DVIDS – News – Does body mass define a soldier’s fitness level?

By V. Hauschild, Army Public Health Center
ABERDEEN PROVING GROUND, Md. — The Department of Defense recently updated its 20-year-old policy that establishes body composition and physical fitness standards for active duty service members to ensure optimal physical readiness.

Revised DoD Instruction 1308.03 states that all service members “will maintain physical readiness by possessing the body composition and aerobic and anaerobic fitness necessary…to perform in accordance with their service-specific military requirements, missions, and specialties.”

The cornerstone of the policy is the body fat standard which defines the range of acceptable body composition for active duty members. A person’s body fat percentage, or “% BF,” is a scientifically valid physical indicator for assessing health status.

“Scientific evidence supports the same %BF military standards recommended by the previous version of the policy,” says Dr. Bruce Jones, Medical Officer and Chief Scientist of the Health Center’s Public Health and Epidemiology Branch. US Army public. “The policy update clarifies how simpler metrics can be used to estimate a service member’s %BF and makes allowances based on fitness testing.”

DOD policy differentiates standards for males and females due to well-established physiological gender differences in body fat. The standard states that men on active duty must maintain a %BF between 18 and 26, and women must maintain a %BF between 26 and 36.

“The most common way of estimating how much body fat a person has is called the body mass index,” says Jones. “BMI is calculated from a person’s height and weight. It is a quick, inexpensive and scientifically accepted screening tool to identify overweight and obese people.

BMI is used by the National Institutes of Health, World Health Organization, Centers for Disease Control and Prevention, and many health care practices to determine a person’s obesity classification and risk long-term health impacts and deaths. The four classification levels, which apply to all men and women in the general population over the age of 20, define a BMI below 18.5 as underweight, a BMI between 18.5 and 24, 9 as normal or healthy, a BMI between 25 and 29.9 as overweight and a BMI over 30 as obese.

BMI compares relatively well to more accurate %BF measurements, such as air displacement plethysmography, water displacement, or dual-energy X-ray absorptiometry.

While BMI has value as a screening tool, it poses limitations as an accurate measure of body fat for some people, Jones says.

For example, because BMI does not reflect fat distribution, the index cannot identify those who carry the most fat around the waistline, which may mean greater health risk. A waist circumference measurement can provide an indication of long-term health risk, but will be misleading if not adjusted for size.

Additionally, BMI does not take into account lean body mass, which is the portion of a person’s weight that comes from body components other than fat, including muscle. For this reason, a very fit, muscular person who weighs the same as a non-muscular, thick-waisted person of the same height will have the same BMI!

It is also possible that a healthy, muscular person has a BMI slightly above the NIH/WHO/CDC “normal” range and is not truly “overweight”. Studies have shown that people who fall into this category make up a small percentage of the overall population and typically only slightly exceed acceptable or normal BMI standards.

Because all NIH/WHO/CDC BMI classifications apply to adults, regardless of age, fitness, or gender, the military sets its own standards for soldier acquisition and retention.

Army standards, called weight-for-height standards, differ slightly from NIH/WHO BMI classifications in that the former include a small portion of men whose BMI would place them in the “overweight” range. from the NIH/WHO/CDC. This adjustment, which extends the “normal” range for soldiers to a BMI of 27.5, takes into account the potentially larger muscle mass of some soldiers.

Tyson Grier, a kinesiologist with the APHC Injury Prevention Branch who has studied the use of BMI in soldiers, says that despite the Army’s adjustment, a higher BMI generally indicates more body fat, not more of muscle mass.

“A soldier with a BMI between 25 and 27.5 puts him in the low end of the general population’s overweight BMI category, but his %BF may meet the DOD standard,” says Grier. “However, we still have other soldiers who exceed the standards.”

According to APHC’s 2020 Health of the Force report, 17% of soldiers are classified as obese according to WHO/NIH classifications (HoF pages 20-21). These service members do not meet DOD or Army standards.

Another APHC IPB expert, Dr. Joseph Pierce, says that while BMI and adjusted weight standards for army height provide an important measure of optimal physical readiness, there are trade-offs between composition body and fitness types.

“Soldiers with a higher BMI tend to perform better on tests of strength and power, such as heavy lifting, but not as well on aerobic endurance tests, such as running two miles, while soldiers with a lower are more successful in aerobic events like running.” says Pierce, lead author of a recent study on soldiers’ BMI and physical abilities.

Soldiers with very low BMIs also have higher injury rates across fitness levels, Jones says. This finding underscores the risks of being underweight and the need to ensure that weight control efforts do not lead to excessive dieting or weight loss.

Although DODI 1308.03 establishes body composition parameters required for all active duty military personnel, it also allows for a range of body sizes and physical fitness tests necessary to meet service-specific needs.

Importantly, Jones says, the updated policy now allows military services to consider members who fail body composition standards but score exceptionally high on their physical fitness test. The policy does not specify how each service will implement this change, but excelling in physical fitness tests may allow some soldiers to exceed body fat standards.

The policy also requires the Army, Air Force, Navy and Marine Corps to maintain physical fitness programs and monitor the number and types of injuries each year to ensure personnel can s perform their duties in a manner that reduces the risk of physical entrainment. wounds. The policy allows each department to determine its own fitness testing methods and standards to meet the unique needs of its mission.

For its physical fitness tests, the Army chose the Army Combat Physical Fitness Test to replace its 40-year-old Army Physical Fitness Test. The recently revised six-event ACFT includes gender- and age-adjusted standards and replaces the leg tuck with the plank.

Military personnel should maintain a %BF as specified by DODI 1308.03 and applicable service-specific procedures to optimize their health and readiness:

• Review this BMI fact sheet to better understand BMI and recognize that since muscle weighs more than fat, improving fitness and increasing muscle mass does not always translate to weight loss.
• Achieve weekly targets of the Military Physical Activity Performance Triad, or P3.
• Refer to P3 tips for nutrition, sleep and activity.
• Use Army Wellness Centers to help achieve weight management goals, including monitoring body fat using their specialized body fat assessment equipment called BodPods.
• Because being underweight can lead to a higher risk of injury and excessive or too rapid weight loss can be dangerous, seek advice from your health care provider or a designated professional through your local AWC.

The U.S. Army Public Health Center focuses on promoting healthy people, communities, animals, and workplaces through the prevention of disease, injury, and disability of soldiers, retirees, family members, veterans, civilian military employees, and animals through population-based surveillance, surveys, and technical consultations.

Date taken: 04.12.2022
Date posted: 04.12.2022 13:54
Story ID: 418347
Location: WE

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