MONDAY, July 11, 2011 (HealthDay News) -- Older adults have to exercise more than younger adults in order to maintain muscle size, according to a new study.
Researchers examined how much exercise was needed to maintain or increase muscle mass, size and strength in adults ages 20 to 35 and ages 60 to 75.
In the 16-week first phase of the study, all the participants did three sets of resistance training exercises (leg press, knee extensions and squats) three times a week. In the 32-week second phase, participants were dividing into three groups: some were assigned to stop resistance training altogether, some were told to reduce training to one day a week, and others were asked to cut down training to one day and one set of resistance exercises (as opposed to three sets) a week.
In the younger adults, muscle size was maintained in both groups that reduced their training. This was not the case in the older adults, whose muscle size shrank even if they did one to three sets of the exercises one day a week.
However, one day of resistance training a week was enough for both younger and older adults to maintain their strength -- at least for an extended period of time.
"We are not advocating that people only train one day a week indefinitely, but we do believe such a program can be effective during temporary periods when it is difficult to maintain a consistent, intensive exercise regimen several days per week," study leader Marcas Bamman, of the University of Alabama at Birmingham, said in a news release from the American College of Sports Medicine.
The study appears this month in the journal Medicine & Science in Sports & Exercise.
"Our data are the first to suggest that older adults require greater weekly maintenance dosing than younger individuals to maintain resistance-training-induced increases in muscle mass," Bamman added.
Bamman said all adults "should include progressive resistance exercise in their weekly regimen, but there will always be times, such as extended travel or a family illness, when exercise is difficult to sustain." In such cases, the study suggested, resistance exercises once a week are certainly better than none.
The U.S. Centers for Disease Control and Prevention has more about strength training for older adults.