Military Health Expert Explains how Strength is Relative to Body Weight

Military Health Expert Explains how Strength is Relative to Body Weight

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The military monitors its service members' fitness levels to ensure combat physical readiness and minimize loss of personnel to injury.

Each military service selects its physical fitness tests to meet its unique mission needs. All services' fitness tests include measures of aerobic fitness, such as a timed run, and muscular health, such as the push-up. Depending on the service, the fitness test can include sprinting, carrying weighted items, or deadlifts.

Strength is relative

A 2024 study published in the Journal of Strength and Conditioning Research by the Defense Health Agency-Public Health Injury Prevention Branch in Aberdeen, Maryland, highlights the importance of muscular strength relative to a person's body weight in predicting physical performance.

"Public health investigations have shown that military physical fitness tests provide insights into key components of physical performance and injury risk," says Tyson Grier, a health scientist at DHA-PH and lead author of the study.

In 2022, the U.S. Army changed its fitness test from the three-event Army Physical Fitness Test to the six-event Army Combat Fitness Test, or ACFT. This was the first change to the Army's test in 42 years. The ACFT includes six events ranging from muscular strength, endurance, and power to anaerobic and aerobic fitness.

The absolute amount of weight deadlifted, known as raw strength, is not the only measure of strength. Grier notes that accounting for an individual's body weight appears to be especially useful in predicting physical fitness.

"Relative strength, which factors in a person's body weight, is important because it represents an individual's ability to control and move their body," says Grier. "To calculate relative strength from the deadlift, you divide the amount of weight deadlifted by your body weight. For example, if you deadlift 300 pounds and weigh 200 pounds, you would have deadlifted 1.5 times your body weight."

Grier's investigation showed that by adjusting the deadlift results to relative strength, greater relative strength was associated with higher physical performance. Men deadlifting ≥1.5 times their body weight and women deadlifting ≥1.25 times their body weight outperformed those with lower relative strength (within their own sex) on all ACFT events.

What strength training is recommended?

According to the Physical Activity Guidelines for Americans, adults should engage in at least 150-300 minutes of moderate-intensity aerobic activity a week. In addition, individuals should do muscle-strengthening activities, of moderate- or greater-intensity muscle-strengthening activities that involve all major muscle groups (legs, hips, back, abdomen, chest, shoulders, and arms) two or more days a week.

Muscle-strengthening activities include free weights, resistance machines, push-ups, and exercises with bands. For injury prevention and technique tips for common weight-lifting exercises, see the deadlift, squat, and bench press factsheets available in the DHA-PH resource library.

Ideally, a certified trainer will help develop specific individual exercise plans or group plans that are modifiable by fitness level. In general, Grier recommends the following based on the American College of Sports Medicine guidance:

• For each major muscle group, aim to do two-to-three sets of eight-12 repetitions, or "reps," with good form.
• The last rep should be difficult.
• Increase weight slowly over time so the effort feels like an eight of out 10 (where 0 is no effort and 10 is your maximum effort).

Are there Benefits for Strength Training Aside from Meeting Military Standards?

While the Department of Defense will continue to use fitness tests to measure physical fitness of service members, adding muscle-strengthening workouts into your exercise routine can help every adult by:

• Enhancing your quality of life by improving your ability to do everyday activities such as lifting boxes, mowing, and vacuuming.
• Keeping bones strong.
• Reducing your injury risk.
• Managing a healthy body weight and chronic health conditions.

Additional information sources:

U.S. Military

• DHA Injury Prevention for Active Duty Personnel
• Uniformed Services University-Consortium for Health and Military Performance (CHAMP), Human Performance Resources

Army

• M 7-22, Holistic Health and Fitness, section 4-23: Muscle Strength Training
• Health and Holistic Fitness Integrators
• Armed Forces Wellness Centers
• U.S. Army Physical Fitness School

Navy

• Physical Readiness (navy.mil)
• Navy Physical Readiness Program (2024 updated policy)

Marine Corps

• USMC Human Performance Branch, Quantico, VA
• Physical Fitness for Marines - Research Guides at Library of the Marine Corps

Air Force

• Fitness Program
• U.S. Air Force fitness program

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