Hiroki Nakamoto

Sport-Specific Decision-Making in a Go/Nogo Reaction Task: Difference among Nonathletes and Baseball and Basketball Players

The present study examined whether Go/Nogo reaction time (RT) is a relevant index of the sport expertise relating to sport-specific decision-making. 57 male university students, 20 basketball players, 24 baseball players, and 13 sedentary students as a control group, performed a Simple RT task and Go/NoGo RT task which had baseball specific stimulus-response relations. Participants in baseball and basketball differed further in having high, medium, and low experience in the sports. For comparisons across sports, the basketball and the baseball players had significantly shorter reaction times than the nonathletes in both tasks. In contrast, reaction times varied significantly across experience for the baseball players in the Go/NoGo RT task but not for basketball players. These results suggested that Go/NoGo RT could be used as an index of expertise for sport-specific decision-making, if stimulus-response relation in Go/NoGo RT task has a natural relation for a particular sport-domain.

Experts in Fast-Ball Sports Reduce Anticipation Timing Cost by Developing Inhibitory Control.

The present study was conducted to examine the relationship between expertise in movement correction and rate of movement reprogramming within limited time periods, and to clarify the specific cognitive processes regarding superior reprogramming ability in experts. Event-related potentials (ERPs) were recorded in baseball experts (n=7) and novices (n=7) while they completed a predictive task. The task was to manually press a button to coincide with the arrival of a moving target. The target moved at a constant velocity, and its velocity was suddenly decreased in some trials. Under changed velocity conditions, the baseball experts showed significantly smaller timing errors and a higher rate of timing reprogramming than the novices. Moreover, ERPs in baseball experts revealed faster central negative deflection and augmented frontal positive deflection at 200ms (N200) and 300ms (Pd300) after target deceleration, respectively. Following this, peak latency of the next positive component in the central region (P300b) was delayed. The negative deflection at 200ms, augmented frontal positive deflection, and late positive deflection at 300ms have been interpreted as reflecting stimulus detection, motor inhibition, and stimulus-response translation processes. Taken together, these findings suggest that the experts have developed movement reprogramming to avoid anticipation cost, and this is characterized by quick detection of target velocity change, stronger inhibition of the planned, incorrect response, and update of the stimulus-response relationship in the changed environment.

Kinesthetic aftereffects induced by a weighted tool on movement correction in baseball batting

We investigated the kinesthetic aftereffects of a weighted tool on interceptive performance. Eight college baseball players performed three warm-ups before the interceptive task: a normal warm-up, a recalibrated warm-up with a standard 850-g bat and a 1200-g weighted bat, and a weighted warm-up with a 1200-g bat. For the interceptive task, subjects were asked to swing the standard bat coincident with the arrival and position of a moving target. After the warm-ups with the weighted bat, participants felt that the bat was lighter and swung faster. When participants needed to correct their swings to the targets velocity change, larger timing errors were produced in the weighted than in the normal practice condition. These results indicate that warm-ups with a weighted tool create adverse effects for the movement (re)programming processes in interceptive action. This suggests that warm-ups with a weighted tool for an interceptive task affect the central nervous system and not the peripheral system.

Influence of Affordances in the Home Environment on Motor Development of Young Children in Japan

Previous research indicates that the home environment is a significant factor in early child development. The present study examined influence of the multidimensional home environment on young Japanese children’s motor development. A Japanese translation of the Affordances in the Home Environment for Motor Development-Self Report (AHEMD-SR) was used to assess home motor affordances in 262 families. Motor ability was assessed by parental report using the Enjoji Infant Analytic Developmental Test. We also asked parents to rate their own physical activity in terms of level and years of experience. As results, we found that the home environment in Japan was generally sufficient for children’s motor development and that children’s access to Fine Motor Toys (FMT) and Gross Motor Toys (GMT) had the strongest influence on their development. Analysis also indicated that AHEMD-SR scores were higher for children of parents who had some level of physical activity experience compared to children whose parents indicated no physical activity experience. Parents’ self-reported activity level was correlated with higher scores for the subscales FMT and GMT and for total AHEMD-SR score. These results indicate that both the physical and social-psychological environments (parental experience and views) of the home influenced children’s motor development.

Effect of Long-Term Body-Mass-Based Resistance Exercise on Cognitive Function in Elderly People:

The study examined the effect of a body-mass-based home exercise program on cognitive functioning among 170 male and female elderly people (52-81 years). This program comprised five kinds of resistance exercises that elderly people can perform at home without supervision or specialized equipment using only their body mass for resistance. Various cognitive tasks were used to assess cognitive functioning, including a simple reaction task, Go/No-Go reaction task, Stroop task, serial subtraction task, and coincident timing task. These tasks were performed before and after a 3-month body-mass-based home exercise program. Although there were no significant improvements in the simple reaction and coincident timing tasks, significant improvement was shown in the Go/No-Go reaction task and serial subtraction task. This study shows that even simple resistance exercise, using only body mass for resistance, may be an effective method for preventing age-related cognitive decline of inhibitory control and working memory among elderly people.

Muscle Activation Characteristics of the Front Leg During Baseball Swings with Timing Correction for Sudden Velocity Decrease

This study aimed to clarify the activation characteristics of the vastus lateralis muscle in the front leg during timing correction for a sudden decrease in the velocity of a target during baseball swings. Eleven male collegiate baseball players performed coincident timing tasks that comprised constant velocity of 8 m/s (unchanged) and a sudden decrease in velocity from 8 to 4 m/s (decreased velocity). Electromyography (EMG) revealed that the muscle activation was typically monophasic when responding unchanged conditions. The type of muscle activation during swings in response to decreased velocity condition was both monophasic and biphasic. When biphasic activation appeared in response to decreased velocity, the impact time and the time to peak EMG amplitude were significantly prolonged and the timing error was significantly smaller than that of monophasic activation. However, the EMG onset from the target start was consistent both monophasic and biphasic activation in response to conditions of decreased velocity. In addition, batters with small timing errors in response to decreased velocity were more likely to generate biphasic EMG activation. These findings indicated that timing correction for a sudden decrease in the velocity of an oncoming target is achieved by modifying the muscle activation characteristics of the vastus lateralis muscle of front leg from monophasic to biphasic to delay reaching peak muscle activation and thus prolong impact time. Therefore, the present findings suggests that the extent of timing errors in response to decreased velocity is influenced by the ability to correct muscle activation after its initiation rather than by delaying the initiation timing of muscle activation during baseball swings.

Effects of sport expertise on representational momentum during timing control

Sports involving fast visual perception require players to compensate for delays in neural processing of visual information. Memory for the final position of a moving object is distorted forward along its path of motion (i.e., “representational momentum,” RM). This cognitive extrapolation of visual perception might compensate for the neural delay in interacting appropriately with a moving object. The present study examined whether experienced batters cognitively extrapolate the location of a fast-moving object and whether this extrapolation is associated with coincident timing control. Nine expert and nine novice baseball players performed a prediction motion task in which a target moved from one end of a straight 400-cm track at a constant velocity. In half of the trials, vision was suddenly occluded when the target reached the 200-cm point (occlusion condition). Participants had to press a button concurrently with the target arrival at the end of the track and verbally report their subjective assessment of the first target-occluded position. Experts showed larger RM magnitude (cognitive extrapolation) than did novices in the occlusion condition. RM magnitude and timing errors were strongly correlated in the fast velocity condition in both experts and novices, whereas in the slow velocity condition, a significant correlation appeared only in experts. This suggests that experts can cognitively extrapolate the location of a moving object according to their anticipation and, as a result, potentially circumvent neural processing delays. This process might be used to control response timing when interacting with moving objects.

Warm-up with Weighted Bat and Adjustment of Upper Limb Muscle Activity in Bat Swinging under Movement Correction Conditions

The effects of weighted bat warm-up on adjustment of upper limb muscle activity were investigated during baseball bat swinging under dynamic conditions that require a spatial and temporal adjustment of the swinging to hit a moving target. Seven male college baseball players participated in this study. Using a batting simulator, the task was to swing the standard bat coincident with the arrival timing and position of a moving target after three warm-up swings using a standard or weighted bat. There was no significant effect of weighted bat warm-up on muscle activity before impact associated with temporal or spatial movement corrections. However, lower inhibition of the extensor carpi ulnaris muscle activity was observed in a velocity-changed condition in the weighted bat warm-up, as compared to a standard bat warm-up. It is suggested that weighted bat warm-up decreases the adjustment ability associated with inhibition of muscle activation under movement correction conditions.

Visuomotor process in movement correction: role of internal feedback loop.

This study examined the role of the internal feedback loop in movement correction during interceptive actions when what the performers expect to happen changes quickly. Eleven participants performed an interceptive task with a moving target under two conditions [Brief (8 m/s) or Long (4 m/s)]. We manipulated the probability of these target conditions to induce movement correction (20–80, 50–50, and 80–20%) and delivered transcranial magnetic stimulation before movement initiation to disrupt the prediction of the movement consequence in the supplementary motor area of the cerebral cortex. In the 20% probability condition, which requires movement correction, the transcranial magnetic stimulation pulse had a significant adverse effect on the temporal error in the Brief condition, but not in the Long condition. The present results indicate that the internal feedback loop is crucial for movement correction for relatively brief interceptions.

Muscle contraction and relaxation-response time in response to on or off status of visual stimulus

BackgroundIt is unclear whether response time is affected by a stimulus cue, such as a light turned on or off, or if there are differences in response to these cues during a muscle contraction task compared with a muscle relaxation task. The objective of this study was to assess the response time of a relaxation task, including the contraction portion of the task, to a stimulus of a light turned on or off. In addition, we investigated the effect of the pre-contraction level on the relaxation task.ResultsContraction response time was significantly shorter during the light-on status than during the light-off status (P <0.01), and relaxation response time in each maximum voluntary contraction was significantly longer during the light-on status than during the light-off status (P <0.01). The relaxation response time became longer in order of 25% to 75% maximum voluntary contraction regardless of light-on or -off status, and was significantly longer than the contraction response time (P <0.05-0.01).ConclusionsThis study found that as the contraction level increased, the relaxation response time became longer than the contraction response time regardless of light status. However, contraction response time or relaxation response time findings were opposite to this during the light-on status and light-off status: contraction response time became shorter in the light-on status than in the light-off status and relaxation response time became longer in the light-on status than in the light-off status. These results suggest that the length of each response time is affected by motor control in the higher order brain and involves specific processing in the visual system.