If you had bought into the inevitably childish pre-bout trash talking, then Bernard 'Old Popkins' Hopkins might have been expected to be seen clinging on to his zimmer frame when limping into the Planet Hollywood casino here to launch Saturday's light heavyweight showdown with Joe Calzaghe.

Instead, top to tail in dazzling white jeans, shirt and jacket as if determined for once to play the good guy, the man formerly in black weaved between the craps tables appearing about as youthfully fresh as it is possible for a 43-year-old veteran of countless ring wars to look. Just to ram home the point, he didn't ask for an invitation to remove said shirt and reveal a perfectly honed torso.

Hopkins is a rare mix of the irritating and the entertaining. In the ring, he could spoil, bore and butt for America; out of it, he could make Muhammad Ali sound tongue-tied such is his braggadocio. Yet even though you fancy them to be the empty boasts of a fighter who senses, as do the Vegas bookies with their odds of 2-5 on Calzaghe, that he's about to suffer a career-ending defeat, you must admire him as a model of athletic professionalism.

No sportsman is ever going to get better at 43. But even Calzaghe - in between suggesting mischievously "if I can't beat this old man I won't show my face in public ever again" - accepts it takes a special athlete to hold back the sands of time as effectively as the former decade-long middleweight champion and now holder of The Ring light-heavyweight crown.

In a way, he's the symbol of a changed boxing world, one where ageing fighters are thriving as never before. From Archie Moore to George Foreman, there have always been those who've defied the years but today, it's almost as if those one-offs have become the norm.

Of the world's top six pound-for-pound fighters rated by Ring Magazine, five are 30-somethings - including Calzaghe, who at 36 reckons he could still be a force at 40 if he hadn't set his mind on quitting after two more fights. The sport's biggest names?

All 30-plus, be it Floyd Mayweather (31), Oscar de la Hoya (35), or Roy Jones (39), himself a recent victor over 35-year-old Felix Trinidad.

One British boxing dream has already died this week at the fists of a man in his 40th year, with Clinton Woods, 35, getting a lesson from Antonio Tarver in their IBF light-heavyweight title encounter. Forty as the new 30 in boxing? It doesn't surprise Calzaghe's promoter Frank Warren.

"Boxers these days have improved training regimes, better diets, better conditioning and they're living the life of athletes and not fighting as often," said Warren. "Hopkins is a great example, a phenomenal athlete - no one must take that away from him. He doesn't cut any corners in preparation. I don't like to see boxers fighting in their 40s but he's an exception."

Never mind Hopkins's melodramatic stuff about having his heart of steel forged from prison and the ghetto and forget his tiresome verbal psychological warfare. What makes the man popularly known as B-Hop a danger to Calzaghe is something rather more prosaic; that is, as his conditioning trainer Mackie Shilstone insists, he has the most disciplined lifestyle he has ever come across in dealing with 3,000 elite athletes. Ricky Hatton he ain't.

"He told me at breakfast 'you know Mackie, this pomegranate juice, it's full of anti-oxidants'. I said 'Bernard I'm supposed to be telling you that'," laughed Shilstone. "He took part in an extensive metabolic study and it demonstrated his age is much younger from a performance standpoint - about 27 to 28 years old. Believe me, this is a very healthy man. He's going to live to be 100."

Heck, you wonder if he'll still be fighting at 100 - "Is this my last great challenge in boxing? No, that's to stay retired" he said here - but the way Hopkins sells it, Calzaghe will be facing the reincarnation of one of the most extraordinary fighters of any era.

"Yeah, when 19 April comes, Bernard Hopkins will resurrect 'the Old Mongoose' Archie Moore," he boomed." You'll see a 43-year-old pulling all the tricks out of the bag, neutralising the speed and all this dramatic stuff people say Joe does."

You've got to hand it to him. To dare compare himself to the legend whose incredible KO-littered 27-year career spanned fights with both Rocky Marciano and Ali and saw him win nine word title fights in his 40s takes some chutzpah. Still, as Hopkins will doubtless continue to tell us all week: "I'm extraordinary; Joe is just ordinary".