The theory of direct perception suggests that observers can accurately judge the mass of a box picked up by a lifter shown in a point-light display. However, accurate perceptual performance may be limited to specific circumstances. The purpose of the present study was to systematically examine the factors that determine perception of mass, including display type, lifting speed, response type, and lifter's strength. In contrast to previous research, a wider range of viewing manipulations of point-light display conditions was investigated. In Experiment 1, we first created a circumstance where observers could accurately judge lifts of five box masses performed by a lifter of average strength. In Experiments 2-5, we manipulated the spatial and temporal aspects of the lift, the judgement type, and lifter's strength, respectively. Results showed that mass judgement gets worse whenever the context deviates from ideal conditions, such as when only the lifted object was shown, when video play speed was changed, or when lifters of different strength performed the same task. In conclusion, observers' perception of kinetic properties is compromised whenever viewing conditions are not ideal.

The preparation and on-line control of short, rapid sequential aiming responses were studied in 3 experiments. Participants (N = 12 in Experiments 1 and 2, and 20 in Experiment 3) produced 3-segment responses (a) within self-initiation, simple reaction time (RT), and choice RT paradigms (Experiment 1); (b) without visual feedback under self-initiation conditions (Experiment 2); and (c) with and without visual feedback under simple RT conditions (Experiment 3). In all conditions in which participants initiated movement in response to an external imperative signal, the 2nd response segment was performed consistently slower than preceding and succeeding response segments. That pattern of segmental movement times was found whether or not visual feedback was available but was not evident when participants self-initiated their responses with or without visual feedback. The findings rule out the possibility that subjects' use of visual feedback is responsible for the slowing of the 2nd response segment under RT conditions and suggest that the programming of rapid sequential aiming responses can be distributed in pre- and postinitiation intervals.

After COVID-19, face-to-face learning was changed to online learning. However, very few effective online learning methods were available regarding physical education. Therefore, this study aimed to examine the modeling effects on learning ballet movement in the online system. We aimed to find effective modeling presentations based on objective information, expert assessments, and a kinematic approach. The study included 36 individuals who were divided into an expert modeling group, a self-modeling group, and controls. Participants performed 60 trials of Pas de basque in the acquisition phase and 10 trials without a demonstration video after 24 h. 10 min later, the reversed Pas de basque was conducted for the retention test. All groups showed improved performance after the acquisition phase, which indicated that the modeling presentation was effective despite adopting an online learning system. However, higher expert scores and more accurate joint movements were shown in the expert modeling group compared to the other groups. Therefore, expert modeling seems to be the most effective method for learning high-difficulty tasks with jumps and turns.

PURPOSE This study aimed to develop a positive psychological intervention program for a college ice hockey team and test its effects based on application to the team.METHODS The demands of 78 college ice hockey players were asked through open questionnaires. Collected results underwent integrated analysis to develop the desired program through the participants who were also observers of the team. The objectives of the program were established, and an appropriate program was developed based on the analyzed data, expert opinion, and precedent research. The developed program was applied to 26 players of a college ice hockey team to verify its effects. Tasks included writing experience reports and in-depth interviews. The Happiness Measures 1, Strength Knowledge, and Team Interaction Questionnaires were also administered. Collected qualitative data were categorized to follow inductive analysis procedures, while paired t-tests were performed for quantitative data using SPSS 25.0.RESULTS To improve the application of the program in real situations and maintain credibility and validity, the program was developed based on analyses of individual and team demands, methods of the participant as an observer, expert opinion, and other considerations. Statistically meaningful differences in positive psychological mind, happiness, recognition and utilization of strengths, team interactions, team cohesion, and so on were found using paired t-tests comparing data before and after the developed positive psychological intervention program.CONCLUSIONS Providing opportunities to recognize individual and team strengths and have valuable experiences for each player could enhance interactions between teammates and create a favorable team environment.

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