Michael Schumacher has warned his F1 2010 rivals that his 'energy is back completely' and his 'batteries are fully-loaded' again following a three-year break from the top flight - and with the first pre-season test now little more than a week away, he admits that it is 'about time to start this whole thing'.

After agreeing terms with Mercedes Grand Prix shortly before Christmas to make what has been described as the greatest comeback in sporting history, Schumacher's preparations for his return began in earnest with a three-day GP2 Series test for Super Nova at Jerez last week.

He subsequently reported that he had felt no lingering ill-effects from the motorcycling-induced neck injury that had prevented him from substituting former Ferrari team-mate Felipe Massa at the Scuderia last summer in the wake of the Brazilian's life-threatening Hungaroring qualifying accident.

What's more, the record-breaking seven-time F1 World Champion advised the current breed of young guns that at 41 years of age he may now be into his fifth decade, but a comprehensive winter training programme has left him fighting fit - and fully-prepared to withstand the stresses and strains of the cut-and-thrust of front-running F1 competition. Make no mistake - 'Schumi' is back, and with a vengeance.

"The after-effects of that accident have been gone for a long time," he told his personal website, reflecting on his Cartagena motorcycling fall just under twelve months ago. "That's why I was sure that my neck would not cause any problems. It was a year ago; it's over. I have been practising physically very carefully since December and feel extremely fresh and fit.

"That was one of the reasons why I felt so good in the car at Jerez, but then Formula 1 is another thing. The G-forces are higher, so it's not really comparable. That is why I'm looking forward so much to testing [the new Mercedes F1 car] in February. Only then will the old feeling be completely back. I can't wait!"

Confessing to a sense of 'relief' when he initially hung up his helmet three years ago following 16 seasons spent in the full glare of the world's media that had left him feeling exhausted and in need of a rest, Schumacher reflected that his prolonged sabbatical - what had started out as retirement, until the racing bug bit again - has done wonders for his enthusiasm and motivation.

Moreover, he makes it patently clear that he is back for one reason and one reason only - to add to an extraordinary career CV that already boasts no fewer than 91 grand prix victories, 154 podium finishes and a staggering 1,369 points.

"After my retirement at the end of 2006 I was very happy," the Kerpen native acknowledged. "I felt relief, just like freedom. I enjoyed that feeling, because especially in the last two years F1 had demanded a great deal from me - not the racing, which I loved all the time, but all those things which relate to living under constant observation.

"It did me extremely well to be quiet for those three years; it really is as if my batteries are fully-loaded. My energy is back completely. I really notice how the prickle is coming, how motivated I am because I'm so looking forward to this competition.

"We have a clear aim - we want to win the championship. That is my personal standard too, and that's what we will fight for from the beginning. The constellation we have here is pretty unique - with Ross [Brawn] and his world championship-winning team, with the know-how of Mercedes, with the best engine at the moment...and we want to use that. It is about time to start this whole thing."