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

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

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

Relationship between ATE and probability.

<p>Relationship between absolute temporal error (ATE) in response to decreased velocity condition and probability that biphasic EMG pattern will appear in response to this condition.</p

Schematic diagram of relationships between absolute temporal error (ATE) and electromyographic (EMG) characteristics.

<p>Relationships: +, positive, <i>p</i> < 0.05; ++, positive, <i>p</i> < 0.01; --, negative, <i>p</i> < 0.01; -, negative, <i>p</i> < 0.05.</p

Outline of elapsed time from moment that target started to move until impact in response to unchanged and decreased velocity.

<p>Data are shown as means and SD. Target start (■), Onset of EMG activation (●), time to peak EMG amplitude in response to unchanged condition and monophasic EMG pattern in decreased velocity condition (▲), time to peak EMG amplitude of first (△) and second (□) peaks in response to biphasic EMG pattern in decreased velocity condition, impact time (×).</p

Example of time course of EMG signals in vastus lateralis muscle of front leg.

<p>Monophasic and biphasic EMG activation of vastus lateralis muscle of front leg of one participant in response to unchanged and decreased velocity conditions, respectively. Target start time was 0 s.</p

Inter-subject correlations (r) between parameters (n = 11).

<p>ATE, absolute temporal error; U, unchanged condition; DV, decreased velocity; Latency, latency time from onset of EMG activation to time to peak; Max, Peak EMG amplitude; Onset, onset of EMG activation from target start; Prob, probability that biphasic EMG will appear in response to decreased velocity; TP, time to peak from target start.</p><p>*<i>p</i> < 0.05</p><p>^†<i>p</i> < 0.01.</p><p>Inter-subject correlations (r) between parameters (n = 11).</p