Bergeron, M.F., et al. 2011. Consortium for Health and Military Performance and American College of Sports Medicine consensus paper on extreme conditioning programs in military personnel. Current Sports Medicine Reports, 10 (6), 383–89.

Introduction: What Is Extreme Conditioning?
Extreme conditioning programs (ECPs) boast vastly improved fitness in relatively short periods of time, which appeals to a cross-section of the U.S. civilian and military populations. Yet many health professionals fear that these high-powered, widely marketed programs increase the risk of musculoskeletal injuries.

Michael Bergeron, PhD, and colleagues summarized the controversy over ECPs in their 2011 paper. While their report focuses on issues central to preparing U.S. soldiers for combat missions, it provides broad guidance to fitness professionals who are participating in or leading ECPs.

The Appeal of Extreme Conditioning
Some ECPs provide the convenience of working out in settings other than a gym, an enticing attraction for people seeking training opportunities that do not involve joining a fitness facility. Furthermore, many soldiers training for high-intensity exertion on the battlefield have joined the extreme-conditioning fitness craze.

Responding to concerns about the hazards of ECPs, in 2010 the delegates from the American College of Sports Medicine, the Consortium for Health and Military Performance, and the Department of Defense convened to develop a consensus platform of evidence-based guidelines for these programs (Bergeron et al. 2011). The group defined extreme conditioning programs as “high-volume aggressive training workouts that use a variety of high-intensity exercises and often timed maximal number of repetitions with short rest periods between sets.” These programs are multifaceted, incorporating aspects of circuit training, resistance training and high-intensity interval training, along with various body weight exercises. Exercise professionals use these same training protocols (albeit safely and effectively) with clients every day.

The intensity and high metabolic and physical demand of ECPs are central to the controversy. Bergeron and colleagues note that primary physicians and rehabilitation providers have identified an emerging problem of disproportionate musculoskeletal injury risk, particularly for novice ECP participants.

Military professionals who participated in this report are concerned that U.S. soldiers believe extreme conditioning workouts are essential for battlefield preparedness. In fact, for some members of the active-duty military, ECPs are causing musculoskeletal injuries that cut down duty time and decrease military readiness (AFHSC 2013).

To educate clients and exercise enthusiasts who might be inspired by the example of our soldiers training with ECPs, fitness professionals must be able to identify the benefits and risks of these programs.

What Are the Benefits of Extreme Conditioning Programs?
Many ECPs are designed to employ high-intensity metabolic conditioning exercises, which Bergeron et al. (2011) describe as exercises that “impose a moderate to high demand on the cardiovascular system and energy metabolism of the active muscle fibers to meet with the muscles’ repeated high-energy requirements.” Observed benefits of using these programs include reduced body fat, increased local muscular endurance and increased cardiovascular capacity (Bergeron et al. 2011).

Another focus of extreme conditioning is functional fitness. To this end, ECPs concentrate on a person’s ability to perform whole-body (or multijoint) movements repeatedly under highly fatiguing conditions (Bergeron et al. 2011). The multifaceted nature of ECPs leads participants to believe they are getting benefits beyond those gained through typical physical fitness programs, Bergeron and colleagues explain. And many soldiers believe that ECPs not only increase combat readiness (as noted) but also enhance camaraderie and teamwork. These beliefs heighten the appeal of individual and/or group ECP sessions.

What Are the Risks of Extreme Conditioning?
Bergeron and colleagues say certain characteristics of extreme conditioning workouts appear to disregard current standards for developing muscular fitness. For instance, repetitive performance of maximal timed repetitions—with insufficient rest periods between sets—may readily lead to
• premature fatigue,
• elevated oxidative stress (inability of the body to remove biological products that lead to cell damage),
• increased risk of musculoskeletal strain and injury, and
• impaired exercise technique.

Bergeron and colleagues add that extremely challenging training regimes may lead to overuse injuries, overtraining and overreaching (going beyond normal progressive overload training parameters).

Injury risk also increases when exercise sessions become competitive. For example, military personnel and exercise enthusiasts in a class often seek peer approval by attempting to keep up with others who may be fitter and stronger. In recreational sports conditioning, where training as a team is very important, this same mindset happens. Individuals are often encouraged to push themselves unknowingly to excess, leading to a greater potential for injury. In a team setting, it becomes difficult to scale back.

Although individual pacing and progression are essential for proper fitness development, respect for these guidelines is often perceived as a sign of weakness (Bergeron et al. 2011). The overreaching phenomenon may be more common in entry-level participants in ECPs.

Are There Other Special Concerns With Extreme Conditioning Programs?
Certain factors related to medical status and health warrant reduced physical activity and should preclude ECP participation among the following:
• people who have had a traumatic brain injury (including concussion)
• anyone who has suffered a recent musculoskeletal injury
• those with a predisposing medical condition such as sickle cell trait (Bergeron et al. 2011)

People with sickle cell trait are much more vulnerable to exertional rhabdomyolysis, a response to excessive, repetitive exercise in which the muscle cell membranes break down and release myoglobin and other intracellular proteins into the blood, causing kidney damage and potential kidney failure.

Other notable clinical conditions that suggest caution with ECPs include hypertension; recent bouts of heat-related illness (heat cramps, heat exhaustion, heat stroke or hyponatremia—very low blood levels of sodium, associated with dehydration); and previous episodes of exertional rhabdomyolysis (including those occurring in people without sickle cell trait) (Bergeron et al. 2011).

Some common prescribed medications (or often combinations of medications) may also impair balance and worsen exercise performance in an ECP. These medications include antidepressants, antianxiety drugs, antihistamines prescribed to relieve allergy symptoms, blood pressure and other heart medications, pain relievers and sleep aids (Harvard Health Publications 2013). According to Bergeron, sleep deprivation, recent illness and recurring headaches would likewise be alerts to suspend or reduce participation in ECPs.

Recommendations to Improve ECP Safety
Reducing injury risk and improving the implementation of extreme conditioning programs are of paramount importance. Among Bergeron and colleagues’ recommendations for safe ECPs:
• Conduct careful inspections of designated exercise equipment and areas.
• Introduce ECPs gradually with a planned, stepwise progression for exercise intensity and duration, particularly for beginning students with low fitness levels.
• Base individualized supplemental conditioning programs on fitness, training goals and job-specific functional needs and demands.
• Plan regularly scheduled days of reduced or no supplemental conditioning, especially in more active populations such as the military and recreational athletes.
• Watch for preworkout use of caffeine and products containing substantial levels of caffeine, such as popular energy drinks. Use should be discouraged, as caffeine can easily mask fatigue, leading to overreaching and overexertion.

Other recommendations for ECP implementation are shown in Figure 1.

Final Thoughts
With the growing interest in extreme conditioning workouts, it is essential that exercise professionals know the potential risks of participation in these programs and educate their clients and students appropriately. ECPs can be effective in enhancing certain aspects of physical fitness, but they need to target the fitness level, conditioning and training needs of the individual participants (Bergeron et al. 2011).

Bergeron and colleagues suggest that ECPs may actually be recommended as a supplement to an incremental, well-rounded exercise regimen. However, those who engage in ECPs should pay particular attention to their personal limitations before and during participation. As with other forms of training, risk factors should be considered in advance, and the principle of progression should be employed to ensure a safe workout. Last, and perhaps most impressively, Bergeron and consortium colleagues conclude their report on ECP use among soldiers by saying that “qualified fitness trainers” are “better equipped to more appropriately design, individualize, implement and oversee an effective progressive and periodic program.”

Justin D. Baca is an undergraduate in the exercise science program at the University of New Mexico, Albuquerque. He plans to pursue a doctoral degree in physical therapy.

Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico, Albuquerque, where he has won the Outstanding Teacher of the Year award. He was honored with the Can-Fit-Pro Lifetime Achievement Award in 2008 and received the 2010 Aquatic Exercise Association Global Award.

Figure 1. Practical Suggestions for Successful ECP Implementation


AFHSC (Armed Forces Health Surveillance Center). 2013. Update: Exertional rhabdomyolysis, active component, U.S. Armed Forces 2008-2012. Medical Surveillance Monthly Report, 20 (3), 21-24.
Harvard Health Publications. 2013. How medications can affect your balance. Harvard Medical School.; retrieved June 16, 2013.

Justin D. Baca

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