ABSTRACT
ObjectiveTo investigate the individual factors of postural adjustment reaction time and movement time during adaptive equilibrium. MethodsFrom March to December, 2021, 126 healthy adults aged 18 to 80 years were recruited at the First Medical Center of the General Hospital of the Chinese PLA. The DE-A somatosensory balance detection system was used to detect their postural adjustment reaction time (RT) and movement time (MT) as the platform tilting in multiple directions during standing (static) or walking (dynamic). The ages, genders, body mass index (BMI) and physical activity level of them were investigated. ResultsThe age was the only factor independently associated with dynamic RT and MT in all the directions (β > 0.632, P < 0.05). For static MT, as the platform tilting forward, physical activity level (β = -0.143, P < 0.05), BMI (β = 0.154, P < 0.05) and age (β = 0.663, P < 0.05) were the independently associated factors; as the platform tilting leftward, gender (β = -0.173, P < 0.05) and age (β = 0.647, P < 0.05) were the independently associated factors; and age was the only independently associated factor for other directions (β > 0.571, P < 0.05). For the static RT, age was the only independently associated factor for all the directions (β > 0.615, P < 0.05). ConclusionAge is the most important independently factor related to postural adjustment during adaptive equilibrium, and aging may delay the postural adjustment after instability.
ABSTRACT
There is evidence that the left hemisphere is more competent for motor control than the right hemisphere. This study investigated whether this hemispheric asymmetry is expressed in the latency/duration of sequential responses performed by the left and/or right hands. Thirty-two right-handed young adults (16 males, 16 females; 18-25 years old) were tested in a simple or choice reaction time task. They responded to a left and/or right visual target by moving their left and/or right middle fingers between two keys on each side of the midline. Right hand reaction time did not differ from left hand reaction time. Submovement times were longer for the right hand than the left hand when the response was bilateral. Pause times were shorter for the right hand than the left hand, both when the responses were unilateral or bilateral. Reaction time results indicate that the putatively more efficient response preparation by the left hemisphere motor mechanisms is not expressed behaviorally. Submovement time and pause time results indicate that the putatively more efficient response execution by the left hemisphere motor mechanisms is expressed behaviorally. In the case of the submovements, the less efficient motor control of the left hand would be compensated by a more intense attention to this hand.
Subject(s)
Adolescent , Adult , Female , Humans , Male , Young Adult , Attention/physiology , Functional Laterality/physiology , Hand/physiology , Orientation/physiology , Psychomotor Performance/physiology , Reaction Time/physiologyABSTRACT
The effects of target location and uncertainty of target position on reaching movements while standing were investigated. Ten healthy, right-handed adults stood facing a 17'' touchscreen. They were instructed to press with their right index fingertip a push bottom and touch the center of the target displayed on the screen after it was lighted on, moving quickly their arm. The target was shown either ipsi- or contralateral to the right arm and either in a certain or uncertain position. Reaction time (RT), movement time (MT), and radial error (RE) were assessed. Results revealed shorter RT (≈ 35 ms) and smaller RE (≈ 0.19 cm) for certain than for uncertain condition and slightly longer RT (≈ 8 ms) and MT (≈ 18 ms) for reaches towards the contralateral target. In conclusion, the findings of this study showing the effect of uncertainty of target location as well as target position are also applied to arm reaching in standing position.
Os efeitos da localização do alvo e da incerteza quanto à posição do alvo em movimentos de alcance foram investigados. Dez adultos permaneceram em pé em frente a um monitor sensível ao toque. Eles foram instruídos a pressionar com o dedo indicador direito um interruptor e tocar o centro do alvo apresentado no monitor após ele acender, movendo o membro superior rapidamente. O alvo foi mostrado ipsi ou contralateralmente e os participantes tinham ou não certeza sobre a posição do alvo. O tempo de reação (TR) e movimento (TM) e o erro radial (ER) foram avaliados. Os resultados revelaram menor TR (≈35 ms) e ER (≈0,19 cm) para a condição de certeza e maiores TR (≈8 ms) e TM (≈18 ms) para os moimentos ao alvo contralateral. Concluindo, esses achados mostraram que os efeitos da incerteza da localização e a posição final do alvo podem ser aplicados para movimentos de alcance na posição ereta.
Los efectos de la ubicación de la diana y la incertidumbre acerca de la posición de la diana en los movimientos de alcance fueron investigados. Diez adultos sanos y diestros estaban frente a una pantalla táctil de 17''. Se les instruyó para presionar un interruptor con el dedo índice derecho y tocar el centro de la diana que aparece en la pantalla después de haber sido iluminado, moviéndo rápidamente su miembro superior. La diana fue mostrada ya sea ipsi o contralateralmente y los participantes tenían o no certidumbre sobre la posición de la misma. El tiempo de reacción (TR), el tiempo de movimiento (TM), y el error radial (ER) fueron evaluados. Los resultados revelaron ser más cortos TR (≈ 35 ms) y RE menor (≈ 0,19cm) en la condición de certeza y mayores TR (≈ 8 ms) y TM (≈ 18 ms) en los movimientos hacia la meta contralateral. En conclusión, los hallazgos de este estudio que muestra los efectos de la incertidumbre de la ubicación de la diana, así como la posición de la diana se aplican también a movimientos de alcance en la posición erecta.
Subject(s)
Humans , Male , Adult , Movement , Reaction Time , Uncertainty , Upper ExtremityABSTRACT
O badminton é um esporte no qual os atletas devem responder a golpes rápidos e potentes de maneira acurada. Assim, o objetivo do estudo foi investigar se jogadores de badminton de alto nível apresentam melhores índices de desempenho neuromuscular do que jogadores de nível intermediário na tarefa de apontar um alvo. Doze jogadores de alto nível (GAN), que defendem ou defenderam a seleção brasileira de badminton, e 12 jogadores de nível intermediário (GNI) participaram do estudo. Eles permaneceram em pé, com o dedo indicador da mão dominante sobre um interruptor localizado à frente e direcionado à linha média do corpo, e foram instruídos a tocar um alvo em uma tela sensível ao toque posicionada à frente assim que ele se tornasse luminoso. O alvo foi apresentado ipsilateralmente ou contralateralmente ao membro superior dominante, em blocos (tempo de reação simples) ou randomicamente (tempo de reação de escolha). As variáveis tempo de reação (TR), tempo de movimento (TM) e erro radial (ER) foram computadas. Os resultados não revelaram efeito de grupo para TM e ER, mas revelaram que o GAN apresentou TR menor que o GNI. Ainda, o TR foi menor para a condição em blocos e o TR e o TM foram menores para o alvo ipsilateral. O fato de o GAN apresentar TR menor que o GNI indica que jogadores de alto nível teriam melhor capacidade reativa que jogadores de níveis inferiores. Assim, concluímos que o TR poderia ser uma variável importante na seleção de atletas que teriam maiores chances de alcançar altos níveis de desempenho no badminton. Ainda, apesar de o teste utilizado não representar integralmente as ações de jogo, ele é um avanço quando comparado aos testes comumente utilizados na investigação do TR e TM em atletas e deveria ser utilizado na avaliação de atletas de outros esportes.
Badminton is a racket sport where athletes have to accurately react to powerful and rapid strokes from their opponents. Therefore, the aim of the study was to investigate whether expert badminton players (members of the national team) would present better indices of neuromuscular performance than intermediate level badminton players in a target-pointing task. Twelve expert badminton players (EPG), who currently play or have already played for the Brazilian national team, and 12 intermediate-level players (IPG) participated in the study. The standing participant was instructed to press a switch placed in front of him and at his midline with the tip of the index finger and touch a target displayed in a touch screen located in front of him as soon as this target was lighted. The target was shown either ipsi- or contralateral to the dominant upper limb and either in blocks (simple reaction time - SRT) or randomly (choice reaction time - CRT). The dependent variables reaction time (RT), movement time (MT), and radial error (RE) were calculated. The results revealed no effect of group on MT and RE, but revealed that RT was shorter for EPG than for IPG. Moreover, RT was lower in SRT than in CRT condition and RT and MT was lower when the target was ipsilaterally presented and during STR condition. The shorter RT presented by expert badminton players when compared to intermediate level players could indicate that RT could be a key neuromuscular variable to distinguish expert from non-expert badminton players. Finally, although the experimental protocol does not integrally represent the actions performed during the game, it is a progress when compared to the tests commonly used to investigate the response time (RT and MT) in athletes, and should be used to assess those neuromuscular variables in athletes of sports that use the upper extremity.
ABSTRACT
This study investigated the influence of cueing on the performance of untrained and trained complex motor responses. Healthy adults responded to a visual target by performing four sequential movements (complex response) or a single movement (simple response) of their middle finger. A visual cue preceded the target by an interval of 300, 1000, or 2000 ms. In Experiment 1, the complex and simple responses were not previously trained. During the testing session, the complex response pattern varied on a trial-by-trial basis following the indication provided by the visual cue. In Experiment 2, the complex response and the simple response were extensively trained beforehand. During the testing session, the trained complex response pattern was performed in all trials. The latency of the untrained and trained complex responses decreased from the short to the medium and long cue-target intervals. The latency of the complex response was longer than that of the simple response, except in the case of the trained responses and the long cue-target interval. These results suggest that the preparation of untrained complex responses cannot be completed in advance, this being possible, however, for trained complex responses when enough time is available. The duration of the 1st submovement, 1st pause and 2nd submovement of the untrained and the trained complex responses increased from the short to the long cue-target interval, suggesting that there is an increase of online programming of the response possibly related to the degree of certainty about the moment of target appearance.
Subject(s)
Adolescent , Adult , Female , Humans , Male , Young Adult , Cues , Conditioning, Psychological/physiology , Movement/physiology , Photic Stimulation/methods , Reaction Time/physiologyABSTRACT
Purpose : To investigate the cooling effect on muscles prior to continuous isometric muscle contraction. Furthermore, tissue compliance, pressure pain threshold, deep tissue temperature, and tissue circulation volume were measured to investigate the cooling effect on a physical reaction. Method : The biceps brachii muscle was contracted isometrically and continuously at the 90(-) degree in flexion position with 40% of maximum contraction. The task was ceased when subjects could not keep over 70 degrees of elbow flexion. An injection type cooling stimulator was used on the biceps brachii muscle as a cooling modality. Results : The continuous contraction time in the cooled group increased significantly compared with the control group. In addition, tissue compliance and pressure pain threshold showed significant differences between the two groups. Conclusion : This study suggested that the isometric continuous contraction time in cooled muscles can be extended to 40% of MVC. The inhibition of muscle metabolism, an increase in the pressure pain threshold, and tissue compliance may affect muscle endurance.
ABSTRACT
Objective To study the characteristics of pointing movement time for targets with different position in front of human body,to detect the effects of targets location on pointing movement time.Methods A pointing movement experiment of human arm was designed and carried out.By the statistic analysis of the experimental data,the relationship between pointing movement time and target position was discussed.Results It was shown that the starting point position and target position extremely affected the pointing movement time.Conclusion When a right-handed person touches the different targets,both the direction to target and the starting point position(target-circle location) would affect the pointing movement time extremely.When the position of the starting point changed by horizontal or vertical,the pointing movement time is more changeful by horizontal than that by vertical.To compare the pointing movement time for each target on a target-circle,the pointing movement time for right-upper target is the shortest.When the starting point is located on the right side of human body,all pointing movement time of that target-circle is the shortest.