title: Mental Fatigue Impairs Intermittent Running Performance.
abstract: OBJECTIVE
  The purpose of the study was to investigate the effects of mental fatigue on intermittent running performance.
  
  
  METHODS
  Ten male intermittent team sports players performed two identical self-paced, intermittent running protocols. The two trials were separated by 7 d and preceded, in a randomized-counterbalanced order, by 90 min of either emotionally neutral documentaries (control) or the AX-continuous performance test (AX-CPT; mental fatigue). Subjective ratings of fatigue and vigor were measured before and after these treatments, and motivation was recorded before the intermittent running protocol. Velocity, heart rate, oxygen consumption, blood glucose and lactate concentrations, and ratings of perceived exertion (RPE) were measured throughout the 45-min intermittent running protocol. Session RPE was recorded 30 min after the intermittent running protocol.
  
  
  RESULTS
  Subjective ratings of fatigue were higher after the AX-CPT (P = 0.005). This mental fatigue significantly reduced velocity at low intensities (1.28 ± 0.18 m·s vs 1.31 ± 0.17 m·s; P = 0.037), whereas high-intensity running and peak velocities were not significantly affected. Running velocity at all intensities significantly declined over time in both conditions (P < 0.001). Oxygen consumption was significantly lower in the mental fatigue condition (P = 0.007). Other physiological variables, vigor and motivation, were not significantly affected. Ratings of perceived exertion during the intermittent running protocol were not significantly different between conditions despite lower overall velocity in the mental fatigue condition. Session RPE was significantly higher in the mental fatigue condition (P = 0.013).
  
  
  CONCLUSIONS
  Mental fatigue impairs intermittent running performance. This negative effect of mental fatigue seems to be mediated by higher perception of effort.
authors.affiliation: 1Sport and Exercise Discipline Group, Faculty of Health, University of Technology Sydney, AUSTRALIA; and 2Endurance Research Group, School of Sport and Exercise Sciences, University of Kent at Medway, UNITED KINGDOM.
authors.forename: Mitchell R
authors.initials: MR
authors.lastname: Smith
authors.forename: Samuele M
authors.initials: SM
authors.lastname: Marcora
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Coutts
mesh_terms: D054874:Athletic Performance / Q000523:psychology*; D018592:Cross-Over Studies; D006801:Humans; D008297:Male; D005222:Mental Fatigue; D012420:Running / Q000523:psychology*; D013177:Sports; D055815:Young Adult