Stochastic dynamics hidden in Japanese martial arts

Abstract

Martial arts like judo or Japanese fencing (kendo) are considered typical interpersonal competitions of human motor behavior. This kind of competition requires one to attack an opponent while simultaneously avoiding the opponent's attack. To quantify the practical behavior of interpersonal distance (IPD) between two players from the viewpoint of a dynamical system, we observed players' movements in kendo matches by a motion capturing system. The participants were twelve college athletes whose team had won in All Japan championships. The time series of the IPD from the coordination phase to the attacking phase was extracted, and 419 scenes were analyzed. A return map analysis was applied to the data using peak detections. We could describe the interpersonal competition during a kendo match in terms of state transitions, as in a Markov process. This suggests that complex human movements in interpersonal competition are self-organized by a simple principle. Martial arts like judo or Japanese fencing (kendo) are considered typical interpersonal competitions of human motor behavior. This kind of competition requires one to attack an opponent while simultaneously avoiding the opponent's attack. To quantify the practical behavior of interpersonal distance (IPD) between two players from the viewpoint of a dynamical system, we observed players' movements in kendo matches by a motion capturing system. The participants were twelve college athletes whose team had won in All Japan championships. The time series of the IPD from the coordination phase to the attacking phase was extracted, and 419 scenes were analyzed. A return map analysis was applied to the data using peak detections. We could describe the interpersonal competition during a kendo match in terms of state transitions, as in a Markov process. This suggests that complex human movements in interpersonal competition are self-organized by a simple principle.


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