I had a good laugh the other day when I heard David Beckham say that the training regime at AC Milan would keep him playing until he was 40.
Watching Wayne Rooney and lads such as Paul Scholes and Ryan Giggs doing the business for Alex Ferguson at Old Trafford in midweek, I couldn't help but laugh again at Beckham's comments.
I watched Beckham play at the weekend and I can honestly say that I would have been mobile enough to do the amount of running he did.
If the effort he put in is any indication of how hard he will work over the long term for Milan, I reckon he could still be playing when he's 50 and, through the miracle of modern medicine, still be a clothes horse for the mega brands. Good luck to him.
Rooney is far from handsome but, for the football fan, he's a thing of beauty. There was a banner in the crowd for the Carling Cup clash against Manchester City which read "No10, Rooney -- The White Pele."
He has many of the qualities which made Pele so great and, in years to come, I have little doubt that he will take his rightful place among the names that Manchester United fans revere.
It is almost hard to believe now that the tabloid media in the UK aimed so much abuse at Rooney while he did his growing up in public.
On a nightly basis, comedians and chat show hosts lampooned Rooney as a thick, raw-faced footballer from the north of England and ridiculed his relationship with his wife, Colleen.
He was, and is, only a young lad, and it must have been very hard to cope with. Even last season, while he suffered in silence under the sulky shadow of Cristiano Ronaldo, every time his understandable irritation rose to the surface, he was jumped upon and the same old tired headlines dredged up again.
Rooney swallowed his anger over two seasons while Alex Ferguson showered his attention on Ronaldo. He spent much of that time out on the left wing, tackling back and doing the work the Portuguese winger should have been doing.
He is a lad who lives for the game, and that's obvious. He was prepared to work for the team because he instinctively understands that his prodigious attacking qualities are nothing if they are not supported by a good defence and a strong midfield.
But none of that was important to the headline writers. Maybe they were upset that Rooney and his wife have played their own game and become a low-key couple instead of the new Beckhams, the role the media had anointed for them.
This season, though, the penny has finally dropped. It took 21 goals and some outrageous skill to convince those who have been so critical of the lad that he is the type of player that could win you a World Cup.
At the moment, he's the only reason why Ferguson and Manchester United still have a big interest in every competition except the FA Cup.
His goals have hidden the weakness at the heart of Ferguson's squad and, without him, it's hard to see how Manchester United could have maintained close contact with Chelsea and Arsenal at the top of the Premier League table.
But the biggest beneficiary of Rooney's red-hot form could very easily by Fabio Capello, who is fortunate enough to be the England manager while Rooney is approaching his prime.
I've always said that the really great players generally hit their peak at 27, so Rooney still has two or three seasons to go.
But I don't think he's far off his best, and Capello is smart enough to know that every plan he makes for the World Cup in South Africa should have Rooney at the heart of it.
If he takes the World Cup by storm, Ferguson will have mixed feelings. The vastly complicated financial affairs of the Glazers at Manchester United have led some to speculate that Rooney might be sold by the club.
For me, that would signal the end of Ferguson's time as United's manager. He could not tolerate such a sale and hope to maintain the competitiveness of his team.
He sold Ronaldo and didn't fill the gap; he refused to pay the money required to secure Carlos Tevez's services and replaced him with Dimitar Berbatov.
He could not replace Rooney and I believe he would walk away if the decision was forced on him.
Ferguson knows that the future of this group of players rests on Rooney's shoulders and, by extension, the future of Manchester United.
Players such as Paul Scholes and Ryan Giggs, brilliant as both of them were against Manchester City, will help carry the load for a while more but, over the long term, Rooney must shoulder the burden, and I have no doubt that he's up to the job -- if he's still at Old Trafford to do it.