After 112 years of amateur competition, the Olympics are welcoming professional boxers.

All three of them.

The International Boxing Association's high-profile plan to entice prominent pros to Rio de Janeiro didn't work, leaving the sport without the star-studded tournament many apparently wanted.

Only a trio of traditional pros will compete for gold medals, and only hardcore boxing fans have ever heard of them: Cameroon's Hassan N'Dam, Thailand's Amnat Ruenroeng and Italy's Carmine Tommasone.

The Rio tournament will be more notable for what the men aren't wearing. AIBA has removed headguards from male Olympic fighters for the first time since 1980.

The biggest stars again could be the women, who are back for their second Olympics after providing the best moments in London.

Here are some more things to know when the 286-person tournament begins Aug. 6:


All three gold medal winners from the inaugural women's tournament in London are back to attempt to defend their titles. Britain's Nicola Adams, Ireland's Katie Taylor and American middleweight Claressa Shields all stuck with their sport, which has grown rapidly in prominence and quality over the past several years. In fact, only the dominant Shields is a strong favorite to repeat, given the improved competition at flyweight and lightweight.


AIBA announced its plan to remove Olympic headgear from the men three years ago, citing research claiming the bulky pads actually cause more concussions than they prevent. The quality of their science is considered dubious by many, but many fighters prefer to compete without the gear, and the sport is undeniably more telegenic when fans can see the fighters' faces.


The biggest problem with the headgear removal is likely to be cuts, which will develop more frequently without the facial protection. Qualifying tournaments have been filled with fighters unable to continue to their next bout after getting cut, and Olympic stars seem likely to meet the same fate.


AIBA has tried for years to become a player in international professional boxing under President Wu Ching-Kuo, but it has succeeded only in nations without an established pro boxing culture. The Olympic-style sport's growth in former Soviet republics will be obvious in Rio, where Kazakhstan (12 fighters), Azerbaijan (11), Uzbekistan (11) and Russia (11) will be well-represented along with the likes of Britain (12) and China (11). Cuba (10) has a fighter in every men's weight class, but still won't allow women to compete.


Another big change for Rio is the scoring system, which is no longer based on punch-counting. Fighters will be judged on the 10-point must system traditionally used in pro boxing, with the decision of each judge reduced to a single number. The final scores in the fights will be announced as 3-0 or 2-1. Unlike the headgear change, the move away from reviled punch-scoring has been greeted with broad approval. Still, it probably won't stop more than half of the losing fighters from claiming they were robbed, just as they do in every Olympic-style boxing tournament.


The U.S. team is the historic leader in total Olympic boxing medals and golds, but the Americans are sending just eight fighters to Rio after four men and one woman failed to secure spots through qualifying tournaments. The team might be small, but Shields and lightweight Mikaela Mayer are both medal contenders. The U.S. men didn't win a single medal in London, but touted bantamweight Shakur Stevenson has a great shot to end that drought in Rio.


You're not seeing things on the schedule: That's Muhammad Ali competing in Rio. The 20-year-old British flyweight with the conspicuous name is among the medal favorites after training in the same gym as Athens silver medalist Amir Khan.


Russian ex-world champion Albert Selimov is best known for losing his first fight in Beijing to Ukraine's Vasyl Lomachenko, the two-time gold medalist whose amateur legend truly began with that masterful performance. While Lomachenko reigns as a professional world champion eight years later, the 30-year-old Selimov is back at his second Olympics, fighting for Azerbaijan as a naturalized citizen. He is a medal favorite at lightweight.


Cuba, another traditional world power, could return to prominence in Rio after winning just two gold medals in London — a down Olympic cycle by its standards. Among its several strong medal contenders are London flyweight gold medalist Robeisy Ramirez, now fighting at bantamweight; three-time amateur light heavyweight world champion Julio Cesar La Cruz; and lightweight Lazaro Alvarez, a three-time world champion in two classes.