Ethnology is the science that studies the world's economies, the ways of life of human being, religious beliefs, the systems of organization and everything that encompasses the social and cultural world, with this knowledge comparisons can be made between differents ethnic groups and that way we can see the different facets or transformations of a social phenomenon. An example to understand better what “ethnology” is. Studies of an ethnic group “A” are made where it is understood that this group has monotheistic religious practices (belief in a single god) with specific religious rituals, while on the other side of the globe there is a "B" culture that has a religious belief that is expressed in a polytheistic way (belief in several gods). This is an ethnological analysis about religion, the analysis or ethnological research is more extensive and detailed, we are only approaching to have a better understanding of science.
Martial arts are methods of physical and mental defense linked to the ethical code or philosophy of life, where religion also intervenes. While martial arts are a social phenomenon that are built within a cultural world where they play a role for society whether be in some cases for entertainment and sporting purpose (such as the Greco-Roman wrestling in the first Olympics in Greece ) or for the training of warriors with religious purpose, (such as Kung fu and its origins with the monk Bodhidarma in India, being the principle of this martial art, "harnessing the strength of the opposite", the core of the martial arts in Asia). Currently, a large part of martial arts are recreational practices for their great physical, spiritual and sports benefits in which the competitive world standsout.
Now there is a question, what does a bunch of people wrestling and fighting with a filosophical and moral purpose have to do with ethnology? with a philosophical or moral sense with ethnology? Well, easy. The martial arts is a social phenomenon that is found in various parts of the world.
It is highly linked with other social agents such as religion (for example the relationship of Kung fu with Taoism), economics (betting on contests very seen in boxing), forms of expressed ideologies. Based a little more on the internal martial arts we can analyze the differences and similarities in the techniques used in the martial arts of the world and their relationships, relationships in fighting styles, martial loans and adaptation (for example the case of jiu jitsu Brazilian with judo: Brazilian jiu-jitsu was developed based on judo as the main base, modifying its form of combat taking a large loan of techniques and developing them in a different way). For all this and much more, martial arts are a great source of research for the social sciences.