The Contextual Interference Effect in Learning Parameters of the Generalized Motor Program.

Four experiments examined the generalizability of the contextual interference (CI) effect. In all experiments, to examine the locus of the CI effect measures assessing generalized motor program (GMP) learning and parameter learning were used in addition to a measure of general performance. In the first two experiments, variations of a timing tapping task, which were controlled by either different GMPs (Experiment 1) or the same GMP (Experiment 2), were learned under either blocked (low CI) or serial (high CI) practice. The CI effect was found for the general performance measure regardless of the task characteristics, contrary to Magill and Hall\u27s (1990) hypothesis that tasks controlled by the same GMP do not create the CI effect. The dissociated measures of GMP learning and parameter learning showed that parameter learning was enhanced by high CI practice in both experiments and there was a tendency that GMP learning was also enhanced by high CI practice in Experiment 1. To extend the findings with timing characteristics, Experiment 3 involved task variations requiring modifications of the overall force parameter of the same GMP. Consistent with the results of Experiment 2, the results showed the CI effect for overall force parameter learning that was also reflected in the general performance. In Experiment 4, task variations requiring simultaneous modifications of both overall duration and overall force parameters of the same GMP were learned. The results showed the CI effects for both types of parameter learning, which were reflected in the general performance. Different amounts of practice used in Experiments 3 and 4 did not influence the efficacy of the CI effect. Findings based on retention and transfer tests in Experiment 4 were compatible with each other. Thus, the CI effect was found regardless of the task characteristics, the number and types of parameters modified, the amount of practice, and types of learning tests. These results indicate that the CI effect is generalizable to more various motor learning situations than previously believed because any aspect of performance that changes from trial to trial during practice leads to better retention and transfer regardless of the amount of practice

THE FUNCTIONS OF SPIN ON SHOT TRAJECTORY IN TABLE TENNIS

The purpose of this study was to examine the function of spin on shot trajectory during flight in table tennis. Using film images of an actual match, we computed the 3D coordinates of a ball to analyze the shot trajectories. The theoretical spin-free (TSF) ball trajectories, obtained using a similar approach to Jinji and Sakurai (2006), were compared with the observed shot trajectories. For drive shots, the shot length in the TSF ball was significantly longer than in the observed shots. However, for push shots, among the 30 shots analyzed, 17 of the TSF balls traveled a shorter distance than the observed shots, though difference between them was found not to be significant. The work done by Magnus effect on the ball was estimated by the amount of deflection in vertical direction during flight

Interactive influence of task characteristics and amout of practice on the contextual interference effect in motor learning : A review

The contextual interference (CI) research related to the Magill and Hall (1990) hypothesis concerning task characteristics was reviewed to reexamine the hypothesis. Through this process, describing the weaknesses of the hypothesis led to proposing a multiple factor approach to the generalizability of the CI effect. A modification to the Magill and Hall hypothesis was proposed considering the interaction between task characteristics and the amount of practice. The modified hypothesis holds that when task variations are controlled by different generalized motor programs (GMPs), the CI effect would be found in both early and later practice. In contrast, when task variations are controlled by the same GMP, the CI effect would be found only in later practice

The influence of monetary reward and punishment on psychological, physiological, behavioral, and performance aspects of a golf putting task

The primary purpose of the present study was to examine kinematic characteristics and force control during a golf-putting task under a pressure condition. The secondary purpose was to provide an exploratory investigation of the relationship between changes in behavior (kinematics and force control) and performance on the one hand, and psychological (attention and affect) and physiological (arousal level) changes on the other hand. Twenty male novices performed 150 acquisition trials, followed by 10 test trials during a pressure condition induced by performance-contingent distracters: a cash reward or punishment. A three-dimensional motion analysis revealed that, during the pressure test, angular displacements of rotational movements at the horizontal plane and movement time of the arms and club during the backswing and downswing phases all decreased, while acceleration of the elbows during the downswing phase increased. Mean performance indices in all participants' were unchanged in spite of the kinematic changes under the pressure condition. Multiple regression analyses indicated that the decrement in performance, as well as increased variability of movement time and speed, were more likely to increase when participants shifted their attention to movements. Furthermore, changes in heart rate and negative affect were related to both the increase in movement acceleration and a decrease in grip force. These findings suggest that performance and behavioral changes during golf-putting under pressure can be associated with attentional changes, along with the influences of physiological-emotional responses

Optimization of treatment strategy

The purpose of this study was to predict the survival time of patients with malignant glioma after radiotherapy with high accuracy by considering additional clinical factors and optimize the prescription dose and treatment duration for individual patient by using a machine learning model. A total of 35 patients with malignant glioma were included in this study. The candidate features included 12 clinical features and 192 dose–volume histogram (DVH) features. The appropriate input features and parameters of the support vector machine (SVM) were selected using the genetic algorithm based on Akaike’s information criterion, i.e. clinical, DVH, and both clinical and DVH features. The prediction accuracy of the SVM models was evaluated through a leave-one-out cross-validation test with residual error, which was defined as the absolute difference between the actual and predicted survival times after radiotherapy. Moreover, the influences of various values of prescription dose and treatment duration on the predicted survival time were evaluated. The prediction accuracy was significantly improved with the combined use of clinical and DVH features compared with the separate use of both features (P < 0.01, Wilcoxon signed rank test). Mean ± standard deviation of the leave-one-out cross-validation using the combined clinical and DVH features, only clinical features and only DVH features were 104.7 ± 96.5, 144.2 ± 126.1 and 204.5 ± 186.0 days, respectively. The prediction accuracy could be improved with the combination of clinical and DVH features, and our results show the potential to optimize the treatment strategy for individual patients based on a machine learning model

石 川 啄 木 に お け る 〈 安 楽 〉

departmental bulletin pape

質量選別光解離分光法による、芳香族分子クラスターイオンのイオンコア構造と光誘起電荷ホッピングの研究

2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 2Cp0