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Are high-intensity training programs safe and effective?

From the Field

Are high intensity programs safe and effective? Is there anything I should watch out for?

HPRC's Answer

High-intensity training programs


Extreme Conditioning Programs (ECPs) are aggressive exercise workouts that are metabolically and physically demanding. Many of them address a wide range of occupational Warfighter fitness requirements and are thus popular in the military. However, many also include elements that violate established fitness principles of safety and effectiveness. ECPs should be undertaken with caution, and more research is needed to determine potential benefits and risks.


The Department of Defense (DoD) and American College of Sports Medicine (ACSM) convened a workshop at the Uniformed Services University, Bethesda, Maryland to address the issue of high-intensity training (HIT) programs. During this session, scientists agreed that it would be more appropriate to refer to HIT programs as Extreme Conditioning Programs (ECPs). Click here to read the executive summary of the workshop.

Myths and Claims

ECPs and their followers claim that these programs are safe, science-based, and able to produce a balanced physique that can perform across a number of occupational demands.


Participants are often encouraged to exercise until they “puke.” Yet many military physicians have cited anecdotal reports of a high injury rate with these programs. Many individuals may not have a sufficient level of fitness to engage in such high-intensity exercise without considerable risk of injury. The fact is that no published data exist that compare these programs to other high-intensity activities such as running and basketball, which are among the leading causes of musculoskeletal injuries in military personnel.

ECPs such as CrossFit, P90X, Insanity, Gym Jones, and PT Pyramid are multi-dimensional programs that use various training methods: repeated body weight exercises, resistance training with barbells and kettlebells, explosive movements, sprints, and flexibility training. This variety prevents boredom and targets an area of unmet training needs among Warfighters. Individuals often find these programs challenging, motivating, and exciting. Many testify that they have never been in better shape.

On the other hand, certain aspects of ECPs violate well-established safety and efficacy principles. This tendency—coupled with inadequate recovery time—promotes fatigue, a greater perceived exertion during the activity, and may possibly lead to overtraining consequences. When these programs are performed in military group settings, the less fit individuals can easily overreach their physical capacity and become injured. These programs are not always balanced to meet all training needs.


Since the positive aspects of ECPs have been recognized, and since these programs appear to meet a perceived or actual unfulfilled training need, individuals and military units using them should proceed with caution. Research is needed to determine risk versus benefit of these programs, and modifications are needed to accommodate less fit individuals and prevent injury.