It is back to ''business as usual'' this weekend for Britain's most successful athlete of the modern era.

Oarsman Steve Redgrave emerges from another winter of gruelling preparation to take his place in the boiler-room of the men's coxless four when Britain's team takes part in the first round of the Krombacher Rowing World Cup, currently being staged in Munich.

That Redgrave considers this weekend's challenge in such a matter-of-fact way is yet another indication of the steely resolve this remarkable competitor has.

To make it to the start-line again in this most demanding of sports, the 36-year-old four times Olympic champion has had to come to grips with some new challenges. These include being diagnosed as a chronic diabetic over the winter, while more recently, his reigning world champion combination has had to cope with replacing of crew-mate Tim Foster, who severed four tendons in a hand in a freak accident that will count him out for at least this year's early competitions.

However, neither of these

difficulties, nor a significantly stronger bunch of opponents, will get in Redgrave's way this year. Earlier this week, while acknow-ledging that he faces a tougher challenge this year than last when his new fours combination went into unknown territory before going on to win the World Cup series and the world title, the meticulous Redgrave said: ''I don't expect any surprises.'' From him, that is a statement of calculated fact rather than an optimistic pre-race soundbite.

Put plainly, no British sportsperson has achieved more than Redgrave. Just listing his achievements is tiring work. His roll of honour includes four Olympic gold medals and one bronze - including Britain's only title at Atlanta, gained with partner Matthew Pinsent; seven world golds and three silvers; three Commonwealth golds in his only Games appearance in 1986 at Strathclyde Park; and the award of an OBE followed by a CBE from a grateful nation. In addition, he is the only person ever to be given the honour of carrying Britain's flag at the Olympics twice.

Perhaps more than his

impressive array of glittering prizes, this statement puts his unique achievements in perspective - Redgrave has come first in every single race of his championships career since the spring of 1992 - when he was suffering from colitis.

In his usual focused style, Redgrave has coped with this winter's challenges. ''It was a real shock when I was told I was diabetic,'' he says, ''and it took me three or four months to come to grips with it. Now, I'm fairly confident it's under control through insulin and management.''

Redgrave takes insulin injections four or five times a day. ''It's not a huge issue now. It's more of a pain in the neck,'' he says. But he does admit the problem has changed his approach. ''Before I used to 'graze' through food, now I eat one large meal a day and up to five small ones. I have to monitor closely what's happening.''

He also has to have a daily calorific intake of more than 6000, so unless he is careful, there is plenty opportunity for his body management to go completely awry. Thanks to his approach, it is as unlikely as Redgrave opting for a Gazza-style kebab.

Speaking about his enforced crew change, Redgrave says: ''While I was struggling with the diabetes, the other three (Pinsent, Foster and James Cracknell) had a good winter. I was playing catch-up throughout our training''.

Now, Foster's accident has ''put us into turmoil in preparing for this first race''. Foster's place will be taken by Luka Grubor. He is new to the British squad this year, having recently gained citizenship. Previously, he represented Yugoslavia and later his native Croatia at junior world level. He carries Redgrave's seal of approval: ''He is a good substitute and the right man for the job.''

After his Atlanta triumph, Redgrave famously invited anyone who saw him near a boat to shoot him but, persuaded by a huge sponsorship deal from financial giant Lombard, and the fact he missed the sport, he came back.

''My decision was to carry on to Sydney and that's what I intend to do,'' he now says. Reviewing progress since then in his quest for a unique fifth successive Olympic gold - including this winter's set-backs - he adds: ''At this stage, I think we'll be there or thereabouts.''

He also says: ''If there were signs that I couldn't compete at the level I want to compete at - I would think again, but I repeat, I don't expect any surprises.'' While Redgrave continues the sport's most outstanding career this weekend, Glasgow's Katherine Grainger takes her first solo steps on to the top-class world stage. Having won the world Under-23 title in coxless pairs last year, before following it up with a bronze in Britain's women's eight at the senior world championships, Grainger, now resident in Edinburgh and a member of St Andrew, opted for the single sculls slot this year.

She won the right to be considered as Britain's top sculler at the winter trials when she deposed Olympic finalist Guin Batten. Two weeks ago, in what was for her a trial international regatta in Germany, she was second in a world-class field. This weekend will hopefully underline that she has the capability of breaking through at the very top level on her own.