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Neuromuscular fatigue following isometric contractions with similar torque time integral.
Int J Sports Med. 2015 Jan; 36(1):35-40.IJ

Abstract

Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25%, 50%, and 75% of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5±33.4 s, 35.1±16.8 s and 24.8±12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately after the sustained contractions. EMG activity of the vastus lateralis (VL) and -rectus femoris (RF) muscles was recorded during the sustained contractions. MVC torque reduction was similar in the 3 conditions after the exercise (-23.4±2.7%). VAL decreased significantly in a similar extent (-3.1±1.3%) after the 3 sustained contractions. Potentiated doublet amplitude was similarly reduced in the 3 conditions (-19.7±1.5%), but VL and RF M-wave amplitudes remained unchanged. EMG activity of VL and RF muscles increased in the same extent during the 3 contractions (VL: 54.5±40.4%; RF: 53.1±48.7%). These results suggest that central and peripheral alterations accounting for muscle fatigue are similar following isometric contractions with similar TTI. TTI should be considered in the exploration of muscle fatigue during sustained isometric contractions.

Authors+Show Affiliations

INSERM U1093, Université de Bourgogne, Dijon, France.INSERM U1093, Université de Bourgogne, Dijon, France.INSERM U1093, Université de Bourgogne, Dijon, France.INSERM U1093, Université de Bourgogne, Dijon, France.INSERM U1093, Université de Bourgogne, Dijon, France.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

25285471

Citation

Rozand, V, et al. "Neuromuscular Fatigue Following Isometric Contractions With Similar Torque Time Integral." International Journal of Sports Medicine, vol. 36, no. 1, 2015, pp. 35-40.
Rozand V, Cattagni T, Theurel J, et al. Neuromuscular fatigue following isometric contractions with similar torque time integral. Int J Sports Med. 2015;36(1):35-40.
Rozand, V., Cattagni, T., Theurel, J., Martin, A., & Lepers, R. (2015). Neuromuscular fatigue following isometric contractions with similar torque time integral. International Journal of Sports Medicine, 36(1), 35-40. https://doi.org/10.1055/s-0034-1375614
Rozand V, et al. Neuromuscular Fatigue Following Isometric Contractions With Similar Torque Time Integral. Int J Sports Med. 2015;36(1):35-40. PubMed PMID: 25285471.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Neuromuscular fatigue following isometric contractions with similar torque time integral. AU - Rozand,V, AU - Cattagni,T, AU - Theurel,J, AU - Martin,A, AU - Lepers,R, Y1 - 2014/10/06/ PY - 2014/10/7/entrez PY - 2014/10/7/pubmed PY - 2015/9/2/medline SP - 35 EP - 40 JF - International journal of sports medicine JO - Int J Sports Med VL - 36 IS - 1 N2 - Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25%, 50%, and 75% of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5±33.4 s, 35.1±16.8 s and 24.8±12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately after the sustained contractions. EMG activity of the vastus lateralis (VL) and -rectus femoris (RF) muscles was recorded during the sustained contractions. MVC torque reduction was similar in the 3 conditions after the exercise (-23.4±2.7%). VAL decreased significantly in a similar extent (-3.1±1.3%) after the 3 sustained contractions. Potentiated doublet amplitude was similarly reduced in the 3 conditions (-19.7±1.5%), but VL and RF M-wave amplitudes remained unchanged. EMG activity of VL and RF muscles increased in the same extent during the 3 contractions (VL: 54.5±40.4%; RF: 53.1±48.7%). These results suggest that central and peripheral alterations accounting for muscle fatigue are similar following isometric contractions with similar TTI. TTI should be considered in the exploration of muscle fatigue during sustained isometric contractions. SN - 1439-3964 UR - https://www.unboundmedicine.com/medline/citation/25285471/Neuromuscular_fatigue_following_isometric_contractions_with_similar_torque_time_integral_ L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-0034-1375614 DB - PRIME DP - Unbound Medicine ER -