Four of the hottest young celebs in Hollywood were out flexing and flaunting their abs, pecs, biceps — you name it — on the beaches of Los Angeles this past weekend.

“Hills” star Audrina Patridge and “High School Musical” standout Ashley Tisdale were out showing off the latest in string bikini fashion, while “Extra” host Mario Lopez and Kennedy/Schwarzenegger spawn Patrick Schwarzenegger played “who has the least amount of body fat.”

Who do you think won their respective bikini and bicep beach battles? Click any photo above to see them all in a slideshow view, and then…

Vote here.

PHOTOS: Lots more Ashley Tisdale...

PHOTOS: Lots more Mario Lopez…

PHOTOS: Lots more Audrina Patridge…

PHOTOS: Lots more Patrick Schwarzenegger…

  • 8:27 AM ET