Michael Schumacher said he was shocked that fellow drivers were being so nice to him after proving his fitness at the second pre-season testing session yesterday.

The seven-times Formula One world champion, who has come out of retirement for Mercedes, managed over 100 laps in Spain and his quickest time was just over a second slower than Sauber's pacesetter Kamui Kobayashi.

"I'm surprised about their reactions, everyone is very pleased for me to be back but I know things will change on the race track," the 41-year-old German, who has recovered from last year's neck injury, told reporters in Spain.

"I feel fresh out of the box. So far it's all about as many laps and kilometres as possible. It's not so much about finetuning yet."

Times in testing give little indication of race pace given cars have different fuel loads. Refuelling during races is banned this season so teams will have to start grands prix with full fuel tanks.

Newcomers Virgin had to halt their second day of testing because the front wing of Timo Glock's car came off and the team did not have enough spare parts to fix the problem.

Ferrari's Fernando Alonso and world champion Jenson Button in the McLaren again put steady laps on the clock amid expectations the two teams have recovered from last year's problems and will challenge at the season opener in Bahrain on March 14.

Tomorrow's tests will be performed by the other main drivers on the team rosters including Felipe Massa in the Ferrari and McLaren's Lewis Hamilton.