Martial arts are codified combat systems used for self-defense and include striking arts like karate which uses punches, kicks, and open-handed techniques, grappling arts like judo, full-contact kickboxing, and capoeira which combines martial arts, music and dance with acrobatic sparring. The document discusses the history and techniques of different martial arts and concludes that they are good for self-defense and health, asking if the reader has ever practiced or wants to practice martial arts.