Loose forward Sam Warburton has made a shock retirement announcement at the young age of 29, the widely respected Welsh rugby player unable to overcome injuries. Here's a potpourri of early sports retirements.

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Sam Warburton retires: Wales and Lions great calls time on rugby-playing career aged 29
Björn Borg
Maybe the biggest shock retirement ever - the Swedish tennis legend quit at the age of 26 in 1983, 11 grand slam titles already in the bag. Burnout, life under a spotlight, had proved too much. "When I was playing tennis it was very difficult to do the other things in life. And you come to a point when it is difficult to have a normal life," he said.
Borg recently told the Guardian: "I'm happily married. I have a great family. We live outside Stockholm. The clothing company is doing very well. We have a quiet life with the kids. I'm happier than I've been for many, many years."

George Best
The Manchester United and Northern Ireland football genius retired close to his 26th birthday. He did reappear, but for most intents and purposes this was it. "I'm sick of United," his column ghost writer claimed Best said around this departure point. "I've got nothing against the management. It's the team. It's just not good enough. It's just not going anywhere." The old phrase "he's got more clubs than Jack Nicklaus" did actually apply to Best after that, as he dealt with a life in headlines and his alcohol addiction. But the real Best, the extraordinary footballer, was gone by then.

Steffi Graf

Steffi Graf...doesn't look back. Photo / Getty Images
Steffi Graf...doesn't look back. Photo / Getty Images

The German tennis superstar not only quit at 30, she did so on the eve of the US Open saying her "motivation wasn't what it was in the past. I have done everything I wanted to do — I'm not having fun anymore," said Graf, declaring herself perfectly fit. She had been number one for 377 weeks, and won 22 grand slams when she walked away in 1999. "I just don't think of my career much," she said three years ago. "You have no idea how quickly your career disappears, or you just don't even think much about it ... it was gone so fast and just on to a different life."

Lorena Ochoa
Mexico's Ochoa, the world number one for a record 158 straight weeks, quit professional golf in 2010 aged just 28. "Your life looks great and I enjoyed travelling, the glamour, it was amazing," Ochoa said this year. "But for me, getting married and having a family, that was more important. Now that I'm a mother, I wouldn't change that for anything in the world and I feel blessed." Ochoa had 27 event victories, two major titles and is fourth on the all time earning list having won nearly $22m.

Stu Wilson

All Black star Stu Wilson...on yer bike. Photo / Dean Purcell
All Black star Stu Wilson...on yer bike. Photo / Dean Purcell

The All Black wing and captain — two words not normally associated together — quit at the age of 29, in 1983. The lean try scoring ace was promptly thanked for his great service by being banned for seven years, after taking the proceeds of a book during the allegedly amateur rugby era.

James Ryan
Former All Black coach Laurie Mains thought Ryan could become one of the great locks. Ryan never gave himself a chance, quitting the game at the age of 25 nearly a decade ago. Injury was a contributor but the Sunday News quoted a Ryan "confidante" saying: "He told me he has had enough of living in the goldfish bowl that All Blacks have to live in when they are in New Zealand. "He said he has no interest in rejoining the All Blacks and spending the best years of his life in that environment." The Highlanders forward — who studied law — played nine tests over two seasons. Two years ago, when he was working as an account manager in London, he was included in a rugby writers Highlanders dream team despite having played just 25 games for the province.

Dean Lonergan
The Kiwi forward quit the game aged 26, soon after his finest moment in a young Kiwi side's upset 1991 win over Australia in Melbourne. West Aucklander Lonergan, whose career included a brief stint with the Canberra Raiders and 11 tests, went on to re-shape New Zealand sport as a promoter/manager in professional and charity areas. His triumphs include setting heavyweight boxer Joseph Parker on a course to a world title fight. In a Herald profile, Lonergan recalled going to Carlaw Park to watch league as a kid with "total glee". The game had channelled his youthful aggression, and given him a start in the promotions game.

Chris Borland
The rising San Francisco 49ers linebacker quit after his rookie season, aged 24, saying he had suffered more than a dozen concussions, most of then unreported. He described the sudden transition to a far less regimented life as difficult. "If you gave me an hour in the day between '09 and '14, I could have told you exactly where I was and what I was doing. It's still something to get used to. There's no amount of advice or book you can read. I wouldn't say it went entirely smoothly."

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