One Unit, Many Fitness Levels: Managing Training Load in Diverse Military Populations

By Seung Ho Choi

The Universal Challenge

I’ve had the opportunity to serve in both the Republic of Korea Army (18 months) and as a personal trainer for the Temple University ROTC program. Despite the cultural and organizational differences between the Korean and U.S. military, one reality remains constant: military personnel must be physically prepared to perform their duties. Whether it’s morning PT or mission-specific tasks, physical training is mandatory—not optional.

However, the approach to military physical training is often flawed. Unlike civilians, who train in gyms for personal goals such as health, competition, or recreation, soldiers are required to train, regardless of motivation. Ironically, this mandatory structure often leads to low engagement, underperformance, and higher injury rates, especially among those with limited fitness backgrounds.

This raises essential questions:

• How do we effectively manage training volume and intensity across groups of hundreds with vastly different fitness levels?

Fitness Variability and One-Size-Fits-All Training

One of the most overlooked issues in military physical training is the extreme variability in fitness levels within the same unit. It’s common to find former athletes (e.g., NCAA athletes and former high school athletes) training alongside individuals with minimal fitness backgrounds. Despite these differences, both groups are expected to complete the same physical tasks.

In theory, this promotes equality. In practice, it creates significant operational problems:

• Fitter individuals complete tasks more efficiently, often experiencing lower relative physical strain.
• Less fit individuals take longer to complete tasks but are still required to cover the same distances, exposing them to disproportionate physical stress and a significantly higher risk of injury.

A prime example is the ruck march—a common military event lasting hours. Regardless of fitness level, soldiers are expected to carry loads upwards of 50 lbs (20–25 kg). For unprepared soldiers, even moderate distances during ruck marches or load carriage accumulate significant musculoskeletal stress, leading to injuries that compromise both individual health and unit readiness. In fact, research has shown that over 50% of training-related injuries among infantry soldiers are directly attributed to ruck marching or distance running, with injury risk significantly increasing when loads exceed 25% of body weight or when ruck marches are performed frequently (Knapik et al., 2001).

Unlike athletic teams, where athletes typically share similar fitness baselines, military trainers face the challenge of programming for drastically mixed abilities. It’s unrealistic—and dangerous—to expect uniform performance in such diverse groups.

Smarter Programming for Military Populations

A. Fitness Group Splits

In an ideal world, each soldier would have a personalized program. In reality, especially with units of 100+ personnel, this isn’t feasible. Instead, group-based splits by fitness level are an effective compromise:

• High, moderate, and low fitness groups
• Adjusted programming to match physical readiness
• Maintains unit cohesion while managing individual risk

While group splits exist in most military settings, their execution is flawed. I’ve witnessed complex barbell lifts assigned universally, regardless of individual technical proficiency, leading to preventable injuries. Complex movements—loaded or unloaded—require proper progression and technical oversight. Without this, injuries increase, and training becomes counterproductive.

B. Task-Specific Testing

Another systemic issue is the misalignment between military fitness tests and mission demands. During my service in an artillery unit under the infantry-based 3rd Division, we were tested using outdated metrics similar to the old U.S. Army Physical Fitness Test:

• 3 km run
• Max push-ups (2 minutes)
• Max sit-ups (2 minutes)

These tests barely reflected our actual operational demands—delivering artillery shells weighing up to 66 lbs (30 kg) repeatedly under time. From a performance science perspective, tasks like lifting heavy shells require:

• Odd grip strength/endurance
• Core stability
• Rotational power

Standardized tests fail to capture these requirements. To truly prepare soldiers:

• Fitness assessments must align with specific mission demands
• Bases with different operational roles (e.g., artillery, infantry, mechanized units) need differentiated testing, much like how the U.S. Navy assesses water competency for its personnel.

This targeted approach informs trainers and reduces injury risk, while maintaining mission readiness.

Tactical Strength & Conditioning for Longevity

Tactical strength and conditioning pushes both physical and mental capacity. It involves unique stressors—like ruck marches and prolonged field operations —that civilians rarely experience.

While injuries may be inevitable in high-stress environments, intelligent programming reduces both their frequency and severity. Through:

• Fitness group splits
• Task-specific testing
• Gradual technical progression
• Load management based on readiness

We can create military training environments that maximize performance while protecting long-term health and operational effectiveness.

References

Knapik, J. J., Jones, B. H., & Darakjy, S. (2001). Injury incidence and physical fitness in U.S. Army units. Military Medicine, 166(7), 546–550. https://doi.org/10.1093/milmed/166.7.546