Bernie Ecclestone has questioned the rationale behind Michael Schumacher's increasing outings on two wheels, suggesting the German racing legend is risking 'getting himself seriously injured'.

Schumacher claimed a record seven world drivers' titles during his career in Formula 1 from mid-1991 to the end of 2006, and since stepping down from the top flight has conducted a number of tests aboard Casey Stoner's championship-winning Ducati MotoGP bike.

In addition to that the 39-year-old made his maiden racing appearance on a KTM machine at Misano in Italy last month - finishing an impressive fourth having dropped back as far as 14th early on, with the race's second-fastest lap to his name to boot [see separate story - click here].

Now, however, F1 supremo Bernie Ecclestone - a man who started out as a motorcycle dealer himself - has added his concerns to those of former Ferrari team principal Jean Todt, pointing to the irony of Schumacher's latest 'hobby' given how much of a vociferous campaigner for improved safety he had been during his time in grand prix racing.

"In Formula One he was always pushing for more and more safety," the 77-year-old is quoted as having said by two-wheeled website Visordown. "Now he's racing a motorcycle!

"I don't quite understand why he would now risk getting himself seriously injured. It makes no sense to me."