spresto, Aikido is one of the most effective of all of them in that it allows genuine defensive capability without the brute force that is required in Karate. It is more a defensive art than offensive. When Aikido for came to prominence back in the sixties it was when its main proponent, an elderly man, defeated six Karate black belts in open combat, a film (Documentary) that was show world wide. Like all martial arts, you have to stay in training, regular training, but it relies more on speed and reflex than on power. Part of that initial documentary showed the founder moving out of the way of bullets fired at him by US Police Officers pre-empted for the role. The reason for Police involvement is that it was being considered for use in Police work. He would move when he saw the muzzle flash and the board behind where he had been standing would be splintered by the bullet.