In-Game Fatigue and Replacements in Rugby Union: Research Insights

DEPARTMENT FOR HEALTH The contribution of in-game fatigue and use of replacements to injury risk in professional rugby union Simon Roberts Dr Simon Roberts: s.p.roberts@bath.ac.uk CONTACT

Replacements: what do people think? Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk CONTACT CONTACT 2

What do we know from the literature? Injury incidence is lower in the first 20 min of a match Williams et al. 2013 Player time-in-game does not affect tackler or ball carrier technique Tierney et al. 2018 Replacements have a short-term impact in terms of player running performance Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk Lacome et al. 2016 Injury incidence is greater in starters (114 /1000 hours) vs. replacements (87 /1000 hours) Changing from unlimited to 12 interchanges in sub-elite Rugby League reduced injury incidence by 30% Brooks et al. 2004 CONTACT CONTACT Gabbett et al. 2005 3

Project research questions Study 1 Do more injuries occur late in matches and are starters or replacements more likely to get injured? I. Injury incidence, severity and patterns by match quarter and in starters vs. replacements Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk II. Time to injury from start of game (in starters) and entry onto field (in replacements) III. Is there an association between the number of replacements made in a game and the incidence or severity of injuries? CONTACT CONTACT 4

Study 1 - Methods (2011 2019) Player match exposures: >2000 Team games Shirt number: Starter or Replacement Exposure minutes per player Playing position Australia New Zealand South Africa (2016 2018) Player injuries Greater than 24 hours time-loss Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk Severity (days absence) Diagnosis Injury Event Welsh regions Match quarter Playing position CONTACT CONTACT 5

Study 1 Initial findings: English Premiership Outside backs Inside backs Back row Second row Scrum half Front row Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk CONTACT CONTACT 6

Study 1 Initial findings: English Premiership Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk CONTACT CONTACT 7

Study 2 Do tackles between starters and replacements have a greater propensity for injury than those of the same status (i.e., both starters or both replacements)? ~900 tackle injuries~3600 control tackles Four seasons (2015/16 2018/19) Tackles coded by video analysis Tackler Ball carrier Injury risk per 1000 tackles: Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk Starter vs Starter Severity Starter/Replacement Starter vs Replacement Timing Exact minutes on pitch Replacement vs Replacement Injured/non injured Team CONTACT CONTACT 8

Summary What we can show from this observational study Current status of injury risk to starters and replacements during match play under current laws. What we should be cautious with at this stage Whether player behaviour would change if the number of replacements were reduced and what impact this may have on injuries. Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk CONTACT CONTACT 9

Thank you for your attention Dr Simon Roberts: s.p.roberts@bath.ac.uk Dr Simon Roberts: s.p.roberts@bath.ac.uk CONTACT CONTACT 10