Rugby demands, recovery and injury prevention

Rugby is a contact sport that involves multiple periods of high intensity running, interspersed with period of slow jogging, walking and standing, as well as physical contact in the form of tackles, rucks, mauls, lineouts and scrums.  The demands of the sport put a premium on recovery post-participation, both as a performance aid and a potential means of injury prevention.

The injury incidence in elite rugby has been documented as between 75 and 90 injuries per 1000 hours, which equates to three to four injuries per match.  At lower ages and sub-elite, injury incidence is slightly lower (60 – 70 injuries per 1000 hours in the U20 RWC and U20 World Trophy, for example). 

There is no direct data or studies that link injury risk to recovery (or failure to recover) after playing in a rugby match.  Nor is such data likely, because of the constraints of doing such research with adequate numbers.  However, it is reasonable to consider that given the physical demands of the match, combined with the high injury incidence, that giving players adequate recovery time between matches is an essential part of managing injury risk in the sport. 

Conversely, failure to recover from rugby matches prior to the start of the subsequent one would be expected to increase the risk to a player, and to compromise performance.  It is known, for instance, that fatigue is a risk factor for injury, and so players with residual fatigue at the start of their next match may have greater injury risk.  Also, it must be considered that after a match, many players may have physical ailments such as bruising and muscle damage that do not necessarily meet the definition of an injury (which would require them to miss training for at least one day), but that do need time to recover, repair and regenerate, and should that player be required to play another match too soon, that recovery would be denied and any worsening of that affliction would lead to a more serious injury.

Finally, preparation for the next match is also required, which creates a practical constraint for coaches and players, if insufficient days are provided between games.  A rest day, or a day of low volume and low intensity training would be required immediately after a match, with another low volume/intensity training day the day before.  If insufficient days recovery are scheduled, actual conditioning and preparation will be compromised over the course of a tournament.

The challenge for the sport, in the absence of direct research, is to estimate the time required for recovery so that tournament and competition organizers can schedule games in reasonable time frames without compromising player welfare and performance.

 

Data on performance impairments and recovery profiles from rugby

The best available data on recovery after rugby comes from Sevens rugby and Rugby League, with few studies in Fifteens.  What this data has revealed is that markers or indicators of muscle damage and neuromuscular fatigue are present for at least three days after play.  In one example, Rugby League players performed a countermovement jump before and after a match for a period of days.  A countermovement jump measures lower body power and neuromuscular capacity, and thus provides a good indicator of recovery for explosive efforts.  It was found that the performance of players was impaired for at least four days after the game.  This suggests that full recovery of the neuromuscular system had not been achieved at Day 4 post-play.

Other studies have found slightly faster recovery.  For example, West et al showed that lower leg body output was impaired after play, this time in Rugby Union players, and only returned to pre-match levels after 60 hours (third day) post-play. 

Another measurement that has been used to assess match-induced damage and recovery is creatine kinase.  This is an enzyme that is present inside muscle, and so when measured when in the blood, means that muscle damage has occurred.  Tracking the changes to creatine kinase therefore provides an indication of the state of muscle damage.  Studies that have done this after playing Rugby League have found that creatine kinase levels increase dramatically in the first few hours after play, reach peak levels 24 to 48 hours after the match, and then decline over the next 36 to 72 hours.  Normal return to baseline takes about 60 hours, though in some cases has taken 120 hours (5 days).

The degree to which creatine kinase levels change has been related to the number and frequency of contact events experienced by a player during the match.  Creatine kinase levels are also related to changes in neuromuscular function and power output, described previously.  This line of research, while in Rugby League, again suggests that earliest recovery is three days after play, with evidence showing that many players require four days for muscle function to return to normal, and five days for muscle damage to be fully resolved.

In Rugby Union, most of the studies on recovery have been conducted in Sevens players, who regularly have to play multiple matches over two or three days, followed by a short recovery, and then a second tournament as part of the World Series.  West et al found that after a full weekend of Sevens play (one competition), lower body power output and countermovement jump height were suppressed and remained so for at least 60 hours, with full recovery achieved by the following tournament (five days later) by some players only, with an average reduction of power of 8% even five days later.  It was suggested that “more intensive approaches to recovery should be considered”, given the constraints imposed by the calendar.

The problem may also be viewed with a different perspective.  In a research study on the World Rugby Under 20 Trophy, it was found that players from one team had only minimal impairment in neuromuscular function and increases in creatine kinase by the fourth match of five at the tournament, and that the high-speed running of the players during matches was maintained at the same level throughout.  Importantly, in this tournament, there were four clear days for recovery between each match, which does suggest that full or near-full recovery can be achieved in this period.  While this is a study on one team only, it supports the previous studies that find a return to baseline happens at approximately day 5.

 

World Rugby recommendation

World Rugby recognizes that the above research has many limitations.  Most of the studies are on Rugby League players, and those often involve junior and sub-elite players who may not have the same level of conditioning as adult and international Rugby Union players.  However, their level may also mean that their matches are not of the same intensity and thus creating the same risk as would be the case for higher level adults.  Other studies in Seven may have only partial relevance to the Fifteens question.

However, all considered, there is no major basis to assume that the recovery profile of Fifteens players would differ.  In fact, given that muscle damage has been related to physical contacts, it may be that Fifteens players experience even greater decrements than those of Rugby league and Sevens players.

Therefore, given:

1. The finding that power output and neuromuscular function are impaired for at least 60 hours, and for up to five days in some studies;
2. The presence of muscle damage markers for four to five days after match-play;
3. The finding that high-speed running, neuromuscular function and muscle damage are maintained and normalized over a tournament where matches are played with at least four days of recovery

World Rugby would recommend that at least four clear recovery days are provided after a match to ensure adequate recovery and preparation for the next match.  That is, three clear days is insufficient time to recover, and so a second match should not be played on the fourth day after a previous match.

For example, if Match 1 is played on a Saturday, full recovery should be allowed on Sunday, Monday, Tuesday, and Wednesday (four clear days), with Match 2 being played on Thursday at the earliest.

The available evidence does suggest that any reduction in the recovery may force players into high intensity, high contact situations while their neuromuscular performance and muscle damage remain significantly impaired compared to baseline. 

Even at four clear rest days, there is a chance that players are not fully recovered, but with evidence-based recovery strategies, training management between matches, and player rotation policies, teams should be able to optimize performance and reduce injury risk.  In this regard, tournament organizers who schedule matches with this minimum four clear days of recovery must also consider how best to optimize recovery in players, and this may include providing recovery centres and recovery modalities such as massage, icing and high quality nutrition options for teams.

It is accepted that this recommendation will have operational and financial implications for tournament planning as well as potential implications on the contracting of sub elite players participating in these tournaments, and may not be achievable in the immediacy for tournaments already scheduled. A period of consultation and adoption of these guidelines is anticipated, at global, regional and domestic level with an initial focus on World Rugby’s portfolio of tournaments and those tournaments delivered by the Regional Associations of World Rugby.

 

References

Carling, C.J., et al., Exposure time, running and skill-related performance in international u20 rugby union players during an intensified tournament. PloS one, 2017. 12(11): p. e0186874.

Johnston, R.D., et al., Influence of physical contact on neuromuscular fatigue and markers of muscle damage following small-sided games. Journal of Science and Medicine in Sport, 2014. 17(5): p. 535-540.

Lacome, M., et al., Workload, Fatigue and Muscle Damage in an u20 Rugby Union Team Over an Intensified International Tournament. International journal of sports physiology and performance, 2018: p. 1-23.

McLean, B.D., et al., Neuromuscular, endocrine, and perceptual fatigue responses during different length between-match microcycles in professional rugby league players. International journal of sports physiology and performance, 2010. 5(3): p. 367-383.

McLellan, C.P., D.I. Lovell, and G.C. Gass, Markers of postmatch fatigue in professional rugby league players. The Journal of Strength & Conditioning Research, 2011. 25(4): p. 1030-1039.

McLellan, C.P., D.I. Lovell, and G.C. Gass, Creatine kinase and endocrine responses of elite players pre, during, and post rugby league match play. The Journal of Strength & Conditioning Research, 2010. 24(11): p. 2908-2919.

McLellan, C.P., D.I. Lovell, and G.C. Gass, Biochemical and endocrine responses to impact and collision during elite rugby league match play. The Journal of Strength & Conditioning Research, 2011. 25(6): p. 1553-1562.

Twist, C., et al., Neuromuscular, biochemical and perceptual post-match fatigue in professional rugby league forwards and backs. Journal of Sports Sciences, 2012. 30(4): p. 359-367.

West, D.J., et al., Profiling the time-course changes in neuromuscular function and muscle damage over two consecutive tournament stages in elite rugby sevens players. Journal of science and medicine in sport, 2014. 17(6): p. 688-692.

West, D.J., et al., Neuromuscular function, hormonal, and mood responses to a professional rugby union match. The Journal of Strength & Conditioning Research, 2014. 28(1): p. 194-200.