MotoGP champion Marc Marquez has explained the cause of a nasty highside in the opening minutes of Friday practice for the German Grand Prix.

The Repsol Honda star, chasing an incredible nine wins in a row this weekend, was launched from his RCV while at full lean on the long, slow left hand second turn of the Sachsenring circuit.

The young Spaniard landed hard on his head, causing neck pain, and was slow to get to his feet. However the 21-year-old was back on track by the middle stages of FP1 and finished the session in sixth.

"Definitely no injury. Yes big pain in the neck, but it is not a problem on the bike as you could see in FP2 when I was able to do a good rhythm and many laps. Maybe I feel a little tired now but tomorrow should be better," Marquez told the official MotoGP website.

"It was a bit strange for me to understand what happened at first, but we checked the data and it was completely my fault. I was going through turn two in second gear and then I didn't know but I touched the gear lever and accidentally selected third gear.

"At that moment I was full lean and not ready, so when it engaged I had the highside."

Marquez went on to lead most of the afternoon session, only losing the top spot to Aleix Espargaro when the Forward Yamaha rider fitted the special Open class soft rear tyre at the very end of the session.

Marquez's team-mate Dani Pedrosa also suffered a big Friday accident, losing the front of his RCV in the afternoon session.