title: Lower running performance and exacerbated fatigue in soccer played at 1600 m.
abstract: OBJECTIVE
  This study investigated the decrement in running performance of elite soccer players competing at low altitude and time course for abatement of these decrements.
  
  
  METHODS
  Twenty elite youth soccer players had their activity profile, in a sea-level (SL) and 2 altitude (Alt, 1600 m, d 4, and d 6) matches, measured with a global positioning system. Measures expressed in meters per minute of match time were total distance, low- and high-velocity running (LoVR, 0.01-4.16 m/s; HiVR, 4.17-10.0 m/s), and frequency of maximal accelerations (>2.78 m/s2). The peak and subsequent stanza for each measure were identified and a transient fatigue index calculated. Mean heart rate (HR) during the final minute of a submaximal running task (5 min, 11 km/h) was recorded at SL and for 10 d at Alt. Differences were determined between SL and Alt using percentage change and effect-size (ES) statistic with 90% confidence intervals.
  
  
  RESULTS
  Mean HR almost certainly increased on d 1 (5.4%, ES 1.01 ± 0.35) and remained probably elevated on both d 2 (ES 0.42 ± 0.31) and d3 (ES 0.30 ± 0.25), returning to baseline at d 5. Total distance was almost certainly lower than SL (ES -0.76 ± 0.37) at d 4 and remained probably reduced on d 6 (ES -0.42 ± 0.36). HiVR probably decreased at d 4 vs SL (-0.47 ± 0.59), with no clear effect of altitude at d 6 (-0.08 ± 0.41). Transient fatigue in matches was evident at SL and Alt, with a possibly greater decrement at Alt.
  
  
  CONCLUSIONS
  Despite some physiological adaptation, match running performance of youth soccer players is compromised for at least 6 d at low altitude.
authors.affiliation: Dept of Physiology, Australian Institute of Sport, Canberra, Australia.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Garvican
authors.forename: Kristal
authors.initials: K
authors.lastname: Hammond
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Varley
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gore
authors.forename: Francois
authors.initials: F
authors.lastname: Billaut
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Aughey
mesh_terms: D000054:Acceleration; D000064:Acclimatization; D000293:Adolescent; D000531:Altitude; D005080:Exercise Test; D040362:Geographic Information Systems; D006339:Heart Rate; D006801:Humans; D008297:Male; D009048:Motor Skills; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000502:physiology*; D012420:Running; D012916:Soccer; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult