May 16, 2002 -- One workout a week can mean the difference between frailty and freedom. A new study shows that it takes just a little exercise for older adults to keep up their strength.

"One day per week seems to be effective," write Scott Trappe, PhD, and colleagues in the April issue of the Journal of Gerontology: Biological Sciences. "Older adults could engage in a low-volume, high-intensity resistance training program and still maintain independence and reduce their chances for falls and injuries."

Trappe's team wanted to see just how little exercise would keep an elderly person strong. They signed up 10 70-year-old men who had not been exercising. All of the men built up their strength in a 12-week program in which they did weight training three times a week. At the end of this program, the men had a 50% increase in muscle size and strength.

Half the men then went back to sitting on their butts. The other half did the same weight-training exercise, but only once per week.

The men who stopped exercising got weaker. The men who worked out once a week stayed strong.

The researchers point out that older people often lose muscle size and strength -- a condition known as sarcopenia. It's one of the main causes of the falls and injuries that lead to loss of independent living. They note that even 90-year-olds are able to handle training programs that build up their overall strength. And now, they say, it looks like just one good workout a week is all it takes.