The man who holds the world record for hand walking was born without legs. Here's how he trains for a powerful and strong upper body.

• Zion Clark has caudal regression syndrome, which meant he was born without legs.
• He grew up in foster care and was bullied, beaten, and underfed, he told Insider.

Zion Clark is a successful wrestler and a Guinness World Record holder for walking on his hands. While he's now found fame in sports, his childhood was marked with personal trials. Clark was born without legs and raised in foster care. He told Insider he was bullied, underfed, and physically attacked in foster homes and his schools.

But when Clark was adopted by his mom at the age of 17, he finally felt supported and loved, and he started to turn his life around.

Clark, who recently released a book 'Zion Unmatched,' set a world record for the fastest 20m walking on hands, with a time of 4.78 seconds.

He told Insider how he found optimism, despite his early childhood, and described how he trains for a powerful and strong upper body.

Clark's wrestling career took off after being adopted

Clark was born with caudal regression syndrome which affects 1-2 in every 100,000 people.

He was immediately placed in foster care and bounced around nine different foster homes in Ohio and New York until the age of 16, he said.

"I had to deal with trying to survive on my own and just make it through life because a lot of these families were just there for a check," Clark told Insider. "I was the kid that they got for the wrong reason."

Clark started wrestling at school, but even before then he was "fighting to protect" his life and was punched in his sleep by other foster boys, he said.

At age 16, he met Kimberlli Clark Hawkins, who was already a foster mom to various girls.

Clark said the foster care system had given up on him by this point, and he had no other options.

So Hawkins took him and adopted him after seven months.

"They made it seem like I was the absolute worst kid on the planet, but my mom didn't believe them," Clark said.

With a stable family behind him, he was able to focus much more on school and sports, and went on to achieve success academically and on the track. He also became one of the best wrestlers in the state, he told Insider.

Clark trains hard, focusing on explosive movements

Clark now trains most days a week, both on the mat and in the gym. His workouts are designed to boost his wrestling prowess by focusing on explosive, quick exercises like medicine ball slams, banded dumbbell presses, pull-ups, and dips.

His favorite exercises are box jumps: "They generate a lot of explosive power I can use to transition to wrestling, track or any other athletic endeavors," Clark said.

He also uses the assault bike and performs hand drills - moving laterally and vertically around cones - to boost his cardio and speed on his hands.

Compound movements like bench press, shoulder press, and rows have also helped Clark build and maintain his upper body strength, he said.

But Clark values recovery as much as training.

"Recovery is where your muscles grow and respond to the workout you did," he said. "You don't have to train seven days a week to see results, ensure you are allowing time for your body to recover and rest so you can perform at your best."