Aston drivers Alonso and Stroll to start Brazil F1 sprint from pitlane

Aston Martin is treating Saturday's sprint as a glorified test to be in better shape for Formula 1's Brazilian Grand Prix

Fernando Alonso and Lance Stroll will start Brazil's sprint race from the pitlane after making sweeping changes to their Aston Martin F1 cars.

Alonso and Stroll both struggled for speed in Friday's sprint qualifying, only managing 16th and 19th respectively.

In response to the result and in a desire to further hone in on their car set-up for the remainder of the weekend, both Aston Martins have undergone changes under parme conditions, which means they have to start from the pitlane.

The FIA document specified that both the bodywork specification and the suspension set-up of Alonso's and Stroll's cars have been changed overnight.

Sauber's Zhou Guanyu, who qualified last, has also had his suspension set-up changed and will line up behind the two Astons at pit exit.

Speaking after qualifying, Alonso had already suggested that he would treat the 24-lap sprint as a practice session, calling the race "useless" from his lowly grid position.

"The sprint for us really means nothing, as there are only eight cars scoring points," the two-time world champion said. "And even if you are eighth or seventh, you score one point or two. So just the format doesn't reward anything to be fast on Friday night and Saturday.

"For us there's much more focus on Sunday, so that's the way we treat the sprint weekends. A little bit useless until Saturday afternoon. And it's the case on this one as well."

Alonso explained set-up experiments following Friday's sole practice session had also been one of the reasons why the Aston Martin team's qualifying session had been so low-key.

"We didn't have the pace in qualifying," he said. "We made some changes also after FP1 that we knew were maybe detrimental to the pace of the car. But we had to keep ourselves focused on Sunday more than Saturday, so for us, the sprint is more a free practice."