Contestants on NBC's "American Ninja Warrior" need motivation — after all, they're putting their mental and physical fitness to the test while trying to complete a seemingly impossible obstacle course. And on an upcoming episode, high schooler Hans Hertz has the most heartwarming incentive for challenging himself: his little brother, Harper Hertz.

"Harper is my hero. He inspires me every day," Hans says in a clip of the episode, shared with POPSUGAR. At 3 months old, Harper was diagnosed with a rare genetic disorder called Rubinstein-Taybi syndrome (RTS), which affects many organ systems and causes growth delays, distinctive facial features, and intellectual disabilities. "All the challenges he faces, he does so with a smile on his face," Hans says.

Just starting its 15th season, "American Ninja Warrior" has seen a huge number of competitors [1] come through its course — but watching people tap their inner strength to tackle the obstacles never gets old. And for Hans, the training had a special meaning, providing him with an opportunity to spend quality time with his brother.

"'Ninja' definitely makes me and Harper very close," Hans says in a voice-over, as he's shown training for the show alongside his brother. "I'm so happy that I get to share this moment with my brother Harper."

You can watch the outcome of Hans's attempt — and see Harper cheering him on — here [2], and catch the full episode on NBC on June 5 at 8 p.m. ET/PT.