INDIANAPOLIS – While muscle strength can be maintained by exercising just one day per week, a report released this month by the American College of Sports Medicine (ACSM) says that older adults may need more frequent exercise than their young counterparts to maintain muscle size.
The report, titled “Exercise Dosing to Retain Resistance Training Adaptations in Young and Older Adults,” was published this month in Medicine & Science in Sports & Exercise®, ACSM’s official scientific journal. This two-phase exercise trial, led by Marcas Bamman, Ph.D., sought to determine the appropriate exercise dose to maintain muscle mass, muscle size and strength in older (between ages 60 and 75) and younger (between ages 20 and 35) adults.
“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,” said Bamman, who is a researcher with the University of Alabama at Birmingham. “Stopping exercise altogether – called detraining – leads to significant strength reductions after just a few weeks. Our team sought to determine how little exercise a person needs to maintain strength.”
Seventy adults – 39 in the younger age group and 31 in the older age group – completed the first phase of the trial, which lasted 16 weeks. In phase one, participants performed three sets of three resistance training exercises – leg press, knee extensions and squats – three times a week. Fifty-six participants completed phase two of the trial, which lasted 32 weeks. In phase two, participants were randomly sorted into three reduced training groups. The first group stopped training altogether. The second group reduced training to one-third, decreasing exercise days from three to one. The third group reduced training to one-ninth, both decreasing exercise days from three to one and also reducing training sets from three to one.
Results indicate that improvements in strength can be retained for an extended period after training ceases. While once-a-week exercise is sufficient to maintain strength, there are age-specific differences in the required dose to maintain muscle size. Within the younger group, there was a dose-response such that one-third exercise volume continued to increase muscle size, one-ninth exercise volume maintained size and detraining caused atrophy. In the older group, no group maintained muscle size. Older adults likely require more frequent training to maintain muscle mass gained from resistance 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,” said Bamman. “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.”
The American College of Sports Medicine is the largest sports medicine and exercise science organization in the world. More than 40,000 international, national and regional members and certified professionals are dedicated to advancing and integrating scientific research to provide educational and practical applications of exercise science and sports medicine.
Medicine & Science in Sports & Exercise® is the official journal of the American College of Sports Medicine and is available from Lippincott Williams & Wilkins at 1-800-638-6423. For a complete copy of the research paper (Vol. 43, No. 7, pages 1177-1187) or to speak with a leading sports medicine expert on the topic, contact the Department of Communications and Public Information at 317-637-9200 ext. 133 or 127.
The conclusions outlined in this news release are those of the researchers only and should not be construed as an official statement of the American College of Sports Medicine.