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New CrossFit participants may be a higher risk for rhabdomyolysis

OCTOBER 23, 2018
Clinical Congress Daily Highlights, Tuesday First Edition

CrossFit, a type of high-intensity workout that can yield impressive fitness gains, poses significant risks to participants that include exercise-induced rhabdomyolysis, according to a new study led by Ben Hopkins, BS, Northwestern Feinberg School of Medicine, Chicago.

CrossFit has become a $4 billion-a-year industry, with more than 11,000 gyms or “black boxes” offering CrossFit across the country, Hopkins reported. “CrossFit exercise training has developed a cult-like following,” he said.

Recently documented cases of rhabdomyolysis after CrossFit participation have increasingly concerned physicians and participants alike, with some resulting from as few as one exercise session, Hopkins said. These reports led Hopkins and his colleagues to attempt a quantitative assessment of exercise-induced rhabdomyolysis after CrossFit participation.

The researchers surveyed all patients who presented to the main hospital at a major academic center complaining of an injury sustained while performing CrossFit between June 2010 and June 2016. The cases were identified by the key phrases ‘CrossFit’ , ‘crossfit’ , ‘Crossfit’ or ‘cross fit’ through the institution’s Electronic Data Warehouse (EDW), a clinical data repository.

The researchers found 523 patients who incurred injuries associated with CrossFit activities; 81.5 percent of the injuries were musculoskeletal, according to the research.

The search found that 11 of the patients, or 2.1 percent, ultimately received a diagnosis of rhabdomyolysis. The average age of the rhabdomyolysis patients was 34.9 years; 81.8 percent were male, the average BMI was 24.2, and the average experience level was beginner (54.5 percent).

The most common presenting symptom among rhabdomyolysis cases was dark urine (90.9 percent), followed by upper extremity pain (54.5 percent). The average symptom duration was 2.9 days with 81.8 percent of patients presenting initially to the emergency department. The average hospital stay was roughly 2.9 days, and patients had an average of 1.44 clinical follow-up visits.

“Beginners should not jump into intense exercise too quickly,” Hopkins concluded.

Further study is needed to raise awareness of this issue and further quantify risk factors such as inadequate experience, which may promote injury during participation, Hopkins said.

The Scientific Forum presentation, CrossFit and Rhabdomyolysis: A Case Series of 11 Patients Presenting at a Single Academic Institution, was held October 23 at the 2018 Clinical Congress of the American College of Surgeons in Boston.  Program, webcast and audio information is available online at

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