title: Analysis of Physical Collisions in Elite National Rugby League Match Play.
abstract: OBJECTIVE
  To investigate the impact forces of collision events during both attack and defense in elite rugby league match play and to compare the collision profiles between playing positions.
  
  
  METHODS
  26 elite rugby league players.
  
  
  METHODS
  Player collisions were recorded using an integrated accelerometer in global positioning system units (SPI-Pro X, GPSports). Impact forces of collisions in attack (hit-ups) and defense (tackles) were analyzed from 359 files from outside backs (n = 78), adjustables (n = 97), wide-running forwards (n = 136), and hit-up forwards (n = 48) over 1 National Rugby League season.
  
  
  RESULTS
  Hit-up forwards were involved in 0.8 collisions/min, significantly more than all other positional groups (wide-running forwards P = .050, adjustables P = .042, and outside backs P = .000). Outside backs experienced 25% fewer collisions per minute than hit-up forwards. Hit-up forwards experienced a collision within the 2 highest classifications of force (≥ 10 g) every 2.5 min of match play compared with 1 every 5 and 9 min for adjustables and outside backs, respectively. Hit-up forwards performed 0.5 tackles per minute of match play, 5 times that of outside backs (ES = 1.90; 95% CI [0.26,3.16]), and 0.2 hit-ups per minute of match play, twice as many as adjustables.
  
  
  CONCLUSIONS
  During a rugby league match, players are exposed to a significant number of collision events. Positional differences exist, with hit-up and wide-running forwards experiencing greater collision events than adjustables and outside backs. Although these results may be unique to the individual team's defensive- and attacking-play strategies, they are indicative of the significant collision profiles in professional rugby league.
authors.affiliation: Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia.
authors.forename: Cloe
authors.initials: C
authors.lastname: Cummins
authors.forename: Rhonda
authors.initials: R
authors.lastname: Orr
mesh_terms: D000054:Acceleration; D056044:Actigraphy / Q000295:instrumentation; D000328:Adult; D056352:Athletes / Q000523:psychology; D054874:Athletic Performance / Q000523:psychology; D001696:Biomechanical Phenomena; D003163:Competitive Behavior; D005538:Football / Q000523:psychology; D040362:Geographic Information Systems / Q000295:instrumentation; D006801:Humans; D008297:Male; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000502:physiology*; D012420:Running; D013647:Task Performance and Analysis; D013997:Time Factors; D014741:Video Recording; D055815:Young Adult