Video footage of matches played within the elite State - of - Origin series ( 2004 -- 11 ) and 2004 -- 11 NRL competition seasons was used in this study .
11 NRL competition seasons was freely available within the public domain .
Video footage of matches played within the elite State - of - Origin series ( 2004 -- 11 ) and 2004 -- 11 NRL competition seasons , which was freely available within the public domain , was used in this study .