In college, some of us went through a brief fad of putting on the gloves and sparring out on the balcony of Burton Dorm at Faulkner University. It was fun until your opponent and erstwhile friend landed a punch on your schnoz. Then, finesse and skill gave way to wild flailing. Fortunately, it was only a fad.
Boxing was one of the ancient Greek games. According to the Perseus Project, "Ancient boxing had fewer rules than the modern sport. Boxers fought without rounds until one man was knocked out, or admitted he had been beaten. Unlike the modern sport, there was no rule against hitting an opponent when he was down...Instead of gloves, ancient boxers wrapped leather thongs (himantes) around their hands and wrists which left their fingers free" (www.perseus.tufts.edu). There are ancient Greek drawings in the University of Pennsylvania Museum of Archaeology and Anthropology, showing these ancient athletes in action. The boxers, according to a scornful Plato, are "the folk with the battered ears" (ibid.).
They were prominent enough figures that Paul referenced them by inspiration in 1 Corinthians 9:24-27, alluding to these games and their competitors. He illustrated his own self-discipline as a Christian and preacher by talking about the superior nature of Christianity to such earthly things, from the reward given to the victor to what was at stake by failing to win. In verse 27, he says, "I box in such a way, as not beating the air." Maybe Paul had seen a boxer landing facial and body blows, hitting his opponent when on the ground, and delivering leather to nose or ears. Maybe he had heard the distinct sound of flesh being pounded in such a match. Paul in essence says, "I deliver these blows to my body, keeping it in subjection to the Lord's will." I cannot let my flesh win or lose to that dangerous opponent. In the same way, the Lord calls on us to fight this tenacious opponent called the fleshly self. If we lose, Paul says, the penalty could not be more severe or the shame more great.