Martial arts are codified combat systems used for self-defense and include striking arts like karate which uses punches and kicks, judo which is a grappling art, full-contact kickboxing, and capoeira which combines martial arts, music and dance in an acrobatic style. The document discusses the history and techniques of different martial arts and concludes that they provide beneficial exercise and self-defense skills while also asking the reader questions about their experience with these combat sports.