title: Influence of neuromuscular fatigue on accelerometer load in elite Australian football players.
abstract: OBJECTIVE
  To determine the impact of neuromuscular fatigue (NMF) assessed from variables obtained during a countermovement jump on exercise intensity measured with triaxial accelerometers (load per minute [LPM]) and the association between LPM and measures of running activity in elite Australian Football.
  
  
  METHODS
  Seventeen elite Australian Football players performed the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and provided a baseline measure of NMF (flight time:contraction time [FT:CT]) from a countermovement jump before the season. Weekly samples of FT:CT, coaches' rating of performance (votes), LPM, and percent contribution of the 3 vectors from the accelerometers in addition to high-speed-running meters per minute at >15 km/h and total distance relative to playing time (m/min) from matches were collected. Samples were divided into fatigued and nonfatigued groups based on reductions in FT:CT. Percent contributions of vectors to LPM were assessed to determine the likelihood of a meaningful difference between fatigued and nonfatigued groups. Pearson correlations were calculated to determine relationships between accelerometer vectors and running variables, votes, and Yo-Yo IR2 score.
  
  
  RESULTS
  Fatigue reduced the contribution of the vertical vector by (mean ± 90% CI) -5.8% ± 6.1% (86% likely) and the number of practically important correlations.
  
  
  CONCLUSIONS
  NMF affects the contribution of individual vectors to total LPM, with a likely tendency toward more running at low speed and less acceleration. Fatigue appears to limit the influence of the aerobic and anaerobic qualities assessed via the Yo-Yo IR2 test on LPM and seems implicated in pacing.
authors.affiliation: Australian Catholic University, Melbourne, Australia.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Cormack
authors.forename: Mitchell G
authors.initials: MG
authors.lastname: Mooney
authors.forename: Will
authors.initials: W
authors.lastname: Morgan
authors.forename: Michael R
authors.initials: MR
authors.lastname: McGuigan
mesh_terms: D061725:Accelerometry; D054874:Athletic Performance / Q000502:physiology*; D001315:Australia; D005538:Football / Q000502:physiology*; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology; D055815:Young Adult