title: Neuromuscular fatigue profile in endurance-trained and power-trained athletes.
abstract: OBJECTIVE
  This study examined the effects of training background on the relationship between the neuromuscular fatigue profile and maximal voluntary torque production in isometric, concentric, and eccentric contraction modes.
  
  
  METHODS
  Before and after three sets of 31 isokinetic concentric knee extensions at 60 degrees .s(-1), voluntary and electrically induced contractions were recorded in 14 endurance-trained (ENDU) men (seven cyclists: age 25 +/- 2 yr, mass 70 +/- 8 kg, height 175 +/- 5 cm; and seven triathletes: age 27 +/- 4 yr, mass 71 +/- 5 kg, height 179 +/- 6 cm) and seven explosive power-trained men (EXPLO: age 24 +/- 1 yr, mass 73 +/- 5 kg, height 179 +/- 4 cm). Maximal knee-extension torque, activation level (twitch interpolation technique), electromyographic activity of agonist and antagonist muscles, and twitch contractile properties were assessed.
  
  
  RESULTS
  At preexercise, the maximal voluntary isometric and concentric torques of EXPLO were greater than those of ENDU (P < 0.05). After the fatiguing exercise, significant isometric (18%; P < 0.01) and concentric (25%; P < 0.05) torque decreases in EXPLO were associated with, respectively, twitch torque (Pt) and maximal rate of twitch development (+dPt/dt) reductions (P < 0.01) and with an increase in the antagonist coactivation level (P < 0.01). No modification was observed for ENDU. Interestingly, the coactivation level was also increased (P < 0.01) in eccentric contraction for EXPLO, although the maximal eccentric torque decrease (P < 0.01) could not be specifically attributed to any group.
  
  
  CONCLUSIONS
  The fatiguing exercise induced central and peripheral adaptations, but the mechanisms differed regarding the contraction mode. At pre- and postfatiguing exercise, it seems that the neuromuscular profile depends on the subject's training background and the contraction modes used to assess fatigue.
authors.affiliation: Laboratory of Physiological Adaptations, Motor Performance and Health, Faculty of Sport Sciences, University of Nice Sophia-Antipolis, 261 route de Grenoble, 06205 Nice Cedex 3, France. garrande@unice.fr
authors.forename: Frédéric
authors.initials: F
authors.lastname: Garrandes
authors.forename: Serge S
authors.initials: SS
authors.lastname: Colson
authors.forename: Manuela
authors.initials: M
authors.lastname: Pensini
authors.forename: Olivier
authors.initials: O
authors.lastname: Seynnes
authors.forename: Patrick
authors.initials: P
authors.lastname: Legros
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005602:France; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D006113:United Kingdom