Examination of the effects of traditional and modern martial arts training on aggressiveness Nosanchuk & MacNeil (1989) have shown that the psychological benefits of martial arts are correlated with the length of participation.

This study addresses two issues associated with the relationship between martial arts training and aggressiveness. The first is a replication of two recent findings, that for students trained traditionally, length of training varies inversely with aggressiveness, whereas for students trained in a “modern” style, length of training and aggressiveness are related directly.

Second, we examine two competing explanations for the findings above. One is the training hypothesis, which holds that elements present in traditional approaches to martial arts but absent in modern approaches act to reduce aggression levels of students. These may include meditation, philosophy, emphasis on the kata (the forms of combat), etc. The alternate hypothesis, selection, holds instead that these findings are artifactual, a result of differential mortality in a setting characterized by high drop‐out rates.

Two categories of students were interviewed: “movers,” students who had trained in more than one school, and “quitters,” students who had terminated their training, for any reason. These students were compared with “stayers” from an earlier study. Our results are consistent with the opposite effects of traditional and modern martial arts training on aggressiveness. Further, the data generally support the training hypothesis as against selection.