Simone Biles has revealed the painful cost of gymnastics greatness will contribute towards making next year's Tokyo Olympics her last.

The 22-year-old, who last year became the first woman to win four all-around world titles in Qatar, is adamant there is no chance of extending her extraordinary reign beyond next year.

Citing a series of relatively minor injuries and a strenuous training programme which have left her body feeling like it is "falling apart", Biles is already planning for her future beyond the sport.

Biles said: "I definitely plan for the Tokyo Olympics to be my last. I feel like my body's gone through a lot and it's kind of just falling apart - not that you can actually tell but I really feel it a lot of the time.

"I am in pain most of the time but it kind of feels right because if you are not in pain, it is almost like you could be doing more."

Biles has evolved into an outspoken advocate for her sport both in and out of competition, having taken a leading role in defending the victims of the sexual abuse perpetrated by the former US Gymnastics team doctor, Larry Nassar.

But Biles, who spoke last year of feeling "empowered" after speaking out about the abuse she herself suffered from Nassar, said she does not believe that horrific cycle of events will prevent countless other young gymnasts striving to emulate her.

"I feel like since it happened in the US, the gymnastics world took a really hard hit," admitted Biles.

"But I feel like you hear horror stories in every other sport too. Besides the amount of people it affected, it happens in the everyday world."