https://doi.org/10.14517/aosm17015 Case Report pISSN 2289-005X·eISSN 2289-0068

CrossFit-induced : a case report

Moinuddin Nadaf1, Jin Kyu Lee2, Jae-Hyuk Yang1

1Department of Orthopedic , Hanyang University Guri Hospital, Guri, 2Department of , Hanyang University Hospital, Seoul, Korea

CrossFit is a fitness regimen that has recently gained popularity in Korea. Although this training program has been shown to increase stamina and body fitness, it has also been associated with risk of exertional rhabdomyolysis. The severity of exertional rhabdomyolysis ranges from mild to life threatening situations, including acute renal failure, com- partment syndrome, hepatic dysfunction, disseminated intravascular coagulation, cardiac arrhythmia, and even death. In this report, we describe a case of exertional rhabdomyolysis after CrossFit training. We have reviewed the current literature and suggested possible preventative measures during training to minimize associated with CrossFit workouts.

Keywords: CrossFit; Rhabdomyolysis

INTRODUCTION wearier of the potential health risks, such as exertional rhabdomyolysis, of CrossFit workouts. CrossFit-induced CrossFit is a high-intensity fitness regimen, popular in exertional rhabdomyolysis should be diagnosed earlier western countries, that has recently gained popularity and appropriately managed, and preventative strategies among Koreans. The number of CrossFit gyms has in- against this condition should be implemented in the near creased in Korea. Although it has been shown to improve future. Here, we report a case of exertional rhabdomyoly- stamina and body fitness, the training program has been sis induced by CrossFit. associated with risk of , such as exercise-induced rhabdomyolysis. Exertional rhabdomyolysis is often un- CASE REPORT derdiagnosed and underreported, and very few studies concerning CrossFit-induced rhabdomyolysis have been A 33-year-old male patient presented with severe published [1,2]. on his shoulder and upper arm and with dark colored Exertional rhabdomyolsis is a serious medical condi- . The patient reported of having recently begun an tion caused by muscle damage [1,3–5]. The condition is intensive training program at a CrossFit gym. The train- characterized by muscle weakness, restricted active and ing program involved several intensive workout exercises. passive movements, severe myalgia, and dark urine. It Workout exercises would typically be three sets of 100 has a wide clinical spectrum, ranging from mild to life pushups or 3 sets of shoulder exercises, which comprise threatening clinical manifestations, including acute renal 20 alternated biceps curls, 20 shoulder presses, 20 triceps failure, compartment syndrome, hepatic dysfunction, kickbacks, 20 lateral raises, and 20 lying flies, with a 20- disseminated intravascular coagulation, cardiac arrhyth- kg dumbbell. Each set is usually completed within few mia, and even death [6,7]. minutes with a 1-minute rest interval between sets. The With the increasing popularity of CrossFit gyms, health- workout sessions are held in groups, and participants care professionals and CrossFit coaches should become are encouraged to compete with each other. The patient

Received September 8, 2017; Revised October 20, 2017; Accepted November 8, 2017 Correspondence to: Jae-Hyuk Yang, Department of Orthopedic Surgery, Hanyang University Guri Hospital, 153 Gyeongchun-ro, Arthroscopy and Guri 11923, Korea. Tel: +82-31-560-2184, Fax: +82-31-557-8781, E-mail: [email protected] Orthopedic Sports Copyright © 2018 Korean Arthroscopy Society and Korean Orthopedic Society for . All rights reserved. CC This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ AOSM by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Arthrosc Orthop Sports Med 2018;5(1):29-31 29 Moinuddin Nadaf, et al. CrossFit-induced rhabdomyolysis

stated that although he had exercised regularly he had for aggressive fluid . We administered intravenous never performed such intense training before. The pa- isotonic fluid to the patient at a rate of approximately 400 tient was not a smoker, did not take drugs, or have any mL/h initially and then titrated it to maintain a urine out- or a notable medical history. The patient was 175 put of at least 200 mL/h [8]. The patient’s renal function, cm in height and weighed 86 kg. electrolyte levels, and urine were monitored daily. Us- On physical examination of the patient, we noted that ing Tc-99m pyrophosphate, we performed scintigraphy, he had severe muscle tenderness in the shoulder and which revealed an increased uptake of the agent in the af- the upper arm. Manual muscle grading test could not be fected areas (Fig. 1). The patient’s CK level peaked (92,184 performed because the patient had severe myalgia. Find- units/L) on the 2nd day and subsequently fell to < 20,000 ings of other physical examinations, electrocardiography, units/L 4 days later. Pain and myoglobinuria resolved on and chest radiography were normal. We found that the the 5th day. The patient was discharged on the 7th day patient had a serum creatine kinase (CK) level of 85,868 after having received fluid management to prevent acute units/L (normal range, 30–300 units/L) and a muscle kidney injury. At the 3-week follow-up, we found that the and brain fraction of 0.3% (reference value, < 6%). We patient’s CK level decreased further to 327 units/L. By found that the levels of , aspartate the 1-month follow-up, the patient had returned to light aminiotransferase, and alanine aminotransferase were work and well tolerated exercise on a stationary bike. elevated to 4,750 units/L, 632 units/L, and 485 units/L, respectively. A urine analysis revealed dark brown urine, DISCUSSION 2+ occult blood, 2+ protein, and a level of 150,000 ng/mL (reference value, ≤ 10 ng/mL). Creatine CrossFit involves high-intensity exercises such as power levels and the estimated glomerular filtration rate were lifting, running, and strength movements performed within the normal range. in rapid succession, with minimal recovery time [1]. We diagnosed exertional rhabdomyolysis, and the patient Although the benefits of CrossFit are appealing, consid- was admitted and transferred to an internal department erable flexibility, balance, and strength are required to achieve the many of the workout exercises. High training volumes and short rest intervals lend participants to per- form imprecise CrossFit movements, which may lead to acute muscle injuries [2]. A few case reports have raised concerns about CrossFit exercises, such as that they can lead to rhabdomyolysis and, therefore, a clinical triad of myalgia, muscle weakness, and dark urine [1,2]. The incidence of exertional rhabdomyolysis is known to be relatively rare, occurring in 29.9 cases per 100,000 people [9,10]. The low incidence rate may be because the condition is often underreported and underdiagnosed. Rhabdomyolysis is the result of both physical and non- physical factors such as strenuous exercises, including marathon running [11], military training [12], and high intensity resistance training, medication, crushing inju- ries, and metabolic disorders [6,10]. The overarching goal of rhabdomyolysis treatment is to preserve kidney func- tion. Fluid therapy, and in some cases dialysis, should be implemented to augment and restore kidney function [10]. Fig. 1. Bone scans taken 4 hours after intravenous administration of Another characteristic feature of rhabdomyolysis is an 99mTc-methylene diphosphonate (MDP) 20mCi show increased up- elevated CK level, ranging anywhere from 1,500 to over take of the agent in the pectoralis major and biceps brachii muscles on the anterior (ANT) images (left panels) and in the triceps brachii 100,000 units/L (an approximately five-fold increase of muscles on the posterior (POST) images (right panels). the normal value). Therefore, an elevated CK level is used

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as a diagnostic marker of rhabdomyolysis. muscle strength is built; 2) incorporate around 8 to 10 Some complications associated with rhabdomyolysis, exercises into the program, covering the major muscle including acute renal failure, compartment syndrome, groups (the upper body, the lower body and the trunk), and disseminated intravascular coagulation, can be life per training program; 3) perform 1 to 3 sets per exercise; threatening [6,7]. Acute renal injury occurs in approxi- 4) do 8 to 12 repetitions per set; 5) take at least 2-minute mately a third of patients with rhabdomyolysis [13]; the breaks between sets; 6) work out 2 to 3 days per week and acute injury is attributable to a direct renal injury result- on non-consecutive days; and 7) increase the duration, ing from an accumulation of myoglobin. Aggressive fluid the intensity, and the number of sets, repetition, and days replacement and dialysis should be immediately per- of the workout and decrease break time gradually. formed if the patient with rhabdomyolysis is suspected of In conclusion, intensive resistance training during Cross- an acute renal failure. Here, we did not observe any seri- Fit may cause injuries such as exertional rhabdomyolysis ous complications besides a marked elevation in serum in not only the trainers involved but also the trainees. CK levels and myoglobin level in urine. Therefore, they should be aware of the risks of exces- One of the ways to minimize the prevalence of rhab- sive CrossFit training and medical professionals should domyolysis may be to give advice such as “to start low attempt to diagnose and treat the condition in a timely and go slow” to CrossFit trainees [14,15]. For example, manner. the session duration, the number of repetitions or sets, and the intensity of the training are all factors that may CONFLICT OF INTEREST be controlled at the beginning and gradually increased. The following guidelines are currently recommended for No potential conflict of interest relevant to this article was beginners: 1) initially carry load weighing 60% to 70% of reported. the person’s one-repetition maximum, until sufficient

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