Aggression has many faces in sport. For this reason, it is a complex but fascinating field for studying the nature of aggression. All athletes have to control and channel aggression constructively into skill in their sport in order to sustain optimal performance. The purpose of this research was to study aggression in sport and determine whether aggressive energies can constructively be expressed in the rules of the game and channelled into a powerful and inspiring performance by the athlete. In sport, any type of aggression can transmute into a destructive force that can debilitate and nullify performance. Through this study, the researcher wanted to determine if the participation in Martial Arts can reduce aggression and whether progression in belt rank (beginner, intermediate and advanced) in Martial Arts could cause a gradual decrease in the aggressive behaviour of young adolescents. The researcher also wanted to determine if participation in Martial Arts, other than other types of sports activities (for example, hockey) and those 16 participants absent from any sporting activity, may serve as a deterrent to aggressiveness. A secondary aim was to determine if Martial Arts could be used as a coping strategy for young adolescents to improve their overall mental wellbeing. The core focus of this study is to determine if the participation in Martial Arts (specifically Tae Kwon Do) can reduce aggressive tendencies in young adolescents. The researcher chose Tae Kwon Do from the various Martial Arts styles, because Tae Kwon Do has a very broad combination of traditional components or elements of what any Martial Arts program consist of. It also consists of elements that are incorporated within the program that may have the desired outcome on a participant taking part in such a training program. In Martial Arts, the emphasis is on physical fitness, self-confidence and training in mental control. Most combat activities are usually thought of as providing opportunities for the display of competence and masculinity, the development of self-confidence and a release of tension with the sublimation of aggressive impulses. The term “Martial Arts” will be used throughout this study. The researcher decided on a survey method to carry out this study. Standardised questionnaires were used to determine whether progression in belt rank (beginner, intermediate and advanced) in Martial Arts (group1) could cause a gradual decrease in aggressive behaviour among young adolescents. The results of the analysis of differences between the different levels of Martial Arts showed no statistically significant differences between the levels on all the aggression sub-scales. The personal growth scores, obtained from the responses to the psychological wellbeing questionnaire, were significantly lower for the beginner group than for the other two groups (intermediate and advanced). The results on the psychological wellbeing sub-scales indicated that the personal growth and self-acceptance scores of the Martial Arts group were significantly higher than those of the other two groups (hockey and non-participation). The group that did not participated in any sporting activity, had the lowest scores. Also to be determined was whether Martial Arts could be used as a coping strategy to improve the overall mental health of these adolescents. Copyright / Dissertation (MA)--University of Pretoria, 2009. / Biokinetics, Sport and Leisure Sciences / unrestricted