Muhammad Ali vs. Leon Spinks I

Following the bout, Ali fought against Jean-Pierre Coopman, Jimmy Young and Richard Dunn, with the latter bout being the final bout in which Ali scored by knockout. Later in 1976, Ali participated in an exhibition bout in Tokyo against Japanese professional wrestler and martial artist Antonio Inoki.[25] Though the fight was noted as a publicity stunt, the fight affected Ali's mobility as he suffered leg bruises throughout the fight due to Inoki's kicks.[25] Ali suffered two blood clots and an infection in the fight, which was ultimately declared a draw.[25] Ali fought against Ken Norton again in their third fight at Yankee Stadium in September 1976, where Ali won by a heavily contested decision, which led to the audience booing in the ring. Ali reacted to the fallout of this by announcing a brief retirement to practice his faith in Islam, having converted to Sunni Islam after falling out with the Nation of Islam the previous year.[26]

After winning against Alfredo Evangelista in May 1977, Ali struggled in his next fight to boxer Earnie Shavers that September, who pummeled Ali a few times with punches to the head. Ali later won the fight by another unanimous decision, but the Shavers fight caused Ali's longtime doctor Freddie Pacheco to quit after he was rebuffed for telling Ali he should retire. In February 1978, Ali faced Leon Spinks, who had a 6--0--1 record going into their first fight at the Superdome in New Orleans, and lost the title by unanimous decision. Ali later won against Spinks by unanimous decision in their rematch eight months later, making him the first heavyweight champion to win the belt three times. Following this win, on July 27, 1979, Ali announced his retirement from boxing. His retirement was short-lived, however, after Ali announced his comeback to face Larry Holmes for the WBA belt in an attempt to win the heavyweight championship an unprecedented fourth time. It was around this time that Ali started struggling with vocal stutters and trembling hands.[27] Ali's rapid decline caused concern and Ali checked himself into the Mayo Clinic for checkup, later declaring him fit to fight. Ali fought against Holmes on October 2, 1980 in Las Vegas with Holmes easily dominating the weakened Ali, who had taken thyroid medication to lose weight though the medication left him visibly tired and short of breath. Ali's trainer Angelo Dundee stopped the fight in the eleventh round, citing the only Ali fight in which the boxer lost by knockout. The Holmes fight is said to have contributed to Ali's Parkinson's syndrome.[28] Despite pleas for retirement, Ali fought one last time on December 21, 1981 in Nassau against Trevor Berbick losing a ten-round decision. Following the bout, Ali announced his retirement."