Beyond the intensity: A systematic review of rhabdomyolysis following high-intensity functional training

Objective: Rhabdomyolysis is a dangerous medical condition with potentially serious or fatal outcomes. It has been notably linked with high-intensity functional training (HIFT), a highly popular form of exercise. Methods: This research aimed to analyze reported cases of exertional rhabdomyolysis (ER) resulting from HIFT through a systematic review following the PRISMA guidelines. Results: A total of 26 studies encompassing 63 cases were included. Commonly observed symptoms include muscle pain, swelling, exceptionally high creatine kinase levels, and dark urine, with creatine kinase levels ranging from 7,816 to 232,579 U/L. The predominantly affected muscles were in the upper body, especially the arms. Elevated creatine kinase levels, severe muscle pain, and swelling emerged as the most reliable ER indicators. The patient age range was predominantly 20-40 years. Notably, over one-third of the cases analyzed were of low quality. Conclusion: Our findings suggest HIFT may pose a higher risk for ER compared to most other common sporting activities. (c) 2024 Consell Catal & agrave; de l'Esport. Published by Elsevier Espa & ntilde;a, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).