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The Journal of Sports Medicine and Physical Fitness 2020 May 13

DOI: 10.23736/S0022-4707.20.10845-4

Copyright © 2020 EDIZIONI MINERVA MEDICA

language: English

Interquartile differences in biomechanical parameters in CrossFit® athletes during deep squats with submaximal load until fatigue

Isabella C. FERREIRA 1, Matheus A. SOUZA 1, Bianca MIARKA 2, Ranele CARDOSO 5, Maurício BADARÓ 4, Ciro BRITO 3, Alexandre W. BARBOSA 1

1 Department of Physical Therapy, Federal University of Juiz de Fora, Juiz de Fora, Brazil; 2 Department of Physical Education, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; 3 Department of Physical Education, Federal University of Juiz de Fora, Juiz de Fora, Brazil; 4 Department of Odontology, Federal University of Santa Catarina, Santa Catarina, Brazil; 5 Department of Odontology Federal University of Juiz de Fora, Juiz de Fora, Brazil


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BACKGROUND: CrossFit® exercises are demanding and require high power outputs sustained over time, therefore the daily workouts (WOD) could provoke considerable fatigue and lead to injury in a subsequent exercise session. To improve performance and prevent injury, the effect of pacing strategies has to be studied, by observing how fatigue modifies movement biodynamics until muscle failure. Thus, the present study aimed to analyze the interquartile differences in biomechanical parameters in CrossFit® athletes during deep squats with submaximal load until fatigue.
METHODS: This is a comparative and descriptive applied research study using electromyographic analysis. Twenty (n=20) CrossFit® competition athletes participated in this study (age=27±6 years; training experience=14.4±7.7 months; weight=80±11 kg; height=175±7 cm; BMI=26±3 kg/m2).
RESULTS: The mean time until fatigue was 14±8 minutes. Pairwise comparisons confirmed fatigue by using the lactate results (pre=1.80 mg/dL, post=12.60 mg/dL; p=0.0001). Significant differences were noted among quartiles (Pillai’s trace F=3.99; p=0.001) on the composite variable.
CONCLUSIONS: The results supported the hypothesis of self- regulation and showed higher velocity associated with higher maximal power. Concentric muscular recruitment was associated to the detriment of the eccentric phase during progressive fatigue. Coaches and athletes can apply the results of the present study when establishing WOD strategies during training and competition.


KEY WORDS: CrossFit; Biomechanics; Fatigue; Deep squat; Electromyography

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