SAN DIEGO -- A torn anterior cruciate ligament injury is one that we usually hear about in professional athletes, but many doctors are seeing it with alarming frequency in young people, especially in children who play soccer skateboard or snowboard.

It takes a lot of practice and many falls to become a world champion, according to women’s world champion skateboarder Lyn-Z Adams Hawkins.

Adams Hawkins said, "I have taken quite a few spills.”

Adams Hawkins and her brother, Tyler, are risk-takers.

"I am an adrenaline junkie; you could say I love that feeling of my heart going,” said Tyler Adams Hawkins.

The siblings also share a common injury.

"I was skating this big handrail and came down stiff legged and it just popped,” said Tyler.

Lyn-Z Adams Hawkins said, "I landed with my legs straight, and you just hear it, and you feel it pop.”

Both Lyn-Z and Tyler are recovering from torn ACLs, an injury to the ligament in the center of the knee.

Rady Children’s Hospital orthopedic surgeon Dr. Han Chambers said, “If you have a twisting injury like this or like that, it can tear that ACL."

Chambers said ACL injuries are an epidemic in soccer, snowboarding and skateboarding, especially among females.

"There's probably three times more girls have this injury that boys,” said Chambers.

Chambers said the reason is, “The girls land different than boys.”

According to Chambers, girls tend to use their quadriceps more than their hamstrings and also tend to land more upright and with straighter knees than boys. These differences tend to cause girls' knees to be less stable and more susceptible to injury during athletic activity.

"If they can land with their knees flexed and all their muscles working in the right time then they have fewer injuries,” said Chambers.

Lyn-Z Adams Hawkins works to avoid future knee injuries by keeping her muscles strong and flexible by working out and then working to end risky tricks by landing safely.

"I was positive and just worked really hard to make sure I did my rehab and just really came back strong,” said Lyn-Z Adams Hawkins. She spent six months in rehabilitation and wears a knee brace to prevent twisting.

Chambers said, “Fortunately with the surgery that we do now and the physical therapy, we are able to get all of these kids back to sports."

Lyn-Z and Tyler are back performing radial tricks and looking forward to many happy landings.

An untreated or unsuccessfully treated ACL injury in children or teenagers may result in future knee problems, according to medical experts.

Over time, osteoarthritis may develop.

Children who have ACL tears often need a reconstruction because conservative treatment does not work, medical experts said.