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Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
Online ISSN 1827-1928
Scott N. DRUM 1, Bryanne BELLOVARY 1, 2, Randall JENSEN 1, Maggie MOORE 1, Lars DONATH 1, 3
1 Northern Michigan University, School of Health and Human Performance, Marquette, MI, USA; 2 Wayne State University, Canton, MI; 3 Department of Sport, Exercise and Health, University of Basel, Switzerland
BACKGROUND: CrossFit® is considered an intense and extreme conditioning program (ECP) that can cause overtraining and injury. Exertional Rhabdomyolysis (ER) - breakdown of muscle tissue - after ECP has been reported in CrossFit® and might be linked to comparatively high rates of subjectively perceived exertion levels. Therefore, the present study aimed at (a) recording symptoms of post-exercise physical dysfunction (e.g., excessive muscle soreness, shortness of breath) following CrossFit® and (b) ratings of perceived exertion (RPE) during CrossFit® compared with training according to the American College of Sports Medicine (ACSM) guidelines.
METHODS: A validated questionnaire was completed by 101 CrossFit® (age: 35±8 years; weight: 79±16 kg) and 56 ACSM (age: 35±10 years; weight: 75±27 kg) participants.
RESULTS: CrossFit® and ACSM groups, respectively, reported significantly different RPE levels of 7.3±1.7 and 5.5±1.4 (p ≤ 0.001) and amounts of hard days per week of 4.0 ± 1.1 and 3.5 ± 1.4 (p = 0.04). The five most frequent and hardest ECP workouts of the day (WODs) were Fran (47), Murph (27), Fight Gone Bad (10), Helen (9) and Filthy 50 (9). Presence of severe post-exercise symptoms was notably higher in CrossFit® for excessive fatigue (42 vs. 8; p<0.001), muscle soreness (96 vs. 48; p=0.04), muscle swelling (19 vs. 4; p=0.048), shortness of breath (13 vs. 1; p=0.02), muscle pain to touch (31 vs. 4; p=0.001), and limited muscle movement during workout (37 vs. 9; p=0.007).
CONCLUSION: CrossFit® leads to “very hard” perceived exertion causing detrimental post-exercise effects on muscle and ventilatory function in experienced athletes. Improved training progression with adequate recovery schedules are needed to prevent severe muscle injury, such as ER.