Cyclist Greg LeMond has seen ups and downs since he became the first American to win the Tour de France in 1986.
He's struggled with health problems related to a hunting accident early in his career, and was frozen out of the cycling scene over allegations that Lance Armstrong was doping, which later turned out to be true.
LeMond is back now with a new company called LeMond Bikes and a book called "The Science of Fitness."
He and his wife Kathy live in Medina, Minnesota.
The book, which was co-authored by Johns Hopkins University biologist Dr. Mark Hom, explores how exercise can affect your body at the cellular level.
LeMond's interest in the topic stems from his own health struggles following a hunting accident in the early 1990s that left lead pellets embedded in his body. He was diagnosed with Mitochondrial Myopathy, which can lower energy levels and lead to muscle weakness.
As he struggled with the condition, LeMond began to learn how mitochondria can boost health and how certain sorts of exercise can protect and strengthen mitochondria.
"Many people think that 'more is better' when you exercise, and a lot of studies are really coming out that anything over an hour of intense exercise can be detrimental," LeMond said in an interview with MPR's Cathy Wurzer. "For the average person, just being able to walk and get your heartrate up for short periods can lead improved mitochondrial density, which gives you more energy and changes your brain."
LeMond said the new book isn't just geared toward elite athletes, but can be useful even for people who can't be very physically active.
"I think cycling is one of the best ways, indoor cycling or outdoor cycling," LeMond said. "It allows people who aren't in condition to be able to walk on their bike, but also to accelerate and get their heart rate up slightly."
LeMond won the Tour de France in 1986, 1989 and 1990. Because Armstrong was stripped of his seven Tour de France wins following admissions that he used performance-enhancing substances, LeMond remains the only American to have won the race.