Rugby World Cup: why size matters

The Rugby World Cup saw heavier teams take to the pitch than ever beforeEngland's players are on average over 10% heavier than in 1991. So what impact is the increasing size of players having on rugby? Find out more here

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Isaac Newton’s second law of motion says force is equal to mass times acceleration. Which means if athletes want to put in the hard hits it helps to be fast, big and strong.

Collision sports have always been rough and tough but as they’ve become more professional players have become bigger and stronger which means their blows have become, well… But what impact is this having on collision sports?

When it comes to professional sports, winning is everything and in collision sports like American football and rugby marginal gains can come from having bigger and stronger athletes.

Twenty-eight years ago the average weight of the 1991 World Cup England squad was 94.8kg. In 2019 it’s 105.9kg - That’s more than a 10% increase.

How have rugby players got so big? In 1995 rugby union went from an amateur sport to professional. Media moguls, like Rupert Murdoch, threw money at broadcast rights and the sport was to change for ever. Players had to go from the everyman to superman adopting strict fitness regimes, training schedules and diet plans all to maximise their potential. Bigger players can get tired more easily but a rule change, allowing more substitutions, meant players no longer needed to last a full game. The result has been a super breed of player. Just take a look at Jeremy Guscott in 1995 compared with his equivalent, Manu Tuilagi, in 2019.

But since professionalism there have also been changes in rugby injuries and experts think this may be caused by players with a higher body mass. Between 1996 and 2000 immediately after the game went professional the rate of injuries among elite Australian players increased by 57%. At Bath University researchers have been recording rugby-injury data since 2002. They found the rate of injuries hasn’t actually increased since then but the nature of the injuries has.

The research team have also found that the rate of concussions among players has increased since 2011 and now there is an average of around one incident of concussion per match. The detection of concussion has improved dramatically and this might be one of the reasons why there’s been an increase in concussion. Of course the other thing is that the game has changed and things like an increase in the speed of the game, the amount of time when the ball is in play, and therefore the number of tackles and the size of those collisions may also play a role.

It’s not just rugby. American football has been rocked by reports that an increasing number of retired NFL players who have suffered concussions have developed memory and cognitive issues. A study of deceased NFL players found that 99% of them had a degenerative brain disease believed to be caused by repeated blows to the head. The NFL has faced a series of lawsuits from former players who suffered head trauma and were demanding compensation. They reached an extremely expensive settlement and to a certain extent, they’ve learned a lesson from that or been forced to.

In an effort to reduce concussions, the NFL banned helmet-to-helmet hits punishing them with a penalty and sometimes even by suspending the player. Across other collision sports, there have been changes around concussion detection and prevention. These include substitutions for head injuries while a player is assessed by a doctor off the pitch.

And in the 2019 Rugby World Cup new rules around high tackles were brought in which officials say have led to a 35% reduction in the rate of concussion.

The impact of the new breed of bigger players goes much further than what happens on the pitch. Behind the scenes, it’s affecting the laws of the game and the players’ safety. As the supermen of collision sports become ever more powerful balancing their welfare will become the biggest challenge.

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