The arrest and conviction of former Penn State football coach Jerry Sandusky, brought to light a problem that experts say is affecting more than 39 million Americans: sexual abuse. 

But for Kayla Harrison, who gave the U.S. its first judo gold medal in Olympic history on Thursday, it was more than just headlines.

Harrison says she uses her weakest days to make it all the way to the top: the 2012 US Judo Olympic team.  Harrison defeated Britain's Gemma Gibbons in a final she dominated from the start, getting a stronger grip on Gibbons and managing to throw her twice.

"It's not every four years. It's every day," Harrison said. "I'm just so honored to be America's first gold medalist, and so happy to realize my dream. I'm America's first gold medalist in judo -- and always will be."

Harrison, a 22-year-old Middletown, Ohio, native who lives in suburban Boston, went to the medal podium determined not to cry. After one note of "The Star-Spangled Banner," she succumbed.

But for three years, she lived with a secret.  She was sexually abused by her former coach when she was 13 years old.

“I didn’t know what to do, what to expect or what to say,” explains Harrison.

An investigation by ABC's "20/20" revealed 36 swimming coaches were banned by USA swimming for allegations of sexual misconduct.  Last year Don Peters, who coached the 1984 US Olympic gymnastics team, resigned amid allegations of sexual abuse.

“It’s no longer a secret that just happens behind closed doors,” says Dr. Debra Day, a licensed psychologist.

Day says often young girls are groomed into a sexual relationship before they even realize they are involved in it.

"They become distorted in what they believe is happening,” says Day.

Harrison says she thought she was in love.

“In my mind it was a full blown relationship.  I was brainwashed.”

Experts say often a power paradigm is involved.  Predators will start to make the victims feel like they are more special than their peers.

“I spent every minute with Daniel and he was really good at making me feel like he was the only one I needed,” says Harrison.

The National Council of Youth Sports has been trying to find the best way to screen coaches for at least a decade.  And the US Olympic Committee also announced it would centralize and standardize background check programs across all 32 Olympic sports.  But Day says parents can help by looking for unexplained behavioral changes in their child and asking questions.

Harrison did what most victims can't do.  She pressed charges and faced her abuser in court back in 2008.  Daniel Doyle was sentenced to 10 years in federal prison and banned from Judo for life.

“He turned around and he said ‘I love you’ and then I never saw him again,” says Harrison.

She turned her dark days into a positive, ranking second in the world.

“Although it feels like you are in a prison and you can’t get out, you can and there is help out there and there are people who care,” she says.