Martial arts have become increasingly popular in the West, where they are practiced for self-defense, mental discipline, harmony of body and mind, physical fitness, and sport. It is estimated that 2–10 million Americans actively train. The literature pertaining to traditional martial arts training indicates that black belts do not conform to the violent, aggressive stereotypes portrayed in popular martial arts movies. Moreover, martial arts principles, philosophy, and techniques have been successfully applied in a clinical setting to improve the physical well-being of the physically challenged and to modify the attitudes, emotions, and behavior of troubled adults and teenagers. Mental imagery shows promise as a psychological intervention strategy to enhance Karate performance of beginning students. The techniques of Karate are well grounded in physics, and the velocities and tremendous forces and energies generated by skilled practitioners have been quantitated. Studies have also examined the health-related and skill-related fitness of martial artists.