Advancing health through science, education and medicine

News Releases

Stay in touch. Sign up for our core media list, and you’ll get the latest news sent straight to your inbox.

Military Assignments May Decrease Aspects of Physical Fitness

by User Not Found | Aug 01, 2011
Study shows deployment has mixed effects on physical fitness

INDIANAPOLIS – Physical training is part of the job of U.S. Army soldiers, but access to physical fitness facilities and training time may be limited during combat deployments. While limited training may result in a loss of fitness, the physical requirements of warfighting may offset some of the negative effects. According to a study released today in the September issue of Medicine & Science in Sports & Exercise®, the official journal of the American College of Sports Medicine (ACSM), the effects of deployment on fitness are not as large as expected.

In the context of the ongoing military actions in Afghanistan and Iraq, no previous study had assessed the effects of prolonged military deployment on body composition, physical fitness, and physical performance. Researcher Marilyn Sharp, M.S., and her team from the U.S. Army Research Institute of Environmental Medicine measured physical fitness levels in 110 infantry soldiers before and after a nine-month assignment to Afghanistan. Measurements included aerobic fitness, muscle strength, muscle power, and body composition.

Soldiers maintained strength and lower body power during deployment. They experienced small, but statistically significant, decreases of about 5 percent in both aerobic fitness and upper body power. Changes in body composition were both positive – a decrease in weight (2 percent) – and negative – a decrease in lean body mass (4 percent) and an increase in fat mass (8 percent).

“These findings are encouraging in that the body composition and physical performance changes were not large,” Sharp said. “However, it would be wise to track soldiers during longer deployments to ensure that no health or performance concerns arise.”

Reduced physical training time may be a contributing factor to the decline in aerobic fitness. For average healthy adults, ACSM and the American Heart Association recommend that healthy adults exercise for at least 30 minutes, five days per week, at a moderate intensity, or 20 minutes, three days per week, at a vigorous intensity. Prior to deployment, a majority of soldiers were meeting the recommendation, 80 percent of soldiers exercised three or more days per week, Though most soldiers reported having access to some form of aerobic and strength training equipment, only 35 percent exercised during deployment.

On a positive note, it is likely that the physical demands of military tasks helped soldiers to maintain physical fitness even in the face of reduced training time.

“The good news is that the negative effects of this deployment were minor and could be quickly ameliorated upon return with a directed physical training program,” Sharp said.


NOTE: 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. 40, No. 9, pages 1687-1692) 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. 127 or 133. Visit ACSM online at

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.

Featured Publication

Learn more about the full library of ACSM's certification resources, such as ACSM's Resources for the Exercise Physiologist, ACSM's Resources for the Personal Trainer, ACSM's Certification Review, and more. With ACSM's comprehensive textbooks, you are on your way to a successful career...
» Read More