Mitigate Client’s Risk of Rhabdomyolysis
Rhabdomyolysis, while rare, can develop from high intensity or high-volume exercise, including CrossFit or any other process that damages muscle cells. Rhabdomyolysis (often simply referred to as “rhabdo”) is a medical condition that may arise from breakdown of muscle tissue and release of the muscle cells’ contents into the bloodstream. This process can damage the kidneys and may lead to renal failure or death in rare cases. Rhabdo is diagnosed when a patient with an appropriate history has an elevated level of another molecule, creatine kinase, also known as CK or CPK. CPK is easier to measure in the blood than myoglobin and is generally used as a marker for rhabdo, even though it is the myoglobin that does the damage.
Treatment consists of generous amounts of intravenous fluids to dilute and flush the myoglobin through the kidneys. In the worst cases, patients may need dialysis while the kidneys recover. Death, though rare, can result when the kidney failure causes imbalances in the usual electrolytes, which may cause cardiac arrhythmias. Most patients make a complete recovery after being rehydrated with IV fluids over anywhere from several hours to a week or so, depending on the severity.
There are a few ways a CrossFit trainer can protect athletes from rhabdomyolysis:
Following the mechanics-consistency-intensity charter is to best prepare the athlete for long-term success, but it is also a way to mitigate the potential of developing rhabdomyolysis (and other injuries). Slow and gradual increases in intensity and volume allow the body to acclimate to high-intensity and higher-volume exercise. Even athletes who quickly demonstrate sound mechanics still need a gradual increase in intensity and volume. When working with new athletes, trainers should focus on using modest loads, reducing volume, and coaching the athlete on technique. At affiliates where there are “elements” or “on-ramp” classes that last a couple of weeks, athletes should still be heavily scaled beyond this introductory period to ensure adequate time to acclimate to CrossFit training. If there are no separate classes for beginners, treat the workouts as technique sessions for newer athletes–focus on their mechanics rather than speed or load. There is no set protocol for how quickly to increase intensity, but it is wise to err on the side of caution and work toward long-term fitness. Multiple months at scaled loads and volumes are well within a normal timeframe for even the best athletes, with gradual increases in intensity implemented after that. Trainers need to frequently check in with athletes to determine how the previous dose of exercise affected them. Although intensity is a significant part of CrossFit, each athlete has his or her entire life to continue to improve fitness and tolerance for intensity.
The second way to mitigate the risk of rhabdomyolysis is to know the movements associated with a higher rate of incidence. Beginner athletes should keep “negatives” (movements which prolong the eccentric phase) to a minimum. Although negatives can be an effective way to increase strength, they should not be used in high volumes with beginners. Athletes may increase the volume of negatives gradually over time.
While the eccentric phase of movements cannot and should not be avoided, there are movements in which people are more likely to prolong the eccentric phase. In CrossFit, these tend to be jumping pull-ups and full range-of-motion Glute-Ham Developer (GHD) sit-ups. In the jumping pull-up, the athlete should not prolong the descent but should instead immediately drop to an extended-arm position once the chin has cleared the bar, absorbing the impact with the legs. Similarly, in the full range-of-motion GHD sit-up, newer athletes should use fewer repetitions and potentially a shortened range of motion until capacity is developed. It is also prudent for trainers to scale the number of repetitions and the range of motion for athletes who do not routinely use GHD sit-ups regardless of their CrossFit experience. There are no exact rules for total volume, but beginners and new CrossFit athletes (and even advanced CrossFitters who have not been routinely using the GHD) should start with relatively low repetitions of the partialrange-of-motion GHD sit-up (i.e., to parallel) and gradually increase from there with consistent exposure.
Progressive scaling–the practice of continually adjusting the difficulty of a workout so that an exhausted athlete can keep moving–must be avoided with the beginner or even intermediate athlete. Allow these athletes to stop and take rest as needed to complete the workout. An example may be if the trainer keeps lowering the load, so the athlete does not have to stop completing reps (e.g., 135-lb. barbell for thrusters dropped to 115 to 95 to 65 to 45 across the workout duration). Progressive scaling may be used, but it must be applied very cautiously even with the most advanced of athletes.
It is also wise to educate athletes about the potential risk for rhabdomyolysis, strategies to reduce the risk and the symptoms. This will help them understand the rationale for scaling their workouts, especially when they are zealous to perform a workout “as prescribed” (“Rx’d”).
Alcohol and drug use increase the risk of rhabdomyolysis, and athletes should avoid heavy drinking, especially in proximity to training. Certain medications, including statins (cholesterol-lowering agents), increase the risk of rhabdomyolysis.
Symptoms of rhabdomyolysis include severe generalized muscle pain, nausea and vomiting, abdominal cramping, and, in severe cases, dark-red or cola-coloured urine. The discoloration of the urine comes from the muscle’s myoglobin, which is the same molecule that gives red meat its color. If these symptoms appear following a workout (or at any time with regard to dark-red urine), the athlete should seek medical attention immediately.
The athletes at highest risk seem to be those with a reasonable baseline level of fitness obtained through some non-CrossFit training, those who are returning to CrossFit after a layoff, or even experienced CrossFitters who reach volume or intensity significantly outside their established “norm.” These athletes have sufficient muscle mass and conditioning to create enough intensity to hurt themselves. Generally, the most deconditioned seem to be at less risk (but not zero). It is suspected they do not have enough muscle mass or the capacity to generate high levels of intensity. This being said, athletes and trainers must properly scale and focus on mechanics with every client regardless of current capacity.