John Temesi1, Thomas Rupp, Vincent Martin, Pierrick J Arnal, Léonard Féasson, Samuel Verges, Guillaume Y Millet. 1. 1Laboratoire de Physiologie de l'Exercice, Université de Lyon, Saint-Etienne, FRANCE; 2Laboratoire HP2, University Grenoble Alpes, Grenoble, FRANCE; 3INSERM, U1042, Grenoble, FRANCE; 4Laboratoire des Adaptations Métaboliques à l'Exercice en Conditions Physiologiques et Pathologiques, BP 10448, Clermont Université, Université Blaise Pascal, EA 3533, Clermont Ferrand, FRANCE; 5Unité de Myologie, Centre Référent Maladies Neuromusculaires Rares Rhône-Alpes, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Etienne, FRANCE; and 6Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, CANADA.
Abstract
PURPOSE: The well-established central deficit in ultraendurance running races is not understood. The use of transcranial magnetic stimulation (TMS) in parallel with peripheral nerve stimulation provides insight into the source of these central changes. The aims of this study were to determine the presence and magnitude of voluntary activation deficits, especially supraspinal deficits, after a mountain trail-running race and to determine whether this can be explained by simultaneous changes in corticospinal excitability and intracortical inhibition. METHODS: Neuromuscular function (TMS and femoral nerve electrical stimulation) of the knee extensors was evaluated before and after a 110-km ultratrail in 25 experienced ultraendurance trail runners during maximal and submaximal voluntary contractions and in relaxed muscle. RESULTS: Voluntary activation assessed by both femoral nerve electrical stimulation (-26%) and TMS (-16%) decreased and were correlated (P < 0.01). Decreases in potentiated twitch and doublet amplitudes were correlated with decreased voluntary activation assessed by TMS (P < 0.05). There was increased motor-evoked potential (MEP) amplitude (P < 0.05) without change in cortical silent period (CSP) elicited by TMS at optimal stimulus intensity. Conversely, CSP at suboptimal TMS intensity increased (P < 0.05) without concurrent change in MEP amplitude. CONCLUSIONS: The present results demonstrate the development of a large central activation deficit assessed by TMS, indicating that cortical motoneurons are severely impaired in their ability to fire at optimal frequency or be fully recruited after an ultraendurance running race. MEP and CSP responses suggest a shift in the sigmoidal MEP-stimulus intensity relationship toward larger MEP at higher TMS intensity without change in inflection point of the curve and a left shift in the CSP-stimulus intensity relationship.
PURPOSE: The well-established central deficit in ultraendurance running races is not understood. The use of transcranial magnetic stimulation (TMS) in parallel with peripheral nerve stimulation provides insight into the source of these central changes. The aims of this study were to determine the presence and magnitude of voluntary activation deficits, especially supraspinal deficits, after a mountain trail-running race and to determine whether this can be explained by simultaneous changes in corticospinal excitability and intracortical inhibition. METHODS: Neuromuscular function (TMS and femoral nerve electrical stimulation) of the knee extensors was evaluated before and after a 110-km ultratrail in 25 experienced ultraendurance trail runners during maximal and submaximal voluntary contractions and in relaxed muscle. RESULTS: Voluntary activation assessed by both femoral nerve electrical stimulation (-26%) and TMS (-16%) decreased and were correlated (P < 0.01). Decreases in potentiated twitch and doublet amplitudes were correlated with decreased voluntary activation assessed by TMS (P < 0.05). There was increased motor-evoked potential (MEP) amplitude (P < 0.05) without change in cortical silent period (CSP) elicited by TMS at optimal stimulus intensity. Conversely, CSP at suboptimal TMS intensity increased (P < 0.05) without concurrent change in MEP amplitude. CONCLUSIONS: The present results demonstrate the development of a large central activation deficit assessed by TMS, indicating that cortical motoneurons are severely impaired in their ability to fire at optimal frequency or be fully recruited after an ultraendurance running race. MEP and CSP responses suggest a shift in the sigmoidal MEP-stimulus intensity relationship toward larger MEP at higher TMS intensity without change in inflection point of the curve and a left shift in the CSP-stimulus intensity relationship.
Authors: J Mira; S J Aboodarda; M Floreani; R Jaswal; S J Moon; K Amery; T Rupp; Guillaume Y Millet Journal: Eur J Appl Physiol Date: 2018-08-18 Impact factor: 3.078
Authors: S J Aboodarda; J Mira; M Floreani; R Jaswal; S J Moon; K Amery; T Rupp; G Y Millet Journal: Eur J Appl Physiol Date: 2018-08-20 Impact factor: 3.078
Authors: Marc Jubeau; Thomas Rupp; Stephane Perrey; John Temesi; Bernard Wuyam; Patrick Levy; Samuel Verges; Guillaume Y Millet Journal: PLoS One Date: 2014-02-21 Impact factor: 3.240