Michael Phelps picks Arizona as training base ahead of Rio 2016

Eighteen-time Olympic gold medallist Michael Phelps has confirmed that he will prepare for Rio 2016 at Arizona State University.

The American swimmer, who is the most successful Olympian of all time with 22 medals, was previously based at the North Baltimore Aquatic Club.

However, this week, the 29-year-old revealed on Twitter that he will head to Arizona with his swimming coach Bob Bowman.

Phelps wrote: "I am pumped for Bob, this is a great opportunity for him and I know he will be successful in building a great program at ASU. He has been there for me throughout my career and he will always be my coach.

"I'll continue to train under him in Arizona and look forward to following the training program we have set in place as we work towards 2016."

Phelps, who recently served a six-month suspension following a drink-driving conviction, retired from the sport after London 2012, but announced his return in April last year.