Yoga teaches breathing awareness, self-regulation, conscious relaxation of muscles, and an internal awareness; skills common to many stress reduction programs. The study showed that yoga was, from the first class, a good method of reducing stress, so it would seem that there is no need for long practice of the skills before seeing the benefits. Since fencing satisfied none of the main criteria for stress reduction, the researchers did not expect it to influence mood and, in fact, few effects were seen, but students did show more vigor after their classes. Taekwondo classes that stress abdominal breathing and are noncompetitive, predictable, and rhythmical tend to reduce stress.
Richman and Rehberg, in a 1986 study, The Development of Self-esteem Through the Martial Arts, in International Journal of Sports Psychology, examined self-esteem before a sport karate tournament and the effect of winning a trophy during the competition. Students were grouped into beginner, intermediate, advanced, and expert groups. Beginners showed lower self-esteem than the other three groups while the other three were not significantly different from each other. When compared to members within their own school, self-esteem was related to self-perception, but not to self-ratings of sportsmanship or discipline. The authors concluded that 1-2 months of karate training was enough to raise self-esteem. Measures on the groups that trained for longer periods showed no changes in this measure. The self-perception of ability was related to self-esteem. Self-perception of physical condition and self-discipline were also important to self-esteem, and self-esteem predicted performance. The study found that Karate students have a realistic appreciation of their own abilities, and that possession of these abilities is related to their self-esteem. Training in Karate does not seem to result in unrealistic appraisals of one's abilities.