ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2020 September;60(9):1216-22

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 ALMEIDA SOUZA ¹, Bianca MIARKA ², Ranele CARDOSO ³, Maurício BADARÓ ⁴, Ciro BRITO ⁵, Alexandre W. CARVALHO 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 Odontology Federal University of Juiz de Fora, Juiz de Fora, Brazil; ⁴ Department of Odontology, Federal University of Santa Catarina, Florianópolis, Brazil; ⁵ Department of Physical Education, Federal University of Juiz de Fora, Juiz de Fora, Brazil

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 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: Fatigue; Electromyography; Athletes; Muscle strength, Athletic performance