This paper analyses Jiu Jitsu as one of the most famous martial arts, which had its beginnings and foundation in Japan and then spread all over the world. There are many forms of sports jiu jitsu, the original and most popular was judo, now an Olympic sport. One of the most common are mixed style competitions, where competitors use a variety of strikes, throws and holds to score points. Then the basic characteristics of jiu jitsu are covered. In jiu-jitsu, practitioners practice using many potentially fatal or crippling moves, such as joint throws. Today, there are many highly modernized styles of jiu-jitsu that stick to their Japanese roots to varying degrees. The continuation of the work brings information about the most basic rules of fighting, training methods and types of belts in jiu jitsu. Each of the combat sports requires the competitor to perform different technical movements and skills, induces a specific metabolic response during the actual competition and requires the possession of different physiological characteristics. On this topic, fitness preparation in general in martial arts, and then fitness preparation specifically in jiu jitsu, are discussed. Strength and conditioning are key to preventing injury and keeping an athlete's body in top shape. The theoretical background on fitness preparation in jiu jitsu includes information on gaining muscle mass, aerobic and anaerobic training, sports performance and motor skills and maintaining fitness. When it comes to fitness, the most important thing is adapting to training, recovering between training and/or competition, preventing fatigue and overtraining, and adapting nutrition to the sport itself. It is concluded that Jiu Jitsu is a physically demanding sport that puts significant stress on the joints, muscles and tendons, but susceptibility to injury and fatigue can be prevented by engaging in an intensive conditioning program that includes several of the previously mentioned items.