The fights are never frowned upon unless you are on a ring , in this case there will be many bumps and everything is for the sport and spectacle. These fights melee can be of many types, the most common are usually Boxing although other of martial arts and even wrestling quadrilaterals have their place in the world.
But before fighting you become a real fighter, for that you have to train in the gym and fight with other aspirants to improve your skills. Each day of training will mean the difference between victory and defeat in the ring. Each type of martial art has its specific training and if you want to master them all, you'll have to train a lot since hitting a punching bag to fight real ninjas.
You can learn the dark arts of the ninja to beat your enemies quickly, you can even learn to read their movements. This is very important because if you know an opponent will throw a punch or kick, you dodge really fast.