There are four generally accepted boxing styles that are used to define fighters. These are the swarmer, out-boxer, slugger, and boxer-puncher. Many boxers do not always fit into these categories, and it's not uncommon for a fighter to change their style over a period of time.
Four Primary Boxing Styles
Combinations of styles
All fighters have primary skills with which they feel most comfortable, but truly elite fighters are often able to incorporate auxiliary styles when presented with a particular challenge. This usually results in a hybrid style that seeks to offset disadvantages and maximize strengths.For example, an out-fighter will sometimes plant his feet and counter punch, or an in-fighter may have the power of a brawler.</p>
There is a generally accepted rule of thumb about the success each of these boxing styles has against the others. In general, an in-fighter has an advantage over an out-fighter, an out-fighter has an advantage over a brawler, and a brawler has an advantage over an in-fighter; these form a cycle with each style being stronger relative to one, and weaker relative to another, with none dominating, as in rock-paper-scissors. Naturally, many other factors, such as the skill level and training of the combatants, determine the outcome of a fight, but the widely held belief in this relationship among the styles is embodied in the cliché amongst boxing fans and writers that "styles make fights."
Brawlers tend to overcome swarmers or in-fighters because, in trying to get close to the slugger, the in-fighter will invariably have to walk straight into the guns of the much harder-hitting brawler, so, unless the former has a very good chin and the latter's stamina is poor, the brawler's superior power will carry the day. A famous example of this type of match-up advantage would be George Foreman's knockout victory over Joe Frazier in their original bout "The Sunshine Showdown".
Although in-fighters struggle against heavy sluggers, they typically enjoy more success against out-fighters or boxers. Out-fighters prefer a slower fight, with some distance between themselves and the opponent. The in-fighter tries to close that gap and unleash furious flurries. On the inside, the out-fighter loses a lot of his combat effectiveness, because he cannot throw the hard punches. The in-fighter is generally successful in this case, due to his intensity in advancing on his opponent and his good agility, which makes him difficult to evade. For example, the swarming Joe Frazier, though easily dominated by the slugger George Foreman, was able to create many more problems for the boxer Muhammad Ali in their three fights. Joe Louis, after retirement, admitted that he hated being crowded, and that swarmers like untied/undefeated champ Rocky Marciano would have caused him style problems even in his prime.
The boxer or out-fighter tends to be most successful against a brawler, whose slow speed (both hand and foot) and poor technique makes him an easy target to hit for the faster out-fighter. The out-fighter's main concern is to stay alert, as the brawler only needs to land one good punch to finish the fight. If the out-fighter can avoid those power punches, he can often wear the brawler down with fast jabs, tiring him out. If he is successful enough, he may even apply extra pressure in the later rounds in an attempt to achieve a knockout. Most classic boxers, such as Muhammad Ali, enjoyed their best successes against sluggers.