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1.
Brain Sci ; 14(2)2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38391752

RESUMO

Individuals with Parkinson's disease (PD) and freezing of gait (FOG) have a loss of presynaptic inhibition (PSI) during anticipatory postural adjustments (APAs) for step initiation. The mesencephalic locomotor region (MLR) has connections to the reticulospinal tract that mediates inhibitory interneurons responsible for modulating PSI and APAs. Here, we hypothesized that MLR activity during step initiation would explain the loss of PSI during APAs for step initiation in FOG (freezers). Freezers (n = 34) were assessed in the ON-medication state. We assessed the beta of blood oxygenation level-dependent signal change of areas known to initiate and pace gait (e.g., MLR) during a functional magnetic resonance imaging protocol of an APA task. In addition, we assessed the PSI of the soleus muscle during APA for step initiation, and clinical (e.g., disease duration) and behavioral (e.g., FOG severity and APA amplitude for step initiation) variables. A linear multiple regression model showed that MLR activity (R2 = 0.32, p = 0.0006) and APA amplitude (R2 = 0.13, p = 0.0097) explained together 45% of the loss of PSI during step initiation in freezers. Decreased MLR activity during a simulated APA task is related to a higher loss of PSI during APA for step initiation. Deficits in central and spinal inhibitions during APA may be related to FOG pathophysiology.

2.
Sensors (Basel) ; 23(14)2023 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-37514777

RESUMO

The principle of Fitts' law explains that the difficulty of movement increases when targets are farther away and narrower in width, particularly when touching two parallel targets as quickly as possible. Understanding the differences in motor and gaze behaviors between extroverts and introverts when performing tasks that require speed and accuracy is crucial for the development of sensor-based interfaces for games and rehabilitation. This study aimed to investigate such differences in a computer task that assesses the speed-accuracy trade-off (Fitts' task). Twenty introverts and seventeen extroverts wore an eye tracker and an accelerometer attached to their hand while performing 12 trials through six levels of difficulty presented on a computer screen. The results showed that introverts had longer visual fixations at the higher difficulty levels and reduced pupil diameter variability when difficulty was intermediate, suggesting that their gaze behavior may be different from that of extroverts. However, no significant differences were found in the speed and accuracy performance or kinematic variables between extroverts and introverts. These findings have important implications for the design of interventions that require both speed and accuracy in movement, such as in the development of virtual reality/games for rehabilitation purposes. It is important to consider individual differences in motor and gaze behaviors, particularly in those who may struggle with longer visual fixations, for the design of sensor-based applications and to promote successful interventions and recovery.


Assuntos
Extroversão Psicológica , Desempenho Psicomotor , Movimento , Personalidade , Computadores
3.
Gait Posture ; 96: 203-209, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35696826

RESUMO

BACKGROUND: The use of extra sources of sensory information associated with light fingertip touch to enhance postural steadiness has been associated with increased attentional demands, whereas the regularity of center of pressure (COP) fluctuations has been interpreted as a marker of the amount of attention invested in posture control. RESEARCH QUESTION: This study addressed whether increased attentional demands associated with postural tasks involving light finger touch might be reflected by measures of COP regularity. METHODS: The experiments involved quiet bipedal stance (n = 8 participants) and single-legged stance (n = 14 participants). Each participant was instructed to stand as quietly as possible on a force plate, either touching an external rigid surface (applied force < 1 N, light touch condition), or not (no touch condition). Postural steadiness was assessed by traditional COP measurements (COP Area, RMS, and velocity), whereas the regularity of postural sway was based on estimates of the sample entropy (SaEn) of the COP time series. RESULTS: Traditional parameters of postural sway and COP regularity (inversely related to SaEn COP measurements) were reduced during the touch conditions as compared to the no-touch conditions, for both bipedal quiet stance and single-legged stance. Decreased COP regularity with light touch was mainly reflected in the direction of the largest postural sway (i.e. in the sagittal plane for bipedal stance and in the frontal plane for single-legged stance). SIGNIFICANCE: The present results suggest that actively touching an external surface with the fingertip, besides increasing postural steadiness, generated an externally oriented (presumably cognitive-dependent) focus of attention, so that participants invested less attention on the postural task per se (as suggested by increased SaEn), which might be associated with a more "automatic" control of posture.


Assuntos
Perna (Membro) , Equilíbrio Postural , Atenção , Dedos , Humanos , Postura
4.
Front Physiol ; 13: 782838, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35222070

RESUMO

This study investigated whether expert acrobatic gymnasts respond differentially than their non-trained counterparts during a single-legged stance task performed before and after a protocol designed to induce fatigue in the ankle plantarflexor muscles in terms of (a) postural steadiness and (b) electromyography (EMG) activation. We hypothesized that neuromuscular adaptation due to training would lead to different behavior of center of pressure (COP) and EMG quantifiers after fatigue. Twenty eight female volunteers (aged 11 to 24 years) formed two groups: expert acrobatic gymnastics athletes (GYN, n = 14) and age-matched non-gymnasts [control (CTRL), n = 14]. Fatigue of the ankle plantarflexors (dominant leg) was induced by a sustained posture (standing on the toes) until exhaustion. Traditional COP parameters (area, RMS, mean velocity, and power spectrum at low and high frequency ranges) were obtained with a force plate, and time and frequency-domain EMG parameters were obtained by surface electrodes positioned on the tibialis anterior, soleus, lateral gastrocnemius, medial gastrocnemius, vastus lateralis, biceps femoris, spinal erector and rectus abdominis muscles. The main results showed that fatigue induced a significant increase in postural oscillations in the ML axis (including RMS, velocity and frequency components of the power spectrum), with no significant effects in the AP axis. In terms of postural sway parameters (i.e., COP quantifiers), no superior balance stability was found for the GYN group as compared to CTRL, irrespective of the fatigue condition. On the other hand, the modulation of EMG parameters (in both time and frequency domains) indicated that expert acrobatic gymnastics athletes (as compared to healthy untrained matched controls) used different neuromuscular control strategies to keep their postures on single-legged quiet standing after the fatiguing protocol. The present results improve our knowledge of the mechanisms behind the interplay between fatigue and postural performance associated with the neuromuscular adaptations induced by sport practice. The design of gymnastics training might consider strategies aimed at improving the performance of specific muscles (i.e., tibialis anterior, soleus, biceps femoris, spinal erector) for which particular activation patterns were used by the acrobatic gymnastics to control single-legged quiet standing.

5.
Games Health J ; 11(1): 38-45, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35104167

RESUMO

Objective: To verify if individuals' poststroke and healthy controls would improve their performance in reaction and movement times practicing a serious game task using the upper limb movements. Materials and Methods: We evaluated 30 individuals poststroke and 30 healthy controls, matched for age and sex. We used the "Association Game for Rehabilitation" (AGaR) where participants played by matching a pair of images whose meanings were similar. Hand movements were captured by a Kinect system and poststroke participants used their nonparetic upper limb. Reaction time and movement times (time to select an image and movement time to the target) were measured. Data were analyzed using multiple analysis of variance. Results: Performance improved for both groups across all variables with better performance in movement times than reaction time only for poststroke individuals. Conclusions: Upper limb movements using nonimmersive serious games enhanced motor performance in reaction and movement times for healthy controls and individuals poststroke. ReBEC Trial Registration: RBR-4m4pk; Registeted on 08/24/2018.


Assuntos
Acidente Vascular Cerebral , Jogos de Vídeo , Estudos Transversais , Mãos , Humanos , Movimento , Acidente Vascular Cerebral/complicações
8.
J Gerontol A Biol Sci Med Sci ; 76(4): 568-575, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33428714

RESUMO

Age-related changes in presynaptic inhibition (PSI) have not been observed during gait initiation, which requires anticipatory postural adjustment (APA). As APA is centrally modulated and is impaired in older compared to young adults, here we aimed to study the presynaptic control and co-contraction levels in the ankle muscles during gait initiation in older compared to young adults. Fifteen older (age range 65-80 years) and 15 young adults (age range 19-30 years) performed a gait initiation task on a force platform under 3 conditions: (i) without electrical stimulation; (ii) test Hoffman reflex (H-reflex); and (iii) conditioned H-reflex. H-reflexes were evoked on the soleus muscle when the APA amplitude exceeded 10%-20% of the average baseline mediolateral force. Participants also performed quiet stance as a control task. Results showed that both age groups presented similar PSI levels during quiet stance (p = .941), while in the gait initiation older adults presented higher PSI levels, longer duration, and lower amplitude of APA than young adults (p < .05). Older adults presented higher co-contraction ratio in both tasks than young adults (p < .05). Correlations between the PSI levels and the APA amplitude (r = -0.61, p = .008), and between the PSI levels and the co-contraction ratio during gait initiation (r = -0.64, p = .005) were found for older adults only. APA amplitude explained 49% of the variance of the PSI levels (p = .003). Our findings suggest that older compared to young adults have increased presynaptic control to compensate for the decreased supraspinal modulation on impaired APAs during gait initiation.


Assuntos
Envelhecimento/fisiologia , Marcha/fisiologia , Reflexo H/fisiologia , Equilíbrio Postural/fisiologia , Terminações Pré-Sinápticas/fisiologia , Adulto , Idoso , Estimulação Elétrica/métodos , Humanos , Músculo Esquelético/fisiologia , Reflexo Anormal , Análise e Desempenho de Tarefas
10.
Biomed Res Int ; 2020: 2937285, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32775414

RESUMO

OBJECTIVES: Sensory and motor alterations resulting from stroke often impair the performance and learning of motor skills. The present study is aimed at investigating whether and how poststroke individuals and age- and sex-matched healthy controls benefit from a contextual interference effect on the practice of a maze task (i.e., constant vs. random practice) performed on the computer. METHODS: Participants included 21 poststroke individuals and 21 healthy controls, matched by sex and age (30 to 80 years). Both groups were divided according to the type of the practice (constant or random) presented in the acquisition phase of the learning protocol. For comparison between the groups, types of practice, and blocks of attempts, the analysis of variance with Tukey's post hoc test (p < 0.05) was used. RESULTS: Poststroke individuals presented longer movement times as compared with the control group. In addition, only poststroke individuals who performed the task with random practice showed improved performance at the transfer phase. Moreover, randomized practice enabled poststroke individuals to perform the transfer task similarly to individuals without any neurological impairment. CONCLUSION: The present findings indicated a significant effect of contextual interference of practice in poststroke individuals, suggesting that applying randomized training must be considered when designing rehabilitation protocols for this population.


Assuntos
Aprendizagem/fisiologia , Destreza Motora/fisiologia , Movimento/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Computadores , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reabilitação do Acidente Vascular Cerebral/métodos , Análise e Desempenho de Tarefas
11.
J Physiol ; 598(8): 1611-1624, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32020612

RESUMO

KEY POINTS: Individuals with freezing of gait (FoG) due to Parkinson's disease (PD) have small and long anticipatory postural adjustments (APAs) associated with delayed step initiation. Individuals with FoG ('freezers') may require functional reorganization of spinal mechanisms to perform APAs due to supraspinal dysfunction. As presynaptic inhibition (PSI) is centrally modulated to allow execution of supraspinal motor commands, it may be deficient in freezers during APAs. We show that freezers presented PSI in quiet stance (control task), but they presented loss of PSI (i.e. higher ratio of the conditioned H-reflex relative to the test H-reflex) during APAs before step initiation (functional task), whereas non-freezers and healthy control individuals presented PSI in both the tasks. The loss of PSI in freezers was associated with both small APA amplitudes and FoG severity. We hypothesize that loss of PSI during APAs for step initiation in freezers may be due to FoG. ABSTRACT: Freezing of gait (FoG) in Parkinson's disease involves deficient anticipatory postural adjustments (APAs), resulting in a cessation of step initiation due to supraspinal dysfunction. Individuals with FoG ('freezers') may require functional reorganization of spinal mechanisms to perform APAs. As presynaptic inhibition (PSI) is centrally modulated to allow execution of supraspinal motor commands, here we hypothesized a loss of PSI in freezers during APA for step initiation, which would be associated with FoG severity. Seventy individuals [27 freezers, 22 non-freezers, and 21 age-matched healthy controls (HC)] performed a 'GO'-commanded step initiation task on a force platform under three conditions: (1) without electrical stimulation, (2) test Hoffman reflex (H-reflex) and (3) conditioned H-reflex. They also performed a control task (quiet stance). In the step initiation task, the H-reflexes were evoked on the soleus muscle when the amplitude of the APA exceeded 10-20% of the mean baseline mediolateral force. PSI was quantified by the ratio of the conditioned H-reflex relative to the test H-reflex in both the tasks. Objective assessment of FoG severity (FoG-ratio) was performed. Freezers presented lower PSI levels during quiet stance than non-freezers and HC (P < 0.05). During step initiation, freezers presented loss of PSI and lower APA amplitudes than non-freezers and HC (P < 0.05). Significant correlations were only found for freezers between loss of PSI and FoG-ratio (r = 0.59, P = 0.0005) and loss of PSI and APA amplitude (r = -0.35, P < 0.036). Our findings suggest that loss of PSI for step initiation in freezers may be due to FoG.


Assuntos
Transtornos Neurológicos da Marcha , Doença de Parkinson , Marcha , Transtornos Neurológicos da Marcha/etiologia , Humanos , Músculo Esquelético
12.
Spinal Cord ; 58(6): 635-646, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32066873

RESUMO

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: We aimed to investigate the effects of anodal transcranial direct current stimulation (tDCS) against sham on muscle strength and motor functionality after incomplete spinal cord injury (iSCI). SETTING: University of São Paulo, Brazil. METHODS: A preplanned protocol was registered (PROSPERO, CRD42016050444). Pubmed, Embase, Web of Science, Cochrane Central Library and BVS databases were searched independently by two authors up to March 2018. Cochrane Collaboration's Tool was used for the risk of bias assessments. Generic inverse variance and random-effects model were used to calculate pooled effect sizes (ES), 95% confidence intervals (CIs) and p-values in meta-analyses. RESULTS: Six randomized clinical trials met inclusion criteria (n = 78 iSCI individuals) and were included in the meta-analysis. Results showed a marginal significant pooled effect of active tDCS in improving motor functionality with a small ES (SMD = 0.26, 95% CI = -0.00 to 0.53, p = 0.05, I2 = 0%). On the other hand, the pooled effect of active tDCS on muscle strength did not reach statistical significance, in parallel with a small ES (SMD = 0.35, 95% CI = -0.21 to 0.92, p = 0.22, I2 = 0%) when compared with sham tDCS. No significant adverse events were reported. CONCLUSIONS: Overall, there was a significant effect of tDCS in improving motor functionality following iSCI. However, a small ES and the marginal p-value suggest that these results should be interpreted with caution. Further high-quality clinical trials are needed to support or refute the use of tDCS in daily clinical practice.


Assuntos
Força Muscular , Avaliação de Resultados em Cuidados de Saúde , Recuperação de Função Fisiológica , Traumatismos da Medula Espinal/reabilitação , Humanos , Força Muscular/fisiologia , Avaliação de Resultados em Cuidados de Saúde/normas , Recuperação de Função Fisiológica/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Estimulação Transcraniana por Corrente Contínua
13.
Autism Res ; 13(2): 307-319, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31566888

RESUMO

Autism spectrum disorder (ASD) is associated with persistent deficits in social communication and social interaction, including impaired multisensory integration, which might negatively impact cognitive and motor skill performance, and hence negatively affect learning of tasks. Considering that tasks in virtual environment may provide an engaging tool as adjuncts to conventional therapies, we set out to compare motor performance between young people with ASD and a typically developing (TD) control group that underwent coincident timing tasks based on Kinect (no physical contact) and on Keyboard (with physical contact) environments. Using a randomized repeated cross-over controlled trial design, 50 young people with ASD and 50 with TD, matched by age and sex were divided into subgroups of 25 people that performed the two first phases of the study (acquisition and retention) on the same device-real or virtual-and then switched to the other device to repeat acquisition and retention phases and finally switched on to a touch screen (transfer phase). Results showed that practice in the virtual task was more difficult (producing more errors), but led to a better performance in the subsequent practice in the real task, with more pronounced improvement in the ASD as compared to the TD group. It can be concluded that the ASD group managed to transfer the practice from a virtual to a real environment, indicating that virtual methods may enhance learning of motor and cognitive skills. A need for further exploration of its effect across a number of tasks and activities is warranted. Autism Res 2020, 13: 307-319. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Individuals with autism spectrum disorder are known to have difficulties with learning motor tasks. Considering that performing motor tasks in virtual environment may be an engaging tool as adjuncts to conventional therapies, we aimed to estimate performance in tasks regardless of physical touch. Results showed that participants had more difficulty using the non-touch task; however, virtual training improved performance on the physical (real) task. This result indicates that virtual methods could be a promising therapeutic approach for the ASD population.


Assuntos
Transtorno do Espectro Autista/fisiopatologia , Destreza Motora/fisiologia , Realidade Virtual , Adolescente , Fatores Etários , Transtorno do Espectro Autista/psicologia , Criança , Estudos Cross-Over , Feminino , Humanos , Masculino , Estudos Prospectivos , Fatores Sexuais
14.
Rev. bras. cineantropom. desempenho hum ; 22: e72276, 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1137213

RESUMO

Abstract The understanding of fatigue development during Archery competition would guide sports scientists, coaches and athletes on how to optimize the training routines of athletes from different competitive levels. This study investigated the effect of expertise level on physiological responses, during simulated archery competition (double-round 70m, 12 series, 6 arrows for an elite Brazilian Archer (EA) and a Novice Archer (NA). Ratings of perceived exertion, blood lactate and glucose, handgrip strength and electromyography were registered at the beginning, after each set from the 2nd to the 12tharrow and, 30-min after the competition simulation. The EA showed a greater handgrip strength for both arms, a constant lower mean RMS value (Baseline 0.279V and 12th set 0.221V, -20.7%), and a stable MF value throughout the competition (Baseline 146Hz to 12th set 140Hz). The NA showed a smaller handgrip strength, an increase in RMS after the 6th set towards the end of the competition (Baseline 0.387V, 6th 0.576V, and 12th set 0.720V, +46.2%) and a minor decrease in MF from the 6th to the end of 12th set (2nd set 122Hz, 4th set 127Hz, 6th set 112Hz and 12th set 117Hz, - 4.1%). In summary, all the fatigue-related markers showed a mild response to the Archery competition simulation, although a greater magnitude was observed in the NA, compared to the EA. This study reported the physiologic demands of an Archery simulated competition, in an official format, allowing coaches and sport scientists to draw more confident decisions on competition strategy and training design.


Resumo O entendimento da fadiga durante a competição de Tiro com Arco pode auxiliar na otimização da rotina de treinamento de atletas em diferentes níveis competitivos. Este estudo investigou o efeito do nível de experiência do atleta sobre as respostas fisiológicas, durante competição simulada de Tiro com Arco para um atleta de elite (EA) e um arqueiro iniciante (NA). Esforço percebido, concentração de lactato e glicose sanguínea, força de preensão manual e eletromiografia foram registrados no início, após cada série e, 30-min após a simulação. O EA apresentou maior força de preensão manual para ambos braços, valor de média RMS constantemente mais baixo (Baseline 0,279V e 12ª série 0,221V, -20,7%), e valor de MF estável no decorrer da competição (Baseline 146Hz a 12a série 140Hz). O NA demonstrou menor força de preensão manual, aumento na RMS após a 6a série até o final da competição (Baseline 0,387V, 6a 0,576V, and 12a série 0,720V, +46,2%) e pequena diminuição na MF da 6ª até o final da 12ª série (2a série 122Hz, 4a série 127Hz, 6a série 112Hz e 12a série 117Hz, - 4,1%). Assim, todos os marcadores relacionados a fadiga apresentaram resposta discreta na simulação de competição de Tiro com Arco, com maior magnitude no NA, em comparação com EA. Este estudo apresentou as demandas fisiológicas da competição simulada de Tiro com Arco, no formato oficial, permitindo que treinadores e cientistas do esporte possam tomar decisões com maior confiança sobre estratégias de competição e treinamento.

15.
Biomed Res Int ; 2019: 7106951, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31828120

RESUMO

BACKGROUND: Spinal cord injury (SCI) is often associated with long-term impairments related to functional limitations in the sensorimotor system. The use of virtual reality (VR) technology may lead to increased motivation and engagement, besides allowing a wide range of possible tasks/exercises to be implemented in rehabilitation programs. The present review aims to investigate the possible benefits and efficacy of VR-based rehabilitation in individuals with SCI. METHODS: An electronically systematic search was performed in multiple databases (PubMed, BVS, Web of Science, Cochrane Central, and Scielo) up to May 2019. MESH terms and keywords were combined in a search strategy. Two reviewers independently selected the studies in accordance with eligibility criteria. The PEDro scale was used to score the methodological quality and risk of bias of the selected studies. RESULTS: Twenty-five studies (including 482 participants, 47.6 ± 9.5 years, 73% male) were selected and discussed. Overall, the studies used VR devices in different rehabilitation protocols to improve motor function, driving skills, balance, aerobic function, and pain level, as well as psychological and motivational aspects. A large amount of heterogeneity was observed as to the study design, VR protocols, and outcome measures used. Only seven studies (28%) had an excellent/good quality of evidence. However, substantial evidence for significant positive effects associated with VR therapy was found in most of the studies (88%), with no adverse events (88%) being reported. CONCLUSION: Although the current evidence is limited, the findings suggest that VR-based rehabilitation in subjects with SCI may lead to positive effects on aerobic function, balance, pain level, and motor function recovery besides improving psychological/motivational aspects. Further high-quality studies are needed to provide a guideline to clinical practice and to draw robust conclusions about the potential benefits of VR therapy for SCI patients. Protocol details are registered on PROSPERO (registration number: CRD42016052629).


Assuntos
Traumatismos da Medula Espinal/reabilitação , Telerreabilitação , Realidade Virtual , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
16.
Somatosens Mot Res ; 36(4): 241-248, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31583939

RESUMO

This study examined the association between plantarflexion torque variability during quiet bipedal standing (QS) and during plantarflexion force- and position-matching tasks (FT and PT, respectively). In QS, participants stood still over a force plate, and the mean plantarflexion torque level exerted by each subject in QS (divided by 2 to give the torque due to a single leg) served as the target torque level for right leg FT and PT (performed with the participants seated with their right knee fully extended). During FT participants controlled the force level exerted by the foot against a rigid restraint, while during PT they controlled the angular position of the ankle when sustaining equivalent inertial loads. Standard deviation (SD) of plantarflexion torque was computed from torque signals acquired during periods with and without visual feedback. Significant correlations were found between plantarflexion torque variability in QS and FT (r = 0.8615, p < 0.0001 and r = 0.8838, p = 0.0003 for visual and no visual conditions, respectively) as well as between QS and PT (r = 0.8046, p = 0.003 and r = 0.7332, p = 0.0103 for visual and no visual conditions, respectively), regardless of vision availability. No significant differences were found between the correlations for Qs vs FT and QS vs PT (t(8) = 0.4778, p = 0.6455 and t(8) = 1.6819, p = 0.1310 for visual and no visual conditions, respectively), as assessed by "Hotelling-Williams" tests for equality among dependent correlations. The results indicate that simple measurements of plantarflexion torque fluctuations during FT and PT may be used to estimate balance ability. From a practical standpoint, it is suggested that rehabilitation protocols designed to regain/improve balance function may be based on the performance of FTs or PTs executed in a seated position.


Assuntos
Fenômenos Biomecânicos/fisiologia , Retroalimentação Sensorial/fisiologia , Pé/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologia , Adulto , Humanos , Torque
17.
Front Physiol ; 10: 1072, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507441

RESUMO

The details of how light touch (LT) of a stable surface reduces postural sway are still not well known. We hypothesized that removal of feedback provided by muscle afferents of the touching fingertip would increase postural sway in standing subjects. Eleven participants stood upright on a force plate with eyes closed and on an unstable surface. The experimental conditions involved two different finger positions: with partial muscle afferents (PMA), which includes sensory information from the fingertip flexor muscles, and no muscle afferents (NMA), without information from either fingertip flexor or extensor muscles. In the control condition, the participants kept the same posture, but with no finger touch (NT). Postural sway in both anteroposterior (AP) and mediolateral (ML) axes were recorded. Results showed that LT decreased all sway quantifiers as compared with the NT condition. The withdrawal of information from the touch finger muscle afferents (NMA condition) did not increase postural sway. Actually, there was a small, albeit statistically significant, decrease in the variability of center of pressure displacement in the AP direction. These results indicate that in some cases, muscle afferent input may either not contribute or even worsen the overall quality of sensory feedback from a given body segment, leading to no improvement or even a slightly decreased performance of the motor control system (evaluated by means of levels of postural sway in the present investigation). The results suggest that non-spindle fingertip afferents provide the bulk of the sensory feedback associated with the fingertip that is touching a ground-referenced object during quiet standing under LT.

18.
PLoS One ; 13(10): e0205553, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304030

RESUMO

The present study aimed at investigating whether the neuromuscular system behaves differently (in terms of force and muscle activity generation) as a function of the task being performed (i.e. maximal voluntary efforts vs stair negotiation) and the presence of patellofemoral pain (PFP) and possible influences of pain intensity. Thirty-eight women with (n = 19) and without PFP (n = 19) had their knee strength (extension joint torque) measured during maximal voluntary isometric contractions (MVIC) and electromyography (EMG) data recorded during both MVIC and stair ascent tasks, which were performed before and after a loading protocol designed to exacerbate pain symptoms. Women with PFP displayed lower levels of vastus medialis (p = 0.002) and vastus lateralis (p = 0.032) EMG activation during MVIC assessments. Conversely, the PFP group showed higher levels of vastus medialis muscle activity during stair climbing (p = 0.007), which happened exclusively after the loading protocol. Similarly, women with PFP displayed lower knee extensor torque only during the MVIC tests performed after the loading protocol, which was moderately correlated with the increase in self-reported pain (p = 0.041, r = 0.37), whereas the changes in EMG activity during stair ascent were not correlated with changes in pain intensity (p = 0.215, r = 0.12). These results suggest that, in comparison to pain-free controls, women with PFP display lower levels of quadriceps EMG activation during maximal contractions, but higher activation during dynamic tasks (stair ascent). In addition, the moderate association between the decrease in knee extensor torque and increase in self-reported pain indicates that care should be taken by clinicians during quadriceps strength evaluation in women with PFP, as misleading outcomes may emerge if the intensity of knee pain is not considered during screening. Additionally, rehabilitation strategies should focus on both restoring neuromuscular control and increasing muscle strength.


Assuntos
Contração Isométrica/fisiologia , Síndrome da Dor Patelofemoral/fisiopatologia , Músculo Quadríceps/fisiopatologia , Subida de Escada/fisiologia , Fenômenos Biomecânicos , Eletromiografia , Feminino , Humanos , Articulação do Joelho , Força Muscular/fisiologia , Medição da Dor , Torque , Volição , Adulto Jovem
19.
Rev. bras. med. esporte ; Rev. bras. med. esporte;24(3): 225-229, May-June 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-959063

RESUMO

ABSTRACT Introduction: Extraversion/introversion and age differences might influence speed-accuracy tradeoff. Objective: The speed-accuracy tradeoff was investigated in extroverted and introverted female children, young adults and older adults. Method: Participants carried out an alternative version of Fitts' task, which involved making alternate clicks with the mouse held in the dominant hand, moving as fast as possible, on two rectangular targets on a computer screen in order to make twelve attempts at six random levels of difficulty (twelve combinations of target widths and distances between targets). Each of the three groups was composed of 16 introverted and 16 extroverted subjects, based upon Brazilian versions of Eysenck's questionnaire. Results: Elderly introverts fell short of the target more often and committed more overall errors than the elderly extroverts. Additionally, compared to their younger adult counterparts, the elderly subjects fell short of the target more often and committed more overall errors, besides taking longer to complete the task with higher levels of difficulty. Conclusion: The findings were interpreted in light of theories designed to explain the main processes underlying extroversion/introversion and age-related differences. Level of Evidence II; Lesser quality prospective study.


RESUMO Introdução: Diferenças de extroversão/introversão e idade podem influenciar na troca velocidade-precisão. Objetivo: A troca velocidade-precisão foi investigada em garotas, jovens adultas e idosas extrovertidas e introvertidas. Método: As participantes realizaram uma versão alternativa da tarefa de Fitts, a qual consistia em clicar alternadamente com a mão dominante no mouse, o mais rápido possível, em dois alvos retangulares na tela do computador, a fim de fazer doze tentativas em seis níveis aleatórios de dificuldade (doze combinações de larguras e distâncias entre os alvos). Cada um dos três grupos era composto por 16 introvertidas e 16 extrovertidas, com base nas versões brasileiras do questionário de Eysenck. Resultados: As idosas introvertidas acertaram menos o alvo com mais frequência e cometeram mais erros gerais em comparação às idosas extrovertidas. Ainda, as idosas acertaram menos o alvo com mais frequência e cometeram mais erros gerais, além de demorarem mais tempo para concluírem as tarefas com níveis maiores de dificuldade quando comparadas com as jovens adultas. Conclusão: Os achados foram interpretados com base nas teorias criadas para explicarem os principais processos sobre as diferenças relacionadas à extroversão/introversão e à idade. Nível de Evidência II; Estudo prospectivo de menor qualidade.


RESUMEN Introducción: Las diferencias de extroversión/introversión y edad pueden influir en el cambio velocidad-precisión. Objetivo: El cambio velocidad-precisión fue investigado en mujeres jóvenes adultas y de la tercera edad introvertidas y extrovertidas. Método: Las participantes realizaron una versión alternativa de la tarea de Fitts, que consistía en hacer clic alternadamente con el ratón, usando la mano dominante, lo más rápidamente posible, en dos objetos rectangulares en la pantalla de la computadora, a fin de realizar doce tentativas con seis niveles aleatorios de dificultad (doce combinaciones de anchos y distancias entre los objetos). Cada uno de los tres grupos fue compuesto por 16 introvertidas y 16 extrovertidas, con base en las versiones brasileñas del cuestionario de Eysenck. Resultados: Las mujeres de tercera edad introvertidas acertaron menos el objeto con más frecuencia y cometieron más errores generales en comparación a las mujeres de tercera edad extrovertidas. Además, las mujeres de tercera edad acertaron menos el objeto con más frecuencia y cometieron más errores generales, además de demorar más tiempo para concluir las tareas con niveles mayores de dificultad cuando comparadas con las mujeres jóvenes adultas. Conclusión: Los hallazgos fueron interpretados con base en las teorías creadas para explicar los principales procesos sobre las diferencias relacionadas a la extroversión/la introversión y a la edad. Nivel de Evidencia II; Estudio prospectivo de menor calidad.

20.
Dement Neuropsychol ; 11(3): 276-286, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29213525

RESUMO

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder primarily characterized by deficits in social interaction, communication and implicit skill learning. OBJECTIVE: To analyse the results of research on "motor learning" and the means used for measuring "autistic disorder". METHODS: A systematic literature search was done using Medline/PubMed, Web of Science, BVS (virtual health library), and PsycINFO. We included articles that contained the keywords "autism" and "motor learning". The variables considered were the methodological aspects; results presented, and the methodological quality of the studies. RESULTS: A total of 42 studies were identified; 33 articles were excluded because they did not meet the inclusion criteria. Data were extracted from nine eligible studies and summarized. CONCLUSION: We concluded that although individuals with ASD showed performance difficulties in different memory and motor learning tasks, acquisition of skills still takes place in this population; however, this skill acquisition is related to heterogeneous events, occurring without the awareness of the individual.


O Transtorno do Espectro Autista (TEA) é uma desordem do desenvolvimento neurológico caracterizada principalmente por déficits na interação social, comunicação e aprendizagem de habilidades implícitas. OBJETIVO: Analisar os resultados da pesquisa sobre "aprendizagem motora" e suas formas de mensurar na "desordem autista". MÉTODOS: Uma pesquisa bibliográfica sistemática foi feita usando Medline/PubMed, Web of Science, BVS (biblioteca virtual de saúde) e PsycINFO. Incluímos artigos que mostraram as palavras-chave "autismo" e "aprendizagem motora". As variáveis consideradas foram os aspectos metodológicos; os resultados apresentados e a qualidade metodológica dos estudos. RESULTADOS: Um total de 42 artigos foram identificados; foram excluídos 33 artigos porque não atendiam aos critérios de inclusão. Os dados foram extraídos de nove estudos elegíveis e resumidos. CONCLUSÃO: Concluímos que, embora as pessoas com TEA tenham demonstrado dificuldades de desempenho em diferentes tarefas de aprendizagem motora de memória, a aquisição de habilidades ocorre nessa população; No entanto, essa aquisição de habilidades está relacionada a eventos heterogêneos, ocorrendo sem a consciência dos indivíduos.

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