title: Impairment of Sprint Mechanical Properties in an Actual Soccer Match: A Pilot Study.
abstract: OBJECTIVE
  To assess soccer-specific impairment of mechanical properties in accelerated sprinting and its relation with activity profiles during an actual match.
  
  
  METHODS
  Thirteen male field players completed 4 sprint measurements, wherein running speed was obtained using a laser distance-measurement system, before and after the 2 halves of 2 soccer matches. Macroscopic mechanical properties (theoretical maximal horizontal force [F0], maximal horizontal sprinting power [Pmax], and theoretical maximal sprinting velocity [V0]) during the 35-m sprint acceleration were calculated from speed-time data. Players' activity profiles during the matches were collected using global positioning system units.
  
  
  RESULTS
  After the match, although F0 and Pmax did not significantly change, V0 was reduced (P = .038), and the magnitude of this reduction correlated with distance (positive) and number (negative) of high-speed running, number of running (negative), and other low-intensity activity distance (negative) during the match. Moreover, Pmax decreased immediately before the second half (P = .014).
  
  
  CONCLUSIONS
  The results suggest that soccer-specific fatigue probably impairs players' maximal velocity capabilities more than their maximal horizontal force-production abilities at initial acceleration. Furthermore, long-distance running, especially at high speed, during the match may induce relatively large impairment of maximal velocity capabilities. In addition, the capability of producing maximal horizontal power during sprinting is presumably impaired during halftime of a soccer match with passive recovery. These findings could be useful for players and coaches aiming to train effectively to maintain sprinting performance throughout a soccer match when planning a training program.
authors.forename: Ryu
authors.initials: R
authors.lastname: Nagahara
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Morin
authors.forename: Masaaki
authors.initials: M
authors.lastname: Koido
mesh_terms: D000054:Acceleration; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D003163:Competitive Behavior / Q000502:physiology*; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D010101:Oxygen Consumption; D010865:Pilot Projects; D012420:Running / Q000502:physiology*; D012916:Soccer / Q000502:physiology*
keywords: GPS; acceleration; fatigue; laser; power