Akifumi Kijima

University of Yamanashi · Graduate School of Education

We investigated whether the patterns of coordination that emerged during a three-participant (triadic) jumping task were defined by the symmetries of the (multi) agent-environment task space. Triads were instructed to jump around different geometrical arrangements of hoops. The symmetry of the hoop geometry was manipulated to create two symmetrical...

Competition in sports, unlike cooperation in everyday life, does not involve a single solution because individuals aim to behave unpredictably, thereby preventing others from predicting their actions. This study determined how individuals in court-based sports attempted to control others’ unpredictable behaviors, addressing the gap in previous stud...

Competition in sports, unlike cooperation in everyday life, does not involve a single solution because individuals aim to behave unpredictably, thereby preventing others from predicting their actions. This study determined how individuals in court-based sports attempted to control others’ unpredictable behaviors, addressing the gap in previous stud...

Competition in sports does not involve a single solution because individuals aim to behave unpredictably, thereby preventing others from predicting their actions. This study determined how individuals in court net sports tried to control others' unpredictable behavior, thereby addressing the gap of the lack of clarity about strategies employed by i...

Previous research has shown that experienced players in various sports can detect subtle differences in their opponents’ movements and anticipate the outcomes of the movements accurately and rapidly. In these methods, the researchers presented opponents’ movements, such as serving and striking, to their participants, and measured the precision of a...

The use of an immersive virtual reality system as a work space for sports and physical education can help maintain physical communication from separate places. In this study, we verified the possibility of constructing a movement synchrony system by reproducing the mathematical ordered pattern of “triadic jumping” in a virtual space. Three jumpers...

In real hockey or soccer games, scoring opportunities usually occur quite rarely, and thus, for most of the duration of a game, the ball is drifting between the two goals. This pass-chaining situation can be regarded as the stable state of the offense–defense interaction. In the current study, temporal and spatial structure of this dynamical state...

The development of an immersive virtual reality system, available as a work space for both sports and physical education, would be beneficial considering the current state of high-risk virus infection. In this study, we confirm this possibility by reproducing the mathematical ordered pattern of “triadic jumping” in a virtual space. Three jumpers we...

Complex human behavior, including interlimb and interpersonal coordination, has been studied from a dynamical system perspective. We review the applications of a dynamical system approach to a sporting activity, which includes continuous, discrete, and switching dynamics. Continuous dynamics identified switching between in-and anti-phase synchroniz...

Complex human behavior, including interlimb and interpersonal coordination, has been studied from a dynamical system perspective. We review the applications of a dynamical system approach to a sporting activity, which includes continuous, discrete, and switching dynamics. Continuous dynamics identified switching between in- and anti-phase synchroni...

In daily life and in many sports, people must adjust interpersonal distance between themselves and others based on task constraints and goals. For example, in martial arts such as boxing and kendo, players must adjust interpersonal distance before starting or defending strikes. However, it is not clear what players perceive and how players use this...

When two or more candle flames are fused by approaching them together, the resulting large flame often exhibits flickering, i.e., prolonged high-frequency oscillation in its size and luminance. In the present work, we investigate the collective behaviour of three-coupled candle flame oscillators in a triangular arrangement. The system showed four d...

The multiplayer dynamics of a football game is analyzed to unveil self-similarities in the time evolution of player and ball positioning. Temporal fluctuations in both the team-turf boundary and the ball location are uncovered to follow the rules of fractional Brownian motion with a Hurst exponent of H ∼ 0.7. The persistence time below which self-s...

The multiplayer dynamics of a football game is analyzed to unveil self-similarities in the time evolution of player and ball positioning. Temporal fluctuations in both the team-turf boundary and the ball location are uncovered to follow the rules of fractional Brownian motion with a Hurst exponent of H=0.7. The persistence time below which self-sim...

Participation in interpersonal competitions, such as fencing or Japanese martial arts, requires players to make instantaneous decisions and execute appropriate motor behaviors in response to various situations. Such actions can be understood as complex phenomena emerging from simple principles. We examined the intentional switching dynamics associa...

Intermittency on the return maps. Animated clip showing examples of the pattern of intermittencies on the return maps, which include the time series of and , velocities of step-toward and step-away of each player, and 2D movement from top of view, and approaching and diverging around the attractive fixed point and/or repellent fixed point exponenti...

Switching among several functions in one scene. Animated clip showing examples of the pattern of switching among several functions on the return maps, which include the time series of and , velocities of step-toward and step-away of each player, and 2D movement from top of view. (MOV)

Attractor on the return maps. Animated clip showing examples of the pattern of attractors on the return maps, which include the time series of and , velocities of step-toward and step-away of each player, and 2D movement from top of view, and approaching to the attractive fixed point asymptotically and rotationally. (MOV)

Repeller on the return maps. Animated clip showing examples of the pattern of repellers on the return maps, which include the time series of and , velocities of step-toward and step-away of each player, and 2D movement from top of view, and diverging from the repellent fixed point asymptotically and rotationally. (MOV)

Histograms of each match and its return map. A and C, Examples of histograms of well-fitted peaks of each match. The thresholds were determined from the minimum frequency value of each match. The higher values of the peaks were regarded as “farthest apart” high-velocity states, denoted as “F”; the lower values of the peaks were regarded as “nearest...

Examples of return maps and switching function from a series of points in a scene. Red lines show attractors, and blue lines show repellers. Cyan lines show intermittency in all panels. A Nine functions, B seven functions, and C-H five functions were switched sequentially. (EPS)

In many competitive sports, players need to quickly and continuously execute movements that co-adapt to various movements executed by their opponents and physical objects. In a martial art such as kendo, players must be able to skillfully change interpersonal distance in order to win. However, very little information about the task and expertise pr...

In competitive sport game behavior, certain interpersonal patterns of movement coordination evolve even though each individual player only intends to exert their own strategy to win. To investigate this interpersonal pattern formation process, we asked pairs of naïve participants to engage in a play-tag game in which they had to remove a tag fasten...

Detail of role detection procedure. A: An example of time series of and observed in a late-longest trial performed by pair # 5. B: calculated from the data presented in Figure S1 A. Vertical dotted line indicates timings of role transition (or recursion) indicated by zero-crossing point of .C: and it's zero-crossing points in 15–20s region in Figur...

Heart rates and HRR before and during each trial. (EPS)

A supplementary measure of strike-movement time. Players’ striking movements in matches were measured to identify players’ physical constraints and the task properties of kendo. The strike movements were measured during the tobikomi-men (lunge-and-strike) movement. Players frequently attempted to strike an opponent’s head (men) from an interpersona...

Descriptive numerical information regarding each of #1 to #5 pair's performance. N. of Trials: Number of trial repetition. Dur.: Duration of a trial (in seconds). N. of TP.: Numbers of thrusts (and parries) in each trial. Thrusts were estimated from numbers of peaks observed in a time series of inter-participant distance (examples of data were show...

Effectiveness of Hilbert transform on current data. (PDF)

State transition diagram and role transition intervals for late-longest trial performed by the 5 pairs. Upper: State transition diagram for late-longest trial by individual pair. Lower: Frequency (in %) of time interval for role transition observed in late-longest trial performed by individual pair. (EPS)

Details of participants. (EPS)

Comment about the potential effect of inter-game interview on game behavior. (PDF)

Movie showing an example of play-tag. (MOV)

Segmentation procedure according to two players' distance (). (PDF)

In order to pass through apertures safely and efficiently, individuals must perceive the width of the aperture relative to (1) the width of the person-plus-object system and to (2) their (anticipated) movement speed. The present study investigated whether athletes who have extensive experience playing sports that require running through narrow spac...