Sizing up the shoulder charge ban raises challenge to the data
Read more: http://www.smh.com.au/rugby-league/league-news/sizing-up-the-shoulder-charge-ban-raises-challenge-to-the-data-20121123-29ypk.html#ixzz2D6Bft1EC
On report … Greg Inglis received a three week ban for his shoulder charge on Dean Young against the Dragons in July. Photo: Getty Images
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THE International Rugby Board's chief medical officer, Dr Martin Raftery, while endorsing the Australian Rugby League Commission's ban on the shoulder charge, disputes most of the data used to justify outlawing it.
Raftery, who recently returned from an international conference on concussion in Switzerland, is impeccably qualified to comment on injuries in both codes of rugby. He played for Cronulla (1974-80); was doctor for the Wallabies (2002-08) and the Dragons (1989-2004) and was appointed to the IRB's top medical post before last year's Rugby World Cup.
Rugby union has already banned the shoulder charge but not because players had grown 1.2 centimetres taller and 4 kilograms heavier since 2002, as the ARLC claimed, citing ''a detailed report''.
''This is an attempt to make a casual link with player size without any evidence of a link between size and injury,'' Raftery says. ''I am not aware of any data, including what is available from the 'detailed report' into shoulder charges, showing the increased size of athletes making a shoulder charge more likely to cause an injury, even if this would seem to be logical. Since 2000 [in rugby], despite a proven increase in weight, height and speed of players, injury rates have remained stable and actually returned to the pre-professional levels.''
Raftery also takes issue with NRL players who argue that the injury risk from a shoulder charge is minimal because these tackles represent a very small percentage of all tackles effected, a point ironically made by the ARLC which says shoulder charges comprise only 0.05 per cent of the 142,355 tackles made this year.
''I often hear people quoted saying that the injury risk from a shoulder charge is not that bad,'' he said. ''What these people fail to take into account is the injury per event. For example, in a game there may only be three shoulder charges with one injury (injury rate of one in three events) whereas there may be 10 injuries from tackles but there are 250 tackles in a game (injury rate from a tackle is one in every 25). In this scenario the shoulder charge is over eight times more likely to result in an injury. Data from rugby union confirms that a shoulder charge is 70 per cent more likely to result in an injury when compared with a tackle.''
The ARLC, in justifying the ban, cited a statistic that the average G-force of the shoulder charge measured from accelerometer data taken from GPS tracking was 76 per cent greater than a conventional head-on tackle (10.682 compared to 6.056).
This drew a cynical response from Raftery: ''Whilst this is impressive data, forces measured in American football with accelerometers in helmets do not show a linear relationship between head injury and force. There is also no evidence to suggest a head injury occurs at a specified force. Additionally, there is no link with the severity of a concussion and the level of force. What force data suggests is that athletes have different levels of susceptibility to head injury and the best approach is to eliminate direct forces to the head and face, rather than decide one level of force is OK and another is harmful.''
However, Raftery did endorse one statistic quoted by the ARLC - 17 per cent of shoulder charges resulted in contact with the head of the attacking player. ''The 2012 Concussion Conference in Zurich … strongly recommended that sports look to reduce attacks to the head and face in an effort to reduce concussion and any potential long-term sequelae,'' he said. ''If 17 per cent of shoulder charges result in contact with the head, then the risk is that one in every six shoulder charges will potentially cause a head injury.''
Apart from the ARLC being vulnerable to criticism it is grandstanding with flawed data, it risks accusations of hypocrisy, particularly regarding concerns over player safety. The ARLC had one representative at the Zurich conference, Dr Ron Muratore, the NRL's chief medical officer, whereas the AFL had six present, including an administrator.
