“It made me really curious about my mom,” Wittenberg said. “There’s no question there are generations of women who didn’t get to pursue their potential.”

Smith was the daughter of a military family in the 1960s. Her father died of a heart attack at 42, when she was 17, and her mother was killed a year later in a plane crash. Bereaved, she enrolled at the University of Hawaii as a business major and began dating a runner. She joined him at the track and would do a lap or two, which soon turned into a few miles. She ran the Honolulu Marathon, as one of about 20 women.

Not everyone was excited to see women at the starting line.

“When I ran that marathon in 1975, doctors would say, ‘This is no good for you; you won’t be able to get pregnant; your uterus will drop; you’ll get varicose veins,’” she said. “I wouldn’t listen to it. But that mind-set about women and fitness was pervasive.”

When Smith moved to Los Angeles the next year, a new challenge awaited. She met the creator of one of the first fitness leotard lines and modeled for her. She took one of the first women’s aerobics classes in the country, called Body Design by Gilda, alongside Jane Fonda and Barbra Streisand. Participants were urged: “Stretch out those love handles! Watch those thighs disappear before your eyes!”

By 1977, she was teaching her own style of aerobics to women in Los Angeles — an athletic departure from the Jazzercise classes so popular at the time. Drawing on her business degree, she began making recordings of her classes and sold millions of workout videos, becoming a regular on talk shows like “The Merv Griffin Show” and the morning shows.