ups in a crossover manner: (i) non-PAP (control condition); and (ii) PAP (experimental condition). PAP consisted of 2 × 5 arm-pulls with resistance bands by both upper-limbs. Eight minutes later, participants underwent a 25 m all-out trial in front-crawl arm-pull. Kinetics (i.e., peak thrust, mean thrust and thrust-time integral) and kinematics (i.e., speed and speed fluctuation) were collected by an in-house customised system composed of differential pressure sensors, speedo-meter and underwater camera. There was a significant and large improvement of the arm-pull kinetics after completing the warm-up with PAP sets (0.010 < P < 0.054, 0.50 < d < 0.74). There were non-significant and small effects of PAP on speed (P = 0.307, d = 0.18) and speed fluctuation (P = 0.498, d = 0.04). Correlation coefficients among kinetic variables were significant with large associations (0.51 < R < 0.90, 0.001 < P < 0.088). In conclusion, warm-ups including PAP conditioning sets elicit a large improvement in the thrust, but with small improvement in performance. Variables used to characterise thrust are strongly correlated and hence can be used interchangeably.


Assuntos
Braço/fisiologia , Desempenho Atlético/fisiologia , Natação/fisiologia , Extremidade Superior/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Adulto Jovem
18.
J Neuroeng Rehabil ; 17(1): 63, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32404174

RESUMO

BACKGROUND: Human-likeliness of robot movements is a key component to enable a safe and effective human-robot interaction, since it contributes to increase acceptance and motion predictability of robots that have to closely interact with people, e.g. for assistance and rehabilitation purposes. Several parameters have been used to quantify how much a robot behaves like a human, which encompass aspects related to both the robot appearance and motion. The latter point is fundamental to allow the operator to interpret robotic actions, and plan a meaningful reactions. While different approaches have been presented in literature, which aim at devising bio-aware control guidelines, a direct implementation of human actions for robot planning is not straightforward, still representing an open issue in robotics. METHODS: We propose to embed a synergistic representation of human movements for robot motion generation. To do this, we recorded human upper-limb motions during daily living activities. We used functional Principal Component Analysis (fPCA) to extract principal motion patterns. We then formulated the planning problem by optimizing the weights of a reduced set of these components. For free-motions, our planning method results into a closed form solution which uses only one principal component. In case of obstacles, a numerical routine is proposed, incrementally enrolling principal components until the problem is solved with a suitable precision. RESULTS: Results of fPCA show that more than 80% of the observed variance can be explained by only three functional components. The application of our method to different meaningful movements, with and without obstacles, show that our approach is able to generate complex motions with a very reduced number of functional components. We show that the first synergy alone accounts for the 96% of cost reduction and that three components are able to achieve a satisfactory motion reconstruction in all the considered cases. CONCLUSIONS: In this work we moved from the analysis of human movements via fPCA characterization to the design of a novel human-like motion generation algorithm able to generate, efficiently and with a reduced set of basis elements, several complex movements in free space, both in free motion and in case of obstacle avoidance tasks.


Assuntos
Algoritmos , Movimento , Robótica/métodos , Extremidade Superior/fisiologia , Humanos , Movimento (Física) , Análise de Componente Principal
19.
Proc Natl Acad Sci U S A ; 117(21): 11364-11367, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32393618

RESUMO

We show that the human voice has complex acoustic qualities that are directly coupled to peripheral musculoskeletal tensioning of the body, such as subtle wrist movements. In this study, human vocalizers produced a steady-state vocalization while rhythmically moving the wrist or the arm at different tempos. Although listeners could only hear and not see the vocalizer, they were able to completely synchronize their own rhythmic wrist or arm movement with the movement of the vocalizer which they perceived in the voice acoustics. This study corroborates recent evidence suggesting that the human voice is constrained by bodily tensioning affecting the respiratory-vocal system. The current results show that the human voice contains a bodily imprint that is directly informative for the interpersonal perception of another's dynamic physical states.


Assuntos
Extremidade Superior/fisiologia , Voz/fisiologia , Adulto , Percepção Auditiva , Feminino , Audição/fisiologia , Humanos , Masculino , Atividade Motora/fisiologia , Experimentação Humana não Terapêutica , Punho/fisiologia
20.
Muscle Nerve ; 61(6): 708-718, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32413247

RESUMO

The loss of upper limb motor function can have a devastating effect on people's lives. To restore upper limb control and functionality, researchers and clinicians have developed interfaces to interact directly with the human body's motor system. In this invited review, we aim to provide details on the peripheral nerve interfaces and brain-machine interfaces that have been developed in the past 30 years for upper extremity control, and we highlight the challenges that still remain to transition the technology into the clinical market. The findings show that peripheral nerve interfaces and brain-machine interfaces have many similar characteristics that enable them to be concurrently developed. Decoding neural information from both interfaces may lead to novel physiological models that may one day fully restore upper limb motor function for a growing patient population.


Assuntos
Amputados/reabilitação , Pesquisa Biomédica/tendências , Robótica/tendências , Traumatismos da Medula Espinal/reabilitação , Extremidade Superior/fisiologia , Pesquisa Biomédica/métodos , Interfaces Cérebro-Computador/tendências , Previsões , Humanos , Robótica/métodos , Traumatismos da Medula Espinal/fisiopatologia
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