Alison Haislip & Blair Herter enjoy champagne while flying to Japan. American Ninja Warrior. December 12&19. Only on G4.

Alison Haislip & Blair Herter ride Japan's subway. American Ninja Warrior. December 12&19. Only on G4.

Alison Haislip & Blair Herter find themselves lost in the Japanese woods. American Ninja Warrior. December 12&19. Only on G4.

Olivia Munn recounts her experience with Kevin Pereira at Sasuke 21 in Tokyo, the first time they ran the 'Ninja Warrior' course.

Olivia Munn outlines some surprises in Stage One of the new 'Ninja Warrior' course to the contestants in the American Ninja Warrior Challenge. Spoiler alert: They made it h...

At Camp Pendleton, Ninja Warrior veteran, Paul Terek talks about what it takes to be a true Ninja Warrior.

Go behind the scenes with free runner Levi Meeuwenberg and gymnast Mark Witmer as they battle it in the American Ninja Challenge 2.

Go behind the scenes with Rick Seedman and Brian Orosco as they duel in the American Ninja Challenge.

Kevin runs down the accomplishments and legendary status of Sasuke's biggest celebrity, Nagano.

Here's a look at one of the American Ninja competitors, a stuntwoman and free runner named Luci Romberg.