title: Mechanical Properties of Sprinting in Elite Rugby Union and Rugby League.
abstract: OBJECTIVE
  To compare mechanical properties of overground sprint running in elite rugby union and rugby league athletes.
  
  
  METHODS
  Thirty elite rugby code (15 rugby union and 15 rugby league) athletes participated in this cross-sectional analysis. Radar was used to measure maximal overground sprint performance over 20 or 30 m (forwards and backs, respectively). In addition to time at 2, 5, 10, 20, and 30 m, velocity-time signals were analyzed to derive external horizontal force-velocity relationships with a recently validated method. From this relationship, the maximal theoretical velocity, external relative and absolute horizontal force, horizontal power, and optimal horizontal force for peak power production were determined.
  
  
  RESULTS
  While differences in maximal velocity were unclear between codes, rugby union backs produced moderately faster split times, with the most substantial differences occurring at 2 and 5 m (ES 0.95 and 0.86, respectively). In addition, rugby union backs produced moderately larger relative horizontal force, optimal force, and peak power capabilities than rugby league backs (ES 0.73-0.77). Rugby union forwards had a higher absolute force (ES 0.77) despite having ~12% more body weight than rugby league forwards.
  
  
  CONCLUSIONS
  In this elite sample, rugby union athletes typically displayed greater short-distance sprint performance, which may be linked to an ability to generate high levels of horizontal force and power. The acceleration characteristics presented in this study could be a result of the individual movement and positional demands of each code.
authors.affiliation: Sports Performance Research Inst New Zealand (SPRINZ), Auckland University of Technology, Auckland, NZ.
authors.forename: Matt R
authors.initials: MR
authors.lastname: Cross
authors.forename: Matt
authors.initials: M
authors.lastname: Brughelli
authors.forename: Scott R
authors.initials: SR
authors.lastname: Brown
authors.forename: Pierre
authors.initials: P
authors.lastname: Samozino
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Gill
authors.forename: John B
authors.initials: JB
authors.lastname: Cronin
authors.forename: Jean-Benoît
authors.initials: JB
authors.lastname: Morin
mesh_terms: D000054:Acceleration; D000328:Adult; D056352:Athletes; D054874:Athletic Performance; D001696:Biomechanical Phenomena; D001835:Body Weight; D003430:Cross-Sectional Studies; D005538:Football; D006801:Humans; D008297:Male; D009043:Motor Activity; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D012420:Running; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult