Unlikely as it may seem, pumping iron may be a good way to reduce the number and severity of falls among frail nursing home residents, even those as old as 96, according to a study published recently in the Journal of the American Medical Association.

Researchers from several Boston hospitals, including Beth Israel and Tufts, studied nine frail elderly men and women, most of whom were over 90; the participants were residents of the Hebrew Rehabilitation Center for the Aged in Boston who worked out three times a week for two months on a weight-lifting machine. All showed "highly significant and clinically meaningful" strengthening of the quadriceps, the muscles in the front of the thigh that straighten the knee and are important in walking.

The volunteers, most of them women, were not in very good shape when they began the weight-training program. Seven had arthritis, six had heart disease, and four had hypertension. But none had unstable medical conditions, and all were ambulatory.

"Our observations regarding the safety of strength training, even among the frail elderly with underlying cardiovascular disease, should be emphasized, because the known hazards of immobility and falls outweigh the potential risks of muscle strengthening," the researchers concluded.

Muscle weakness is considered a major factor in the prevalence of falls, the leading cause of accidental death among people over 85. According to the National Institute on Aging, which helped sponsor the Boston study, about one third of all those over 65 who live at home suffer falls. The weakened muscles that lead to falls place such people at a threefold risk of being admitted to a nursing home within a year, according to the NIA.