There's no denying the incredible strength and stamina it requires to endure obstacle course races like Tough Mudder and the Spartan Race. It's impressive enough to complete them, let alone competing against adults as a 9-year-old. Milla Bizzotto was the youngest competitor to participate in a 24-hour obstacle race that was designed by US Navy Seals. In the video above, you'll get a glimpse of her training, which spanned nine months -- three hours a day, five days a week.

The South Florida native didn't compete in the race just for bragging rights. Her intention was to raise awareness against bullying. Milla started out training with her dad and coach, Christian Bizzotto, as a way to build self-confidence and strength after being bullied at school. "I think the bullying thing has died down without her having to take physical action just because her outlook is so much different now that she knows how to defend herself,"Christian told CBS Miami. Since then, she's competed in other races including Battlefrog 24 -- which features hundreds of obstacle courses and 36 miles -- and the Spartan Race last year, which she completed with her dad and grandma.

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