ORIGINAL ARTICLE  EPIDEMIOLOGY AND CLINICAL MEDICINE 

The Journal of Sports Medicine and Physical Fitness 2017 May;57(5):604-9

DOI: 10.23736/S0022-4707.16.06243-5

Copyright © 2016 EDIZIONI MINERVA MEDICA

language: English

Perceived demands and postexercise physical dysfunction in CrossFit® compared to an ACSM based training session

Scott N. DRUM ¹, Bryanne N. BELLOVARY ^{1, 2}, Randall L. JENSEN ¹, Maggy T. MOORE ¹, Lars DONATH ^{1, 3} ✉

¹ Exercise Science Laboratory, School of Health and Human Performance, Northern Michigan University, Marquette, MI, USA; ² Wayne State University, Canton, MI, USA; ³ Department of Sport, Exercise and Health, University of Basel, 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 recording symptoms of postexercise physical dysfunction (e.g., excessive muscle soreness, shortness of breath) following CrossFit® and 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).
CONCLUSIONS: 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.

KEY WORDS: High-intensity interval training - Physical exertion - Resistance training – Rhabdomyolysis