Sideline Cut:As Muhammad Ali celebrates 65 years of a life that has become one of the most glorified of the 20th century, the question has turned from the why of his greatness and radiant appeal to whether it was all worth it.

Reading the tributes and reflections from The Champ's friends and ringside adversaries that have been splashed across the wires and newspapers since his birthday on Wednesday, you realise that for many those recollections of the days of thrills and laughter are now shaded by guilt and sadness. Ali is still young in terms of contemporary life-expectancy, but for many years now he has been trapped in the steel and velvet glove of Parkinson's disease, his voice, energy and dancing eyes all squeezed and stilled to the point where his friends have simply been unable to reach him.

For such an outrageous and shameless extrovert, that is a tough sentence and one he has borne without complaint and with absolute grace and good humour.

Ali's slow and well-advertised decline into the half light has made, of course, the famous features and books written about him all the more powerful and the fight material and the famous interviews with Michael Parkinson all the more wistful.

Long after Ali stopped fighting, successive generations came along eager to learn more of the way he love-bombed the western world and Africa with what amounted to an unashamed proclamation of his youth and energy and heritage.

More than any American, he lived out old Walt Whitman's bold proclamation: I celebrate myself and sing myself/And what I assume you shall assume/For every atom belonging to me as good as belongs to you.

One often reads of the actor or singer who could turn from frost to sunlight the instant he or she stepped in front of the crowd. But with Ali, the scale of the audience never seemed to matter. Whether hamming it up for the television cameras or receiving a profile writer in his private quarters, Ali simply enjoyed himself.

AJ Liebling, the gourmand, boxing academic and distinguished man of letters who wrote for the the New Yorker magazine in the mid-20th century, discovered this when he visited Ali in a Manhattan gym before his first professional fight, against a Detroit hopeful named Sonny Banks. While executing a rigorous programme of sit-ups under the supervision of Angelo Dundee, Ali proceeded to entertain the writer with a poem he had composed in honour of Floyd Patterson's recent victory over the Swede Ingemar Johansson.

"He is probably the only poet in America who can recite this way," Liebling wrote of watching Ali's sit-up/recitation. "I would like to see TS Eliot try."

The poem ended: If he would have stayed in Sweden/He wouldn't have took that beatin'.

Ali was still a glorious secret then, with only the press and other freeloaders bothering to turn up at Madison Square Garden. Within 15 years, he had become a mortal god. He was a wondrous, scarcely believable figure to black Americans struggling for equality over a century after the Civil War. He was reviled by the establishment and later hailed by liberals over his firm refusal to enlist in the army when the Vietnam War escalated. He became a strident advocate of black empowerment, embraced Muslimism and simultaneously dazzled African street kids and the New York intellectual and media set. And above all, he starred in thrilling, raw, boxing contests, fortunate to have blue-chip opponents like Sonny Liston and George Foreman and Joe Frazier against whom to pit his sharp wit, balletic grace and seemingly depthless well of courage.

When you scan the history of heavyweight boxing, from the brutal, bare-knuckle days to the seismic fights of the early 1900s, it was as though it was all building towards the transcendent epoch when Ali placed an often shady and bloodthirsty sport at the centre of the cultural and sporting landscape. He was, as he regularly pointed out, blessed with a physical beauty so at odds with the demolished noses and heavy-jawed hard men commonly associated with the ring.

And he was an eccentric, an individualist, a man who craved and needed public attention. As Norman Mailer - never a man to hide his own light under a bushel - wrote of Ali's first Joe Frazier fight, in 1971, "He is America's Greatest Ego."

Like many sportsmen, Ali was vain but he had the flamboyance to match. He had a disconcertingly dreamy certainty about his own destiny, happily getting a mock-up newspaper bearing the headline "Cassius Signs For Patterson Fight" after he returned to New York following the 1960 Olympics in Rome. It was for his friends down in Louisville to enjoy. "They won't know the difference," he said.

And when the time came to face Patterson for real, Ali was mean enough to taunt him verbally before he boxed him into submission, just as he would mercilessly rile and taunt Frazier over a decade later.

The world has revered Ali for so long now that it is often forgotten it was not an overnight status and that there was a long-deceased generation who believed him to be mouthy and unpleasant, altogether too big for his boots.

And some of that might have been true, but Ali's monologues or conversations - often one and the same thing - were peppered with such self-deprecation and humour that it was humanly impossible not to warm to him. He was never distant. And after his second coming from 1971 to 1975, as a mellower, more gracious 30-something, in those hellacious fights that now feature as the most precious cultural jewels of that lurid decade, the world's love affair with Ali was well under way.

And it continued through the desperate beatings he took from Earnie Shavers and later Leon Spinks and Larry Holmes and, finally Trevor Berbick, by which time even his own backroom staff were quitting, convinced that for Ali to continue fighting was not just dangerous but morally unforgivable.

Why did he do it? Perhaps it came down to the bottom line in boxing and in all sport: money. Or maybe it was vanity, his Achilles' heel, that common male failing of not knowing when your day is done.

Whatever the reason, he has paid the price. And it would have been easier, as the consequences of those poundings began to take possession of the husky voice and that famous physique, for Ali to disappear behind the mansions or, like Roosevelt, to choreograph his public appearances so that he could hide his infirmity. But no, his bravest feat, as raw and honest as any of those fevered, immortal rounds against Foreman, has been to keep on showing up.

It cannot have been easy for him to keep on meeting the public as the overwhelming natural handsomeness began to soften, the sing-song voice dried up and the body language he used, always so expressive and compelling, slowly and surely disappeared to the point where he can throw only old men's, slow-motion, shadow punches.

And yet the rest of the world flocks to meet him. He can still charm a room with his mere presence.

On the night Mike Tyson finally admitted he was just a ghost in the fight game after getting pummelled into middle age by the big Clones man Kevin McBride, Ali appeared at ringside and then, long after midnight, outside the interview room where Iron Mike spoke with that strange eloquence and lucidity of his. Everyone, from the scowling hip-hop gang who trailed Tyson to well-heeled Washington socialites, was drawn to Ali. It was like watching children flocking around Santa Claus. Tough men were smitten. Men and women wanted to touch him. Big McBride got the special treatment, an embrace and a few words from Ali, a lovely brushing with starlight for the blue-collar Ulster man.

Of course, this plump, lightly black man bore only a haunting resemblance to the young, preaching boxer who took the world by storm. But it was enough. They could walk away happy they had met The Greatest, perhaps pushing aside the awkward question of what it must be like being Muhammad Ali these days.