Jake Gyllenhaal has taken up free running.

The 29-year-old star admitted he pushed himself harder than ever when he took up the French martial art - known as Parkour - in order to get into perfect physical condition for his role in video game-based action movie 'Prince of Persia: The Sands of Time'.

He explained: "We worked really closely with David Belle, who invented Parkour. I worked with a lot of gymnasts. I started jumping off of a lot of things that were padded and learned the fundamental stuff, and then slowly started working on harder surfaces, really carefully. And I'd say, 'OK, I'll try it,' and then I'd say, 'Oh God! Oh please.' But then I'd get it, and we'd go a little further and a little longer and a little higher and just kept it up.

"I never did anything this intensive before to change my body. It's a physical role. And when I commit to playing a part, it's 110 per cent."

The difficult technique - which involves training to overcome any obstacles in the most efficient way possible - also boosted the actor's confidence, though he admits he ended up scaring himself by taking on some difficult stunts for the film.

He added to People magazine: "It got a little bit dicey there near the end, when they saw that I liked doing things that were dangerous. I tried my hand at things that were pushing it a little bit. There was this big 35 foot jump that I did that got a little hairy."