pulled from article by David Mayo at mlive.com
Muhammad Ali, 36
Before: 55-2, with losses only in his epic first bout with Joe Frazier and to Ken Norton when he fought through a broken jaw.
After: 1-3, split two fights with a youthful Leon Spinks, suffered his only stoppage loss against Larry Holmes, and was decisioned by Trevor Berbick.
Alexis Arguello, 30
Before: 70-5 and beat some of the sport’s biggest stars while cleaning out three weight divisions from featherweight to lightweight.
After: 7-3, including 5-3 in his final eight fights, although two of the losses were in his historic fights with Aaron Pryor, who handed him two of his three stoppage losses. Final loss came after a brief comeback at age 42.
Henry Armstrong, 28
Before: 110-13-8 and the only boxer in history to hold world championships in three weight divisions simultaneously, from featherweight (126 pounds) to welterweight (147).
After: 40-8-2, beginning with a loss to Fritzie Zivic in his last title fight, which was a rematch of another Armstrong loss in his previous fight.
Tony Canzoneri, 23
Before: 93-14-8, with championship reigns in two weight divisions after turning pro at age 16.
After: 44-10-2, including a loss to Wesley Ramey in Grand Rapids, after which he briefly regained the lightweight title. Career ended at age 30 with his only knockout loss, to Al “Bummy” Davis.
Julio Cesar Chavez, 31
Before: 87-0 and universal acclaim as pound-for-pound king.
After: 20-6-2, with a couple of decisions he might not have deserved, and four stoppage losses. Retired after four rounds against someone named Grover Wiley in his final fight, at age 43.
Oscar De La Hoya, 26
Before: 29-0, en route to undisputed status as the highest-earning fighter in history.
After: 10-6, including 8-6 in his last 14 fights, with losses to Bernard Hopkins, Floyd Mayweather, Manny Pacquiao, Felix Trinidad and two to Shane Mosley.
Jack Dempsey, 29
Before: 60-4-9 and retired as heavyweight champion after just nine years as a pro.
After: 1-2 after launching a comeback at age 31 against new champion Gene Tunney, who won both fights by decision, sandwiched around a Dempsey win over Jack Sharkey.
Roberto Duran, 29
Before: 71-1, including eight years as lightweight champion and two knockout wins over his only conqueror, Esteban DeJesus.
After: 32-15, beginning with a victory over Sugar Ray Leonard. In the rematch, Duran said “No mas,” and his career went into decline, though he did briefly hold the middleweight title.
Joe Frazier, 29
Before: 29-0 and defeated Muhammad Ali in their epic first fight at Madison Square Garden.
After: 3-4-1, beginning with the first of two destructive knockout losses to George Foreman, and including two more fights with Ali, one of them the debilitating “Thrilla in Manila.”
Emile Griffith, 29
Before: 52-7 and the reigning middleweight champion after two welterweight reigns.
After: 33-17-2, including 1-6 in title fights. Lost his last three fights at age 39.
Larry Holmes, 35
Before: 45-0 and within four victories of matching Rocky Marciano’s record for victories by an undefeated heavyweight champion.
After: 24-6, starting with three victories that got him within one of Marciano, then consecutive losses to Michael Spinks twice, and Mike Tyson. Won his last four fights, the final one at age 52.
Evander Holyfield, 37
Before: 36-3-1, including 28-0 to begin his career, with title reigns at cruiserweight and heavyweight, two wins over Tyson, and an epic trilogy with Riddick Bowe.
After: 8-7-1, lost heavyweight title to Lennox Lewis, won one bid for a paper championship, lost several others, still fighting at age 48.
Jack Johnson, 43
Before: 53-6-7 during a historic heavyweight championship reign in which he crossed the color barrier.
After: 2-5 after a 1923 comeback, at age 45, following a three-year layoff. Before the comeback, Johnson had not fought a title bout in eight years, and few legitimate opponents afterward.
Roy Jones, 35
Before: 48-1 with few close bouts and the only loss via disqualification in a fight he was winning.
After: 5-7, with four violent knockout losses. Classic example of a speed-based fighter whose core skills were exposed when his athleticism slipped. Money problems have him still fighting, at 42.
Jake LaMotta, 29
Before: 77-14-3, including a middleweight title reign and five of his six fights with Sugar Ray Robinson, one of them a victory.
After: 6-5-1, beginning with a successful middleweight defense against Laurent Dauthuille in Detroit. Stopped in 13 rounds by Robinson in next fight and was finished as a legitimate contender. Three of four career stoppage losses came during this period.
Sugar Ray Leonard, 31
Before: 34-1 with title reigns in three weight divisions and wins over Marvin Hagler, Thomas Hearns and Roberto Duran, the latter avenging an earlier defeat.
After: 2-2-1 after the Hagler win, beginning with a victory over Donny LaLonde. Lucky to get a spurious draw with Hearns, beat Duran long past their primes, then lost to Terry Norris and Hector Camacho.
Joe Louis, 36
Before: 58-1 and set the all-time record with 25 consecutive heavyweight title defenses.
After: 8-2, beginning with a 15-round decision loss to Ezzard Charles in his last title fight. After stringing together eight wins, lost his final bout on a disturbing knockout by champion-in-waiting Rocky Marciano.
Willie Pep, 26
Before: 134-1-1 and almost six years as reigning featherweight champion.
After: 95-10, beginning with his first loss to Sandy Saddler in their historic series, which was the undoing of Pep.
Sugar Ray Robinson, 30
Before: 123-1-2, with five wins over his only conqueror (Jake LaMotta), as he built a career widely acclaimed as the greatest in boxing history.
After: 50-18-4, including five straight wins to run his record to 128-1-2, after which he lost his middleweight title to Randy Turpin. He would regain the title three more times but his invincibility had vanished.
Sandy Saddler, 25
Before: 125-8-2, including title reigns twice at featherweight and once at junior lightweight, and one of boxing’s most memorable rivalries against Willie Pep.
After: 19-8, during which he regained the featherweight title from an aged Pep in their fourth fight (he was 3-1 in their series). He kept the title until he retired but lost seven over-the-weight, non-title bouts in the interim.
Michael Spinks, 31
Before: 31-0 and became the first reigning light heavyweight champion to win the heavyweight championship.
After: 0-1 after finally deciding to fight Mike Tyson. In 91 seconds, his reluctance was explained conclusively, and Spinks was finished as a fighter.
Mike Tyson, 30
Before: 44-1, unified the heavyweight title, lost only to Buster Douglas, served a rape sentence, and became one of the most recognizable figures alive.
After: 6-5, beginning with a successful title defense, after which he lost twice to Evander Holyfield. Last title bid, vs. Lennox Lewis, was an execution.
Mickey Walker, 30
Before: 75-10 with lengthy title reigns at welterweight and middleweight, and an unsuccessful bid at light heavyweight.
After: 19-10-4, including a draw with Jack Sharkey in a heavyweight title bid, in his first fight after turning 30. He never won another title fight.
Pernell Whitaker, 33
Before: 39-1-1, with a decision loss to Jose Luis Ramirez that ranks among the worst in title-fight history, and a draw with Julio Cesar Chavez that many believed Whitaker won.
After: 1-3, with one no-contest, a streak that began with Whitaker’s final win, vs. Diosbelys Hurtado. The loss to Oscar De La Hoya was disputed but the ones to Felix Trinidad and nondescript Carlos Bojorquez weren’t. Whitaker had a victory overturned by a positive drug test during this time.