Miriam Nelson

By Christine Gorman

OCCUPATION Research scientist and author of the Strong Women series

GOAL To persuade women of all ages of the health benefits of weight training

QUOTE "I love it when a 75-year-old woman shows me her biceps."

In 1994 Miriam Nelson and Tufts University colleagues proved that lifting weights doesn't just build muscles. It also strengthens brittle bones and reduces osteoporosis risk in older women. Ever since, she's been crusading to reacquaint women with their biceps, triceps and hamstrings. "We value our skin, breasts and hair," Nelson says. "But we don't value our muscles as much as we should."

Though it's never too late to start, Nelson urges women to begin pumping iron at least by their 30s and 40s, because that's when bones start to thin. Lifting weights for 30 min. two to three times a week can slow or even reverse that bone loss. Don't be worried about bulging muscles; women produce too little testosterone to really bulk up.

Nelson, 40, who just began rock climbing with her husband and three children, believes doctors don't talk enough about what women with osteoporosis can do to help themselves. But she's too good a scientist to claim that weight training is a cure-all. Her latest book, Strong Women, Strong Bones (Putnam), the third of a series, also includes up-to-date nutritional and drug therapies for osteoporosis. "There's no magic bullet," Nelson says. "But strength training can mean the difference between having a vibrant old age and a frail one."

--By Christine Gorman