Deciphering the nature of the joint Simon effect through electromyographic analyses

This study aimed to apply electromyographic techniques and distributional analyses to test whether an increase in the strength of stimulus-response mapping could explain the mechanisms underlying the joint Simon effect. Within a single protocol, participants performed a Simon task and a Go/NoGo task in isolation, and a joint Go/NoGo task with a co-actor (joint Simon task). Results showed that joint-action impairs cognitive control and shortened reaction time by impacting both pre-motor time and motor time. Joint-action induced a larger facilitation on pre-motor time of ipsilateral than contralateral associations. This potentiation of the spatial correspondence effect plausibly explains the larger Simon-like effect usually observed in the joint Go/NoGo task compared to that observed in the isolated Go/NoGo task. The propensity of making incorrect activations and their concentration among fast responses also increased when working co-actively. Together, these findings indicate that joint-action increases the strength of automatic response capture induced by the stimulus location, promotes the delivery of the stronger association in the behavioral repertoire of the individual, and reduces cognitive control.

EFFECTS OF HIGH-SPEED POWER TRAINING ON NEUROMUSCULAR AND GAIT FUNCTIONS IN FRAIL ELDERLY WITH MILD COGNITIVE IMPAIRMENT DESPITE BLUNTED EXECUTIVE FUNCTIONS: A RANDOMIZED CONTROLLED TRIAL

Background: Physical frailty and impaired executive function of the brain show similar pathophysiology. Both of these factors lead to dysfunction of neuromuscular and abilities in elderly. High-speed power training (HSPT) has been determined to have positive effects on neuromuscular function and gait performance, as well as executive function in the elderly. Objectives: The purpose of this study was to investigate the effects of 8-week HSPT on neuromuscular, gait and executive functions in frail elderly with mild cognitive impairment (MCI). Design, setting and participants: We performed a randomized controlled trial of frail elderly from community and medical center in republic of Korea. Forty-two physically frail elderly with MCI were randomly allocated to control (n=22, age=74.22±4.46) and intervention groups (n=18, age=73.77±4.64). The intervention group was subjected to HSPT, 3 times weekly for 8 weeks. Measurements: Isometric contraction of knee extension and flexion with electromyography (EMG) was measured to determine the neuromuscular function such as knee extensor strength, rate of torque development, movement time, pre-motor time, motor time, rate of EMG rise, and hamstrings antagonist co-activation. Additionally, the 4.44-meter gait and timed up-and-go (TUG) test were administered to assess gait performance. A frontal assessment battery was measured in this study. Results: The 8-week HSPT regimen improved the knee extensor strength from 1.13±0.08 to 1.25±0.07 (p<0.05), the 200-ms RTD from 3.01±0.3 to 3.55±0.24 (p<0.05) and the rate of EMG rise from 166.48±13.31 to 197.94±11.51 (p<0.05), whereas the movement time and motor time were statistically decreased from 921.69±40.10 to 799.51±72.84, and 271.40±19.29 to 181.15±38.08 (p<0.05), respectively. The 4.44-m gait speed and TUG significantly decreased from 6.39±0.25 to 5.5±0.24, and 11.05±0.53 to 9.17±0.43 respectively (p<0.05). Conclusion: The findings of this study suggest the favorable effects of 8-week HSPT on the neuromuscular function and the gait performance in the frail elderly with MCI without increase in the executive function.

A reconfigurable multi-mode walking-rolling robot based on motor time-sharing control

Purpose The purpose of this paper is to put forward a nvew reconfigurable multi-mode walking-rolling robot based on the single-loop closed-chain four-bar mechanism, and the robot can be changed to different modes according to the terrain. Design/methodology/approach Based on the topological analysis, singularity analysis, feasibility analysis, gait analysis and the motion strategy based on motor time-sharing control, the paper theoretically verified that the robot can switch between the four motion modes. Findings The robot integrates four-bar walking, self-deforming and four-bar and six-bar rolling modes. A series of simulation and prototype experiment results are presented to verify the feasibility of multiple motion modes of the robot. Originality/value The work presented in this paper provides a good theoretical basis for further exploration of multiple mode mobile robots. It is an attempt to design the multi-mode mobile robot based on single loop kinematotropic mechanisms. It is also a kind of exploration of the new unknown movement law.

Influencia del bilingüismo en el tiempo de compromiso motor en Educación Física (Influence of bilingualism on engagement motor time in Physical Education)

El objetivo de la presente investigación es analizar la relación existente entre la introducción de planteamientos metodológicos bilingües AICLE (aprendizaje integrado de contenido y lengua extranjera) en las clases de Educación Física y el tiempo de compromiso motor (TCM) en escolares dela Región de Murcia. Para ello, se ha estudiado las distintas categorías de tiempo en las clases de Educación Física, analizando una muestra aleatoria de tercer curso de Primaria de 8 centros de la Región de Murcia. El análisis de los datos revelan diferencias significativas en el tiempo empleado en la tarea y en el tiempo de organización entre los centros bilingües y monolingües. Además se encuentran diferencias en el tiempo de compromiso motor, siendo significativas en el análisis multivariante (Anova) cuando se comparan con la titularidad del centro (público y privado-concertado). Estos datos revelan la necesidad de estudiar las consecuencias que está teniendo la introducción de una lengua extranjera en el área de Educación Física así como plantear soluciones reales para darle respuesta.Abstract: The aim of this research paper is to analyze the relationship between the introduction of bilingual methodological CLIL (Content and Language Integrated Learning) approaches in Physical Education (PE) lessons and engagement motor time (TCM) in primary students from Murcia. The different categories of time in PE classes were studied by analyzing a random sample of third grade students from eight schools in the Region of Murcia. The analysis of the data showed significant differences in the time spent on the task and the time of organization between monolingual and bilingual schools. In addition, differences in TCM were found, which were significant in multivariate analysis (Anova) when TCM is compared with the school ownership (state and private school). These data reveal the need to study the consequences of introducing a foreign language in Physical Education subject and to propose real solutions to give response to those consequences.

MUSCLE RECRUITMENT PATTERNS AND CONSISTENCY, AND THEIR CORRELATION WITH MOTOR TIME DURING A KARATE FRONT KICK

Adequate muscle recruitment patterns and their consistency are essential to achieve effective posture and force exertion during a karate front kick. The purpose of this study was to evaluate the reaction time (RT), motor time (MT) and total response time (TRT), as well as their correlation during a front kick, and to investigate the muscle recruitment patterns and their consistency during motor time. Fourteen professional karate athletes (age: 23.7 ± 2.6 years; height: 174.6 ± 7.1 cm; mass: 72.8 ± 10.7 kg) participated in the current study. Each subject was instructed to pose in combat stance first and then to use their right leg to kick at an instrumented kicking target as soon as they saw the start signal. Surface electromyograms (EMG) were recorded from 16 muscles. Start and stop signals from the instrumented target were also recorded synchronously to obtain the TRT. Significant correlation between MT and TRT indicated that MT was a primary determinant for the TRT of the kick. The muscle recruitment synergies during karate front kicks were identified. When performing a front kick, the athletes initiated the postural adjustments of the supporting leg prior to the onset of the voluntary kick. A successful motion of the karate front kick was dependent not only on the kicking leg, but also on the supporting leg. Tibialis anterior, biceps femoris and gluteus maximus of the supporting leg were the primary muscles providing stabilization, while the ankle and knee flexors, and tensor fasciae latae of the kicking leg were dominant muscles for the kicking movement. These results provide important information on the patterns and the consistencies of the muscle recruitment for coaching a karate front kick, which should be helpful for a better understanding of the motor control strategies of a karate front kick and for developing a suitable training protocol.

Target-to-Distractor Ratio Effects on Decision Time in the Orderly Array Shape Cancellation Task

The cancellation task is a paper-and-pencil test commonly used to assess attention or planning. This study investigated whether the decision time performance on the task was influenced by the number of targets and distractors. This study reduced the demand of planning and used an index of the decision time, an estimate of the time taken to decide whether to mark a stimulus. Forty healthy adults ( M age = 21.3 yr., SD = 1.5) performed five cancellation tasks. Four tasks were conducted with instructions to mark a detected target. The target-to-distractor ratio varied from 35/15,40/10,45/5, and 50/0, and one task with instructions to mark all stimuli (50/0), to measure the motor time to mark targets. One-way analysis of variance indicated statistically significant differences between conditions. There was a linear relationship between decision time and target-to-distractor ratio; the decision time increased as the proportion of distractors increased. The results suggested the decision time reflects the frequency of switches between responses to targets and distractors or attention modulation of processing to targets and distractors.

Asymmetry of Complex Reaction Time in Female Épée Fencers of Different Sports Classes

Introduction. The issue of asymmetry is becoming more and more widespread, causing considerable difficulties for sportspersons. The aim of this study was to assess dynamic asymmetry of complex reaction time in female épée fencers from different sports classes. Material and methods. Study participants comprised 45 female fencers divided into 3 groups. The RT-S5 test of the Vienna Test System was used to record reaction time and motor time in response to visual and audiovisual stimuli. Conclusions. The study found differences in complex reaction time between fencers of different sports classes. Champion-class fencers showed a very high dynamic asymmetry. Considerable differences in complex reaction time were found depending on the type of stimulus involved.