As they grow older and recognise that the universe is larger than a sports arena, it becomes difficult for athletes to shut out everything else and to play a game. It also hurts more. The human body was not designed to withstand punishment for almost 12 months of the year.
It was not designed to fight for the heavyweight championship at the age of 37, either, Earlier this week, I caught up on television with the contest in Los Angeles that saw Lennox Lewis extend his reign over the division when a gaping eye wound left Vitali Klitschko in no fit state to continue beyond the sixth round. Wearied by the lumbering activity, frequently out-punched, marked up and two points adrift on the official score cards, Lewis, in sporting terms, looked old. Time to quit? That time was more than a year ago when a lighter, sleeker, better-organised Lewis battered Mike Tyson in Memphis.
Watching Lewis slump heavily on to his stool took me back to 1978 when Muhammad Ali regained the World Boxing Organisation title from Leon Spinks in New Orleans. Giving away 11 years, Ali toyed for two rounds with the idea of knocking out Spinks but the work he had put in could not bring back the snake-tongue quickness of the hands. Ali missed badly with two rights. Then yielding to reality, he simply moved around and about Spinks, flicking punches, holding, sliding, holding, always three moves ahead. It was a boring and decisive victory and it must have hurt like hell. A sourness had invaded Ali's style. "It's murder how hard he has to work,'' his trainer Angelo Dundee said.
In truth, Ali, along with Joe Frazier, should have retired three years earlier after they fought themselves to a standstill in Manila. Knowing when to go. That's the thing.
Fourteen months after Ali's victory in Louisiana he crumbled against Larry Holmes, who implored the referee to stop the contest. A year later, Ali lost a 10-round decision to Trevor Berbick. At last, it was over. Nine contests too late.
Since it is Lewis's intention to fight on we can only conclude that the truth hasn't dawned, not only the long-term risk to his health but the prospect of being remembered as less than he was.
Oblivious to the discernible effects of a hard career, Evander Holyfield, now 40, announced yesterday that he is negotiating for a contest against James Toney. At a similar age, Frank Bruno appears to be serious about coming out of retirement.
"Enough is enough,'' the Welsh boxing sage Eddie Thomas said to Colin Jones after three unsuccessful attempts to win the world welterweight championship. Financially secure, Jones has never regretted taking Thomas's advice. "I was out of the ring at 27 and never tempted to return,'' he said. Barry McGuigan, prompted by the harsh truth he encountered in abortive combat, retired in his 28th year.
Across the past decade big-time sport has become an explosive growth industry. That's fine for many investors and lots of the performers, but "growth industry'' is no buzz phrase for fun. Newspapers and broadcasting organisations have concentrated on the high salaries and prize money available in sport. That doesn't mean simply, as some suggest, that the rich athletes all become complacent. It does mean that many work harder and longer and so may wear out sooner.
These days, motivated athletes respond to the physical effects of age by conditioning themselves more intensively. The high level of competence achieved by the England rugby union team springs in a number of cases from the efforts of men in the twilight of their careers and playing tactical games with time. They find no prejudice against age in selection. Harder and harder hits haven't driven them into retirement. But what does the future hold; arthritic joints, knee and hip replacements? The ageing athlete measures pain against glory, risk against profit. He considers what is left of his body, and then, I believe, he subconsciously decides whether or not he wants to go on.
Pat Eddery's decision to quit race riding at 51 wasn't taken prematurely. It sprang from a clear understanding that time waits for no athlete.