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Greater fatigability in knee-flexors vs. knee-extensors after a standardized fatiguing protocol.
Eur J Sport Sci. 2018 Sep; 18(8):1110-1118.EJ

Abstract

The present study aimed to investigate the effects of a standardized fatiguing protocol on central and peripheral fatigue in knee-flexors and knee-extensors. Thirteen healthy men (age: 23 ± 3 years; height: 1.78 ± 0.09 m; body-mass: 73.6 ± 9.2 kg) volunteered for the present study. Maximal voluntary contraction (MVC), Electromyography (EMG) activity, voluntary activation level (VAL) as an index of central fatigue and twitch potentiation as an index of peripheral fatigue were measured before and after the fatiguing protocol. The fatiguing protocol consisted of a 0.6 duty-cycle to exhaustion (6 s isometric contraction, 4 s recovery) at 70% MVC. After the fatiguing protocol, MVC decreased in both (Effect-size (ES) = 1.14) and knee-extensors (ES = 1.14), and EMG activity increased in both knee-flexors (ES = 2.33) and knee-extensors (ES = 1.54). Decreases in VAL occurred in knee-flexors (ES = 0.92) but not in knee-extensors (ES = 0.04). Decreases in potentiation occurred in both knee-flexors (ES = 0.84) and knee-extensors (ES = 0.58). The greater central occurrence of fatigue in knee-flexors than in knee-extensors may depend on the different muscle morphology and coupled with a greater tolerance to fatigue in knee-extensors. The present data add further insight to the complicated knee-flexors-to-knee-extensors strength relationship and the mechanisms behind the different occurrence of fatigue.

Authors+Show Affiliations

a EA4660-C3S Laboratory - Culture, Sports, Health and Society and Exercise Performance, Health, Innovation Platform , Univ. Bourgogne Franche-Comté , Besançon , France. b Department of Biomedical Sciences for Health , University of Milan , Milan , Italy.a EA4660-C3S Laboratory - Culture, Sports, Health and Society and Exercise Performance, Health, Innovation Platform , Univ. Bourgogne Franche-Comté , Besançon , France.a EA4660-C3S Laboratory - Culture, Sports, Health and Society and Exercise Performance, Health, Innovation Platform , Univ. Bourgogne Franche-Comté , Besançon , France.c EA3920-Prognostic Markers and Regulatory Factors of Heart and Vascular Diseases and Exercise Performance, Health, Innovation Platform , Univ. Bourgogne Franche-Comté , Besançon , France. d Department of Physical Training , Tomsk Polytechnic University , Tomsk , Russia.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29738677

Citation

Coratella, Giuseppe, et al. "Greater Fatigability in Knee-flexors Vs. Knee-extensors After a Standardized Fatiguing Protocol." European Journal of Sport Science, vol. 18, no. 8, 2018, pp. 1110-1118.
Coratella G, Grosprêtre S, Gimenez P, et al. Greater fatigability in knee-flexors vs. knee-extensors after a standardized fatiguing protocol. Eur J Sport Sci. 2018;18(8):1110-1118.
Coratella, G., Grosprêtre, S., Gimenez, P., & Mourot, L. (2018). Greater fatigability in knee-flexors vs. knee-extensors after a standardized fatiguing protocol. European Journal of Sport Science, 18(8), 1110-1118. https://doi.org/10.1080/17461391.2018.1469674
Coratella G, et al. Greater Fatigability in Knee-flexors Vs. Knee-extensors After a Standardized Fatiguing Protocol. Eur J Sport Sci. 2018;18(8):1110-1118. PubMed PMID: 29738677.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Greater fatigability in knee-flexors vs. knee-extensors after a standardized fatiguing protocol. AU - Coratella,Giuseppe, AU - Grosprêtre,Sidney, AU - Gimenez,Philippe, AU - Mourot,Laurent, Y1 - 2018/05/08/ PY - 2018/5/9/pubmed PY - 2018/9/6/medline PY - 2018/5/9/entrez KW - EMG activity KW - Maximal voluntary contraction KW - potentiated twitch KW - voluntary activation level SP - 1110 EP - 1118 JF - European journal of sport science JO - Eur J Sport Sci VL - 18 IS - 8 N2 - The present study aimed to investigate the effects of a standardized fatiguing protocol on central and peripheral fatigue in knee-flexors and knee-extensors. Thirteen healthy men (age: 23 ± 3 years; height: 1.78 ± 0.09 m; body-mass: 73.6 ± 9.2 kg) volunteered for the present study. Maximal voluntary contraction (MVC), Electromyography (EMG) activity, voluntary activation level (VAL) as an index of central fatigue and twitch potentiation as an index of peripheral fatigue were measured before and after the fatiguing protocol. The fatiguing protocol consisted of a 0.6 duty-cycle to exhaustion (6 s isometric contraction, 4 s recovery) at 70% MVC. After the fatiguing protocol, MVC decreased in both (Effect-size (ES) = 1.14) and knee-extensors (ES = 1.14), and EMG activity increased in both knee-flexors (ES = 2.33) and knee-extensors (ES = 1.54). Decreases in VAL occurred in knee-flexors (ES = 0.92) but not in knee-extensors (ES = 0.04). Decreases in potentiation occurred in both knee-flexors (ES = 0.84) and knee-extensors (ES = 0.58). The greater central occurrence of fatigue in knee-flexors than in knee-extensors may depend on the different muscle morphology and coupled with a greater tolerance to fatigue in knee-extensors. The present data add further insight to the complicated knee-flexors-to-knee-extensors strength relationship and the mechanisms behind the different occurrence of fatigue. SN - 1536-7290 UR - https://www.unboundmedicine.com/medline/citation/29738677/Greater_fatigability_in_knee_flexors_vs__knee_extensors_after_a_standardized_fatiguing_protocol_ L2 - https://www.tandfonline.com/doi/full/10.1080/17461391.2018.1469674 DB - PRIME DP - Unbound Medicine ER -