*Former track champ Marion Jones is out promoting her new book this week and has done several interviews in which she expresses regret in lying to federal investigators about using performance enhancing drugs.

That, and her role in a check-fraud scam, are what landed her in prison for six months in 2008, during which she spent a month and a half in solitary confinement after fighting another inmate.

“I surely wish that I could go back and change certain things in my past, on one hand, but then I wouldn’t be who I am today, someone who I’m actually really proud of,” Jones said in an interview with The Associated Press. “If I hadn’t gone through certain things, and because I had those six months or whatever — just a lot of quiet time — if I hadn’t gone through it, I don’t know if I would ever have that much time to reflect. A lot of people don’t.”

Her 213-page book “On the Right Track,” is based in part on letters Jones wrote to her husband, Obadele Thompson, while she was in a federal prison in Fort Worth. The book contains a harrowing depiction of Jones’ stay.

“I didn’t have a sentence that was a slap on the wrist. I wasn’t sentenced to an institution that I kicked back in a hammock for my time there,” she said, punctuating that point with a chuckle. “It was tough.”

Jones writes about fearing her life was in danger during a five-minute tussle with a roommate. Jones says she emerged uninjured, but the other woman’s face “was bruised and bloody.” In the interview, Jones called her ensuing trip to solitary confinement “probably the worst part of my life.”

“There were moments while I was there, where you just feel like you cannot go on: ‘How in the world can I make it to tomorrow?'” Jones said.

She writes in depressing detail about prison conditions and specific personnel; about inmates using empty toilet paper rolls threaded through toilets as a sort of telephone; about being chained to her seat during a “ConAir” flight with other prisoners on a trip to another jailhouse.

In the book, Jones describes her “Take a Break” philosophy: Before making an important decision or taking an action you might later wish you hadn’t, force yourself to pause and consider what’s right. She discusses her “Take a Break” approach when she visits schools around the country, something she first did as part of her probation and now does on her own.

“By helping people, it’s a form of healing for myself, because I hurt so many people. I know that,” she said. “I still struggle with knowing that I let a lot of people down. I disappointed a lot of people that love and care for me, worldwide, and when I think about that it kind of gives me the motivation to kind of keep going on.”

Below, Marion Jones on today’s broadcast of “Good Morning America.”