Creating generalized adaptation and aerobic conditioning may have its place in the general population of untrained to moderately trained non-competitive individuals provided the risk remains low.
But it has no place in the sport-specific world of athletic training.
I would be surprised to hear any professional athlete’s coach say that they plan “workouts of the day” which have no sequence nor progression under an annual training program, macrocycle, or even a microcycle that’s designed to achieve peak athletic performance.
The importance of training specificity cannot be overemphasized for high-level athletes. Generalization only goes so far in developing top-level sport skills and efficiency. Too often, coaches neglect to research what methods are best for optimum training benefits for an individual athlete. Instead they operate traditional conditioning programs that serve an entire team as a whole.
General training creates general athleticism and average athletes in my opinion. In this article, I challenge CrossFit’s claim that it’s a “survival of the fittest” sport. I rest my case on the fact that the world’s most elite athletes across all professional sports train by the “survival of the smartest” theory to preserve their longevity in sport and maximize peak performance via specifically calculated and cyclical, periodized programming.
Assigning high-volume repetitions and speed to technically demanding exercises opposes USA Weightlifting’s (USAW) recommendation to keep “repetitions to three or less on technical exercises [Olympic movements] and five or less for strength exercises (e.g. squats), and never continue repetitions if form is breaking down,” (Mullins, 2015).
Assigning fast high-volume reps to technically demanding exercises opposes USAW, NSCA guidelines.
CrossFit’s entire foundation is based on a total-body fatigue, forced-adaptation model, risking form breakdown and injury with every passing repetition. The National Strength & Conditioning Association (NSCA) aligns with the USAW philosophy, and stresses the importance of exercise order for maximal adaptation gains and the insurance of safety (Mullins, 2015):
“Power exercises require the highest level of skill and concentration of all the exercises and are most affected by fatigue. Athletes who become fatigued are prone to using poor technique and consequently are at higher risk of injury. The explosive movements and extensive muscular involvement of power exercises also result in a significant energy expenditure. This is another reason to have athletes perform such exercises first, while they are still metabolically fresh.”
This rule is ignored in most CrossFit programs.
High-repetition power and strength exercises are interspersed with high-volume multi-joint movements which ultimately lead to the exhaustion of all metabolic systems. The body responds with generalized fatigue and poor recovery and, accordingly, generalized and incomplete adaptation between workouts.
Going forward, this company’s mission should emphasize educating its athletes on the proper execution of movement as well as the risks involved when undertaking this inherently intense form of activity.
Some CrossFit facilities are run by well-educated exercise science professionals who make an effort to ensure all participants are practicing safe technique and sound progressions with individualized program design. One such individual is Dr. Mike Young, Director of Performance and Research with Athletic Lab in Cary, NC. When incorporating CrossFit programming into his Sports Performance and Athletic Development facility, he takes the following approach:
“I look at health on a continuum with diseased state being on one side, healthy being somewhere in the middle, fit being somewhere beyond that and performance oriented on the far side of the continuum. Generally speaking, I’d say CrossFit is best for people in the middle. I don’t think it’s appropriate for people who are not yet ready for intense training. Likewise, it’s not appropriate for the more specific training that CrossFit, by its very nature, does not provide.”
It’s one thing to teach a skill, but it’s an entirely different undertaking to teach the skill and have the ability to explain why this skill is applicable in a performance capacity and how it fits into an athlete’s long-term progression. If one cannot back up a workout or an exercise on a physiologically sound basis for future adaptation and progression, it has no business being executed.
General adaptation and aerobic conditioning programs have no place in sport-specific training.
In the sport-specific world of athletic training, Dr. Young states:
“When training for sport, I recommend training progress from general to specific over the course of a training program. Likewise, I generally suggest that intensities start lower and progressively increase over the course of the season. Finally, I like to see volume operate inversely to intensity over that time. So intensity and volume should rarely, if ever, be high concurrently. CrossFit has the potential to violate all of these recommendations.”
CrossFit’s long-term benefits are under researched. Several studies, however, have found there are potential benefits to aerobic capacity and body composition from this type of high-intensity functional power training.
High-intensity interval training attracts individuals looking to improve their fitness levels with minimal time commitment. Typically, the workouts take a very short amount of time, averaging between 5 to 20 minutes, and reap maximal caloric burn due to the continuous nature of the workload, relative intensity, and minimal rest periods.
In some workouts, the goal is to achieve as many rounds or repetitions as possible before the allotted time is up. Other workouts focus on the best time to completion of a given set of exercise rounds. A combination of power and Olympic lifts, cardio activity, gymnastics, and other body weight movements is used to stimulate positive adaptation of maximum aerobic capacity and improvement in body composition.
Researchers in one study had participants follow a 10-week CrossFit-based high-intensity power training (HIPT) program of traditional power and Olympic lifts. Specific exercises included squats, deadlifts, cleans, snatches, and overhead presses performed in a nontraditional fashion; participants completed the designated number of repetitions as quickly as possible (Smith, Sommer, Starkoff, & Devor, 2013).
After HIPT training, body fat reduced by 3.7% among all individuals, both males and females. Oxygen consumption relative to body weight increased in all participants with a 13.6% and 11.8% improvement in VO2 max for men and women, respectively. This was independent of the changes in body mass, which are often attributed to improvements in oxygen capacity.
With more than 10,000 CrossFit gyms (boxes) throughout the country, intense scrutiny should be placed on this company’s mission and training principles to decipher whether this is an efficacious and safe form of athletic conditioning.
Any emerging form of exercise or diet should be challenged using evidence-based practices to properly validate that the program is safe and effective for the long-term health and well-being of all participants. Long-term is the key word here.
In a review of the pros and cons of extreme conditioning programs such as CrossFit, a 2013 survey asked CrossFit participants to disclose any injuries that had prevented them from working, training, or competing over the past 19 months (Knapik, 2015). The 132 respondents averaged 5.3 hours a week of exercise during this time, and 74% claimed to have sustained an injury during that time, with 7% having an injury which required surgery. The most common injuries were to the shoulder (32%), spine (28%), and arm (20%).
Others reported carotid artery dissection (CAD) and exertional rhabdomyolysis related to CrossFit activity. The four CAD cases were attributed to lifting significantly more weight than previously lifted (20% more) and/or performing exercises with rapid twisting movements.
CAD can result in a partial blockage of the carotid artery, a partial tear in the vessel wall resulting in a hematoma, or a total rupture and subsequent aneurysm. The goal of treatment is to reduce the neurologic deficits and stabilize blood flow.
Repetitive eccentric contractions produce the muscle damage leading to exertional rhabdomyolysis (Su, 2008). Extreme muscle breakdown causes muscle enzymes and electrolytes to leak, including creatine kinase, lactate dehydrogenase, and myoglobin, and potassium.
When myoglobin levels in the blood exceed 3mg/L, it spills into the urine (myoglobinuria) and produces a tea or cola coloration. Myoglobin damages renal tubules, which can lead to tubular necrosis. If renal blood flow is further limited by high exertion levels and dehydration, the kidneys become less capable of clearing the muscle breakdown products which can lead to fatal complications (Su, 2008).
The very nature of CrossFit workouts brings an increased likelihood for these overexertion injuries to occur.
A similar survey using CrossFit’s main website included 386 participants who met the inclusion criteria for CrossFit participation (Weisenthal et al., 2014). Data from the study concluded that injury rate during the previous six months was 19.4% of total participants who experienced at least one injury; males were injured more frequently than females. Reported injuries were fewer among individuals working with a trainer. And females had a lower incidence rate, likely because they sought a coach before training.
Shoulder injuries occurred the most during gymnastic movements, and the lower back was most often injured while power lifting. These participants had no discomfort before performing these movements.
High-risk should not be confused with ineffective since most exercises provide some benefits, although the aim of exercise should always be to maximize benefits and minimize risks (Mullins, 2015).
Two very high-risk exercises commonly performed in CrossFit boxes are unassisted pistol squats and kipping pullups, which are rarely executed with proper technique.
In the pistol squat, the lordotic curve of the lumbar spine should be maintained, the knee should track over the toes with virtually no mediolateral shift, and the heel should remain in contact with the ground. Rounding the back is a compensatory mechanism to achieve depth and places unnecessary strain on the lower back.
Kipping pullups hyperextend the lumbar spine, unlike traditional pullups which allow the spine to stay neutral. Hyperextension of the spine has long been contraindicated by medical professionals due to the high potential for injuring the spinal discs, nerves, and joints.
With a nearly 20% injury rate, however, the jury is still out about whether the risk-benefit ratio is in an athlete’s favor. Similar rates of injury are seen in gymnastic and power and Olympic lifting sports.
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- Knapik, J. J. (2015). “Extreme Conditioning Programs: Potential Benefits and Potential Risks.” Journal Of Special Operations Medicine: A Peer Reviewed Journal For SOF Medical Professionals, 15(3), 108-113.
- Mullins, N. (2015). “CrossFit: Remember What You Have Learned; Apply What You Know.” Journal Of Exercise Physiologyonline, 18(6), 32-44.
- Smith, M. M., Sommer, A. J., Starkoff, B. E., & Devor, S. T. (2013). “Crossfit-Based High-Intensity Power Training Improves Maximal Aerobic Fitness and Body Composition.” Journal of Strength and Conditioning Research, 27(11), 3159- 3172. doi: 10.1519/JSC.0b013e318289e59f.
- Su, J. (2008). “Exertional Rhabdomyolysis.” International Journal of Athletic Therapy and Training, 13(5), 20-22. doi: 10.1123/att.13.5.20.
- Weisenthal, B. M., Beck, C. A., Maloney, M. D., DeHaven, K. E., & Giordano, B. D. (2014). “Injury Rate and Patterns Among CrossFit Athletes.” Orthopaedic Journal of Sports Medicine, 2(4), 2325967114531177. doi: 10.1177/2325967114531177.