We all face challenges, but sometimes life can present us with obstacles so big, we say to ourselves, “I just can’t do it. It’s just too hard.”

Jothy Rosenberg could have said those words when he was a 16 years old and faced a grim diagnosis of a rare bone cancer. He could’ve said it when they amputated his leg as a result, and he could’ve said it again three years later when the cancer spread to his lungs, forcing doctors to remove one. But he didn’t. Instead, this extreme athlete decided to take whatever challenge life dealt him, and face it head-on.

Now, decades later, he’s inspiring others with his story and his book called ‘Who Says I Can’t.’

Rosenberg stopped by the Fox News studios in New York City to talk with Dr. Manny Alvarez, the senior managing health editor of FoxNews.com.

Q. Despite the amputation and the removal of one lung, you still managed to become an extreme athlete. Why was this important to you?

A. I found sports was in fact the best way to recover. It’s not just physical. The things that happen to somebody in this kind of situation, the psychological effects are about as worse as the physical effects and it shatters your self esteem.

Q. Did you use sports as a way to change, and perhaps, eradicate any other poison from the cancer that might be ruining your system?

A. It really wasn’t the latter, although I am sure that it had a good effect. But I really focused on sports because it was something I could adapt. Skiing was the first thing.. I thought if I focused really hard, if I worked hard at it, and what I soon figured out was if I worked and focused harder on it than anyone else was willing to, I could not only get back to being an OK skier the way I was before I had lost my leg, but I could get to be as good or better than most “two-leggers.”

Q. What inspired you to write the book, and what inspired the title, ‘Who Says I Can’t’?

A. I needed not to write the book too quickly. I needed 25 to 30 years of figuring out things out for myself about how I’d recovered, what was important, and how to convey that message. I did not want to write another cancer book or amputee book, I wanted to write a book for everyone. And the name of the book came because people were constantly saying to me, ‘I bet you can’t do that.’ Somebody said to me, ‘Oh, it’s great that you love water skiing, but you could never barefoot water ski on one foot.’ So I spent 10 years trying to perfect that and did so.

Q. What’s the story behind the photo on the cover of the book?

A. I was the CEO of a company, and I wasn’t biking at the time, and there was someone working for me who was going to do the AIDS Ride from Boston to New York and that is an impressive feat for anybody. I was bragging about her and that I was going to donate some money, because it was a good cause, and somebody said to me – right to my face – ‘It’s such a shame that you’re so excited about this, and you could never do that.’ I went out and bought a bike that afternoon and named the book after that incident.

Rosenberg is also working on a TV reality series of the same name that profiles other individuals who’ve overcome various challenges to excel at an extreme sport.

For more on his story and the reality series, check out the related video.

Click here to read more about Jothy on his website.