Kids are building self-confidence and staying fit, while training to become an American Ninja Warrior.
Classes at Chicago's Ultimate Ninjas recreation center are designed and led by American Ninja Warriors who train to conquer the same obstacles seen on the TV show.
Michael Torres has been on American Ninja Warrior for the past four seasons.
"I started when I was 21 and every season is something new," Torres said. "I get butterflies every single time."
Torres is one of the trainers teaching children how they can become an American Ninja Warrior too.
"Training as a Ninja, you could say, is pretty much hanging onto whatever you can," Torres said. "We do a lot of efficiency training, that means getting on and getting off an obstacle as quickly and as fast as you can."
Torres called it a "huge mental game, as much as it is a huge physical game."