Inhibition of Ironic Errors and Facilitation of Overcompensation Errors Under Pressure: An Investigation Including Perceived Weakness.

The conflicting predictions of ironic process theory and the implicit overcompensation hypothesis have been presented as a framework to explain the characteristics of errors that occur when a certain behavior is prohibited. The former predicts that instructions prohibiting a particular behavior will increase the likelihood of an outcome that should be avoided (ironic error), whereas the latter predicts that the likelihood of an outcome opposite of that to be avoided (overcompensation error) will increase. We examined how these errors, which negatively affect performance, are influenced by pressure and perceived weakness. Participants performed a tennis-stroke task, aiming to hit a ball toward a target zone while avoiding a discouraged zone. The results indicate that pressure decreases the ironic errors but increases the overcompensation errors that occur when a particular behavior is discouraged, while an increase in perceived weakness induces random errors.

The Effect of Choice on Motor Learning for Learners With Different Levels of Intrinsic Motivation.

This study examines whether the positive effect of choice on motor learning in a dart-throwing task varies by intrinsic motivation. Participants were allocated to a highly motivated or less-motivated group based on measured task motivation and randomly to a Choice or No Choice group. In Experiment 1, participants in the Choice group chose their dart color. In Experiment 2, they chose when to observe a model demonstration. Results showed that the effect of choice on motor learning differed between highly and less-motivated participants in Experiment 1 (i.e., interaction between motivation and choice) but not Experiment 2 (i.e., main effects of motivation and choice). Specifically, motor learning was enhanced in less-motivated but not highly motivated participants when choosing dart color, while it was enhanced regardless of initial intrinsic motivation when choosing model-demonstration time. Therefore, external provision of choice in a motor-learning situation may not be equally effective across learners.

Why does the Quiet Eye improve aiming accuracy? Testing a motor preparation hypothesis with brain potential.

The purpose of the present study was to determine whether the Quiet Eye (QE) acquired over time is associated with motor preparation processes by using movement-related cortical potentials (MRCPs). Eighteen male, right-handed college students voluntarily participated in this study. Participants performed a dart throw while wearing an eye-tracking system and electrode cap to measure electroencephalogram waveforms (EEG). After performing the dart task, participants were randomly assigned to a Quiet Eye training group (QET) or control training group (CT). Six subjects were excluded due to incomplete electroencephalography (EEG) data. MRCPs were analysed separately within 4 QE categories: High performance score and Long fixation time (HL), High performance score and Short fixation time (HS), Low performance score and Long fixation time (LL), and Low performance score and Short fixation time (LS). Results revealed that although the QET group acquired QE characteristics, MRCPs did not differ between the two groups. Thus, a longer-term experimental design may be necessary to observe EEG changes. Furthermore, QE durations may relate to not only motor programming but also online control.

The inhibition of motor contagion induced by action observation.

In sports, success and failure are believed to be contagious. Yet it is unclear what might cause contagion. This study investigated whether motor contagion is associated with the active observation of the kinematic actions of others. In Experiment 1, six skilled hammer throwers threw a hammer after watching a video of a model throwing toward the left, center, or right. The video included two types of action kinematics which resulted in throw directions that were either easy or difficult to predict based on the model's kinematics. In Experiment 2, the athletes threw hammers after watching the same stimuli as Experiment 1, but while engaging in one of two types of focus (self-focus or non-self-focus) to determine whether motor contagion could be diminished. Results demonstrated that the direction of each participant's throw was more influenced by the videos that contained easy action kinematics, supporting a critical role for the meaningfulness of the link between an action and its outcome in producing motor contagion. Motion analysis revealed that motor contagion was not likely to be a result of the observer imitating the model's action kinematics. The contagion observed in Experiment 1 disappeared when participants engaged in self-focus. These results suggest that motor contagion is influenced by the predictability of an action outcome when observing an action, and that motor contagion can be inhibited through self-focus when observing.

Concurrent Imitative Movement During Action Observation Facilitates Accuracy of Outcome Prediction in Less-Skilled Performers.

Skilled athletes can predict the outcome of actions performed by others, based on the kinematic information inherent in others' actions, earlier and more accurately than less-skilled athletes. Activation of the motor cortex during action observation indicates motor simulation of other's actions in one's own motor system; this contributes to skilled outcome prediction. Thus, the present study investigated whether concurrent movements during action observation that affect motor simulation influence the accuracy of outcome prediction, namely, whether concurrent imitative movement and self-movement enhance and inhibit accuracy, respectively, based on skill level. Twelve male varsity basketball players (skilled group) and twelve male college students with no special training in basketball (less-skilled group) were required to predict the outcome of a basketball free throw by another player based on the action kinematics in the following four conditions: prediction without any action (observation), prediction with right-wrist volar flexion with maximum speed (incongruent-action), prediction with concurrent imitative movement during observation by right-wrist flexion as if imitating the model's action (imitative-motion), or prediction with concurrent self-movement by right-wrist flexion as if shooting by oneself (self-motion). The results showed that the skilled group had degraded accuracy of outcome prediction in the self-motion condition compared to the observation condition. In contrast, accuracy in the less-skilled group was facilitated in the imitative-motion condition compared to the observation condition. The findings suggest that, at least in less-skilled participants, the appropriate motor simulation that relates to skilled prediction can be virtually induced by concurrent imitative movement during the prediction task, even if they have less experience of free throws. This effect in imitative movement is likely to occur by producing identical motor commands with observed action, thereby enabling the prediction of sensory consequences and outcome accurately via a forward model. We propose that traditional perceptual training with concurrent imitative movement is likely to be an effective way to develop visual- and motor-based hybrid outcome predictions that produce superior inferences in skilled athletes.

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.

Potential of rapid adjustment of brief interceptive action using predicted information.

Interceptive actions, such as hitting a ball in baseball or tennis, feature a moving target whose parameters (i.e., velocity or trajectory) differ across trials. This means that players are required to make rapid trial-by-trial adjustments. The purpose of this study was to determine whether a brief interceptive action could be adjusted using predicted sensory consequence of movement (pSCM) information, even under severe time constraints where the participants could not adjust their movement using only visual feedback. Participants performed an interceptive action for targets with two different velocities with different occurrence probabilities (20%, 50%, and 80%). Prior to movement onset, we applied transcranial magnetic stimulation (TMS) to the supplementary motor area (SMA), as TMS of the SMA is known to disrupt pSCM activity. We hypothesized that if pSCM information were used to adjust the motor parameters of a brief interception, then TMS would significantly increase the constant temporal error (i.e., the difference between the sum of reaction time and movement time and the total target visible time) for a target velocity with a low probability (20%). This hypothesis is based on the previous findings that the pSCM plays an important role in the adjustment of relatively brief interception. We found that while interceptions that lasted about 250 ms after movement onset were unaffected, interceptions that lasted about 350 ms after movement onset could be influenced by TMS. However, TMS interfered with performance provided that the delivery of the pulse occurred 100 ms before movement onset. This finding suggests that pSCM information that is used for a rapid adjustment is generated only in that specific time interval.

Color perception is impaired in baseball batters while performing an interceptive action.

In order to test the theoretical idea that experts rely more on the dorsal stream than the ventral stream during interceptive action for the interception of a moving target, the present study investigates the perception of color (dominant in ventral processing) during interceptive action in fast-ball sports. Twelve college baseball players and 12 non-baseball players performed a coincident-timing task with target color changes (from white to red, blue, or white) at various time points (at 100, 200, or 300 ms before target arrival). In this task, participants swung a bat and/or pressed a button in response to the target's arrival at a prespecified location. Participants were then asked to state the final color of the target. Baseball players, but not non-baseball players, were significantly less proficient at identifying color changes during the bat-swing condition relative to the button-press condition, irrespective of the time points of color change. These results are consistent with the idea that baseball players rely more on the dorsal stream during bat swinging for the interception of a moving target than do novices.

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.

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

BACKGROUND: It 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. RESULTS: Contraction 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). CONCLUSIONS: This 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.

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.

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.

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.

Fast-ball sports experts depend on an inhibitory strategy to reprogram their movement timing.

The purpose of our study was to clarify whether an inhibitory strategy is used for reprogramming of movement timing by experts in fast-ball sports when they correct their movement timing due to unexpected environmental changes. We evaluated the influence of disruption of inhibitory function of the right inferior frontal gyrus (rIFG) on reprogramming of movement timing of experts and non-experts in fast-ball sports. 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 either increased or decreased in some trials. The task was performed either with or without transcranial magnetic stimulation (TMS), which was delivered to the region of the rIFG. Under velocity change conditions without TMS, the experts showed significantly smaller timing errors and a higher rate of reprogramming of movement timing than the non-experts. Moreover, TMS application during the task significantly diminished the expert group's performance, but not the control group, particularly in the condition where the target velocity decreases. These results suggest that experts use an inhibitory strategy for reprogramming of movement timing. In addition, the rIFG inhibitory function contributes to the superior movement correction of experts in fast-ball sports.

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 target's 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 practice with within-trials and inter-trials changes of target velocity in improving movement correction.

In the present study, the influences of two practice methods on movement correction during interceptive action was examined. Fourteen men practiced intercepting a moving virtual target. One group practiced on a target that changed velocity from 4 to 8 m/sec. during the trial (within-trials change group). The other group practiced under Slow and Fast conditions, in which the initial velocity (4 or 8 m/sec.) remained constant (inter-trials change group). After the practice, both groups showed similar decreases in temporal errors in interception of an acceleration target. However, the within-trials change group showed non-corrected movements, whereas the inter-trials change group showed corrective movements. Thus, the practice methods for within-trials and inter-trials change resulted in different corrective strategies to acceleration target.