Kovalainen gained weight for 2009

(GMM) Heikki Kovalainen bucked this winter's trend by actually putting on a significant amount of weight.

While most of his rivals shed kilograms ahead of the introduction of heavy KERS systems, the McLaren driver revealed he now weighs nearly 5kg more than he did one year ago.

Finn Kovalainen, 27, trained hard with a new physio and intentionally wanted more muscle mass, the Finnish newspaper Helsingin Sanomat said.

His centerpiece exercise was cross-country skiing.

"I now weigh 4.5 kilograms more than I did at the same time last year," said Kovalainen, who now weighs 65kg.

The introduction of KERS makes it an unusual time for a driver to put on weight, but Heikki insists the move was right for him.

"Personally I feel considerably better now. I have no pressure to lose weight," he said.