The purpose of this study was to quantify human dexterity by examining the movement involved in switching between forehand and backhand strokes when a ball moved from side to the other during table tennis. The hitting movements of expert and novice table tennis players were observed when balls were repeatedly moving in the same direction (periodic input condition) and when they were moving in two different directions successively (switching input condition). From the viewpoint of the switching dynamical system (Gohara and Okuyama, 1999a), the repeated movement under the periodic input condition was treated as an attractor, and the switching movement between strokes under the switching input condition was treated as transition of attractors. The dexterity with which movement were completed was quantified in terms of the fractal dimension. The fractal dimension was calculated according to Poincaré maps depicting the trajectories of the midpoint and angular velocities at the shoulder. Data from experts and novices almost reflected transitions of the third-order sequence effect, and the fractal dimensions included non-integers, which indicate that these fractal transitions had fractal properties. However, the fractal dimension of experts was lower than that of novices. The two output patterns corresponding to the two input patterns overlapped more for novices than for experts. The results suggest that the dexterity shown in switching movements can be quantified in terms of the fractal dimension based on the switching dynamical system.
Effects of explicit and implicit perceptual training on pitch-type (fast or curved-ball) anticipation with probability information prior to pitching motion were investigated. Participants (n=30) were randomly assigned to an explicit or an implicit instruction group, or a control group. They were administered 30 pretest trials, 60 perceptual training trials and 30 immediate retention test trials on the first day, 30 delayed retention test trials, 120 perceptual training trials and 30 immediate retention test trials on the second day, and just 30 delayed retention test trials on the third day. The explicit instruction group was instructed that they would be presented with anticipatory cues, whereas the implicit instruction group was instructed to react intuitively. The control group performed only the pretest and delayed test trials. During the pretest and delayed retention test trials, information on the probability of pitch-type was presented as a percentage, either 50% (chance level), 60%, or 80%, for one second at the start of a movie depicting the pitcher's motion. Results indicated that the level of awareness of anticipatory cues in the explicit instruction group was higher than in the implicit instruction and control groups, indicating that the instruction to react intuitively inhibited the awareness of anticipatory cues. The level of awareness of preceding information about pitch-type probabilities in the 80% condition was higher than in the 60% condition, indicating that the experimental manipulation of preceding information was effective. Anticipatory skill of the explicit instruction group improved after 60 perceptual training trials, whereas improvement of the implicit instruction group was marginally significant after 180 trials. It is concluded that explicit instructions result in faster learning during the perceptual training of novice baseball players.
This study primarily examines the usefulness of and the gender differences in the Health Action Process Approach (HAPA) to physical activity (PA) among Japanese university students. A total of 1,019 students (age=18-23 years, M=18.73 years, SD=0.64) participated in a selfadministered cross-sectional survey. All participants completed a questionnaire composed of sociodemographic variables (e.g., gender, age), risk perception, outcome expectancy, self-efficacy, behavioral intention, planning, and PA. Data were analyzed using structural and multi-group structural equation analyses. The results indicated that the HAPA model provided a good fit to the data and explained 31% of the variance in PA among Japanese university students. However, the HAPA also revealed several significant gender differences in the standardized path coefficients. These results suggest that the HAPA is a valid model for predicting PA among Japanese university students; however, gender differences in the HAPA should be considered when designing PA interventions.
The purpose of this study was (a) to examine how post-injury psychological states (competitive motivation, anxiety, impatience, isolation, disappointment, depression, and exhaustion) change in comparison with pre-injury states, and (b) to clarify the change of support provider and support content sought by injured athletes during the three phases of recovery prior to returning to competition. A population of 457 university athletes completed a questionnaire on their post-injury psychological state, the change of social support sought post-injury, and beneficial social support during rehabilitation. Results revealed that injured athletes experienced decreased competitive motivation and increased anxiety, impatience, isolation, disappointment, depression, and exhaustion. Results suggested that injured athletes sought support from “teammate", “student trainer", and “coach" before returning to competition and from “teammate" and “student trainer" during rehabilitation. Regarding support content, “technical advice" and “listening" consistently scored high, and “comforting", “material assistance", and “practical assistance", factors which may influence the state of recovery, decreased as injury improved. Finally, “technical advice" and “evaluation" which may influence post-recovery competitive activity increased as full recovery drew closer.
Effect of self-talk on motor performance was investigated. High school and junior high school students (N=24) participated in the study. They performed 400 meter timing trials each week for two weeks, such that first week was the baseline trial, and second week was the intervention trial. After the first trial, participants were assigned to one of two groups based on their swimming times: self-talk group (positive self-statements) or control group (thought suppression). In each of two trials, the participants were instructed to swim as easily as possible. After completing each trial, they requested to fill out the questionnaire that asked about their thoughts and perceived exertion rate while swimming, as well as fatigue, anxiety, and depression after swimming. Results indicated no change in the perceived rating of exertion and fatigue among the groups between the two trials. However, the group assigned to self-talk swam significantly faster in the intervention, compared to the baseline trial. Moreover, depression score in the self-talk group decreased significantly after the intervention, in comparison to the baseline. These results show that positive self-statements influence mood and the emotional state, in addition to the physical state and its cognition. The findings of this study suggest the usefulness of using self-talk by participants who aim to improve movements and enhance their performance.
This study sought to assess orientation to ideal self in an exercise and sports setting by developing the Ideal Self Orientation Scale for Exercise and Sports (ISOSES). In Stage 1 to develop the scale, participants were 170 university students. Principal component analysis revealed 8 items as single principal components, and the scale showed the reliability and validity. Furthermore, a t-test revealed no significant gender difference in scale scores. Participants in Stage 2 were 170 university students. The ideal self for exercise and sports setting was investigated using the KJ method, and results revealed that many students identify athletes with high performance, mental toughness, and sociality as their ideal self. In Stage 3, participants were 167 university students. Logistic regression analysis was performed to examine the influence of the orientation to ideal self on participation in exercise and sports setting. ISOSES scores revealed a significant influence on participation in exercise and sports setting. The present findings suggest that orientation to ideal self promotes exercise and sports participation.
April 03, 2017 There had been a system trouble from April 1, 2017, 13:24 to April 2, 2017, 16:07(JST) (April 1, 2017, 04:24 to April 2, 2017, 07:07(UTC)) .The service has been back to normal.We apologize for any inconvenience this may cause you.
May 18, 2016 We have released “J-STAGE BETA site”.
May 01, 2015 Please note the "spoofing mail" that pretends to be J-STAGE.