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Players getting away with illegal, dangerous ruck cleanouts
Author: Corporate Communication / Korporatiewe Kommunikasie [Alec Basson]
Published: 12/06/2019

​​​Every weekend Super Rugby fans and pundits alike vent their frustration as yet another illegal and dangerous cleanout of players at a ruck goes unpunished. And it seems that this will continue if statistics from last year are anything to go by.

“Our study on the sanctioning of illegal and dangerous cleanouts during the 2018 Super Rugby competition showed that referees didn't penalise as many of these as they should have," says Dr Wilbur Kraak from the Department of Sport Science at Stellenbosch University. He conducted the research with colleagues from the same department as well as the Department of Health at the University of Bath in England. The findings of their study were published recently in the open-access journal Frontiers in Psychology.

Using the video editing tool Nacsport Basic plus, Kraak and his fellow researchers coded and analysed video recordings of 120 round robin matches during the competition to determine the rate at which illegal and dangerous ruck cleanouts were penalised by referees. They also enlisted the help of an international referee and rugby injury specialist. The Western Province Rugby Union video analysis department supplied the video recordings.

Kraak says that to their knowledge, this was the first time that the non-sanctioning of dangerous illegal cleanouts at the ruck by on-field referees during a game has been investigated. The ruck is a phase of play where one or more players from each team remain on their feet and are in physical contact close around the ball on the ground.

Illegal ruck cleanouts

The researchers found that there were 22 281 ruck clean outs during the 2018 Super Rugby competition at an average of 186 cleanouts per game.

“Our study revealed that 2 111 (9%) of these cleanouts were deemed illegal according to the 2018 World Rugby (WR) Laws of the Game at an average of 18 per match. Referees did not penalise 1 953 (93%) of the illegal ruck cleanouts at an average of 16 per game."

Kraak adds that of the total illegal ruck cleanouts not sanctioned by referees, 1 087 (57%) were considered dangerous at an average of 10 per match.

He points out that the majority of illegal ruck clean outs not penalised by referees were for “not supporting own body weight" (624 or 32%), followed by “side entry" (318 or 16%), “shoulder charge" (317 or 16%) and “contact above the shoulder" (247 or 13%).

“The attacking team were not penalised when 'not supporting own body weight' (599 or 96%) and 'side entry' (303 or 95%) compared to the defending team for 'cleaning a player not involved in ruck' (12 or 27%) and 'joining the ruck from an offside position' (22 or 12%).

“The illegal ruck clean outs not penalised for the defending team were 'cleaning a player not involved in ruck' (12 or 27%), followed by 'joining the ruck from an offside position' (9 or 12%).

Referees did not penalise the attacking team for 95% (1037 of 1087) of the dangerous illegal ruck clean outs and the majority of the dangerous illegal cleanouts not penalised were 'shoulder charge,' 'neck roll,' and 'contact above the shoulder'."

Kraak says their findings should be a concern for rugby referee stakeholders from an error rate perspective.

“A greater concern for rugby safety and rugby referee stakeholders should be that 1087 of the non-sanctioned ruck cleanouts were deemed dangerous, which could pose an injury risk to the players involved in the ruck area.

“Given that more or less 10% of all injuries during a game are associated with the ruck, this is something that needs to be addressed."

Kraak says referees can minimize the risk of players getting injured by focusing on “shoulder charge," “neck roll," and “contact above the shoulder," given the high proportion of these infringements that are deemed dangerous.

“Surveillance of legal and illegal (dangerous and not dangerous) ruck cleanouts and the sanctions imposed by referees will help identify whether the referees are actually enforcing the laws according to the WR law book."

Ruck drills

Kraak and his fellow researchers also have some advice for coaches. ​“Because the ruck is a dynamic situation, coaches should not coach the ruck clean out in isolation because this limits the decision-making ability of the players. 

“Ruck drills should include the initial tackle, fight for dominance by the ball carrier, placement of the ball, and clearing techniques in the same drill because this will assist players with adjustment and decision-making based on the situation."

The researchers encourage coaches to invite referees to attend and officiate contact training sessions and drills according to rugby's current laws as this will provide clarity to both players and coaches with input from the referees.

​Kraak says referees, players, coaches and other rugby stakeholders will benefit from their study. “The findings of our study can lead to the development and implementation of further injury prevention strategies to make the game safer for all the role-players involved."

  • SOURCE: Kraak, WJ et al 2019. Sanctioning of Illegal and Dangerous Ruck Cleanouts During the 2018 Super Rugby Competition. Frontiers in Psychology, Vol 10.


Dr Wilbur Kraak

Department of Sport Science

Faculty of Medicine and Health Sciences

Stellenbosch University

Cell: 0835910321

Tel: 021 808 2379

E-mail: /

       ISSUED BY

​Martin Viljoen

Manager: Media

Corporate Communication

Stellenbosch University

Tel: 021 808 4921