Rugby Union - Premiership - Wasps v Northampton Saints - Ricoh Arena, Coventry, Britain - April 29, 2018 Northampton Saints' Jamie Gibson during a ruck Action Images/Andrew Boyers 

Rugby Union - Six Nations Championship - Ireland vs Wales - Aviva Stadium, Dublin, Republic of Ireland - February 24, 2018 Ireland’s Conor Murray gestures as his team mates build a ruck REUTERS/Clodagh Kilcoyne 

Rugby Union - Six Nations Championship - Ireland vs Wales - Aviva Stadium, Dublin, Republic of Ireland - February 24, 2018 Ireland’s Conor Murray prepares to pass the ball after a ruck REUTERS/Clodagh Kilcoyne 

FILE PHOTO: Britain Rugby Union - England v Italy - Six Nations Championship - Twickenham Stadium, London - 26/2/17 England's Ben Youngs in action with Italy's Ornel Gega Reuters / Toby Melville / File Photo / Livepic EDITORIAL USE ONLY. 

2016 Rio Olympics - Rugby - Women's Placing 11-12 Colombia v Kenya - Deodoro Stadium - Rio de Janeiro, Brazil - 08/08/2016. Doreen Remour (KEN) of Kenya pushes Celestine Masinde (KEN) of Kenya from a ruck. REUTERS/Alessandro Bianchi (BRAZIL - Tags: SPORT OLYMPICS SPORT RUGBY) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS.
Picture Supplied by Action Images 

2016 Rio Olympics - Rugby - Women's Semifinals Australia v Canada - Deodoro Stadium - Rio de Janeiro, Brazil - 08/08/2016. Alicia Quirk (AUS) of Australia holds the ball in a ruck. REUTERS/Alessandro Bianchi (BRAZIL - Tags: SPORT OLYMPICS SPORT RUGBY) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS.
Picture Supplied by Action Images 

New Zealand All Blacks' Brad Thorn (L) is held in a ruck by France's Alexis Palisson (top) and captain Thierry Dusautoir (bottom) during their Rugby World Cup final match at Eden Park in Auckland October 23, 2011. REUTERS/Nigel Marple (NEW ZEALAND - Tags: SPORT RUGBY)

New Zealand All Blacks' Piri Weepu moves the ball out from a ruck during their Rugby World Cup final match against France at Eden Park in Auckland October 23, 2011. REUTERS/David Gray (NEW ZEALAND - Tags: SPORT RUGBY IMAGE OF THE DAY TOP PICTURE)

France's Dimitri Yachvili (C) clears the ball from a ruck during their Rugby World Cup final match against New Zealand All Blacks at Eden Park in Auckland October 23, 2011. REUTERS/Anthony Phelps (NEW ZEALAND - Tags: SPORT RUGBY)

New Zealand All Blacks' Sam Whitelock pushes the ball out from a ruck during their Rugby World Cup semi-final match against Australia Wallabies at Eden Park in Auckland October 16, 2011. REUTERS/Anthony Phelps (NEW ZEALAND - Tags: SPORT RUGBY)

Australia Wallabies' Ben Alexander (top) works at the top of a ruck during their Rugby World Cup semi-final match against New Zealand All Blacks at Eden Park in Auckland October 16, 2011. REUTERS/David Gray (NEW ZEALAND - Tags: SPORT RUGBY)

France's Morgan Parra gets caught at the bottom of a ruck during their Rugby World Cup semi-final match against Wales at Eden Park in Auckland October 15, 2011. REUTERS/David Gray (NEW ZEALAND - Tags: SPORT RUGBY IMAGE OF THE DAY TOP PICTURE)

Ireland's Stephen Ferris pushes the ball out from a ruck during their Rugby World Cup quarter-final match against Wales at Wellington Regional Stadium October 8, 2011. REUTERS/David Gray (NEW ZEALAND - Tags: SPORT RUGBY)

Italy captain Sergio Parisse pushes the ball out from a ruck during their Rugby World Cup Pool C match against Ireland at Otago Stadium in Dunedin October 2, 2011. REUTERS/Brandon Malone (NEW ZEALAND - Tags: SPORT RUGBY)

Fiji's Leone Nakarawa (L) tips Wales' George North (C) upside down in a ruck during their Rugby World Cup Pool D match at Waikato Stadium in Hamilton October 2, 2011. REUTERS/Nigel Marple (NEW ZEALAND - Tags: SPORT RUGBY IMAGE OF THE DAY TOP PICTURE)

Romania and England players contest a ruck during their Rugby World Cup Pool B match at Otago Stadium in Dunedin September 24, 2011. REUTERS/Marcos Brindicci (NEW ZEALAND - Tags: SPORT RUGBY)

Australia Wallabies captain Will Genia passes the ball out from a ruck during their Rugby World Cup Pool C match against the U.S. at Wellington Regional Stadium in Wellington September 23, 2011. REUTERS/Anthony Phelps (NEW ZEALAND - Tags: SPORT RUGBY)

Colin Hawley of the U.S. moves the ball out from a ruck during their Rugby World Cup Pool C match against Australia Wallabies at Wellington Regional Stadium in Wellington September 23, 2011. REUTERS/David Gray (NEW ZEALAND - Tags: SPORT RUGBY)

South Africa Springboks' Pierre Spies passes the ball out of a ruck during their Rugby World Cup Pool D match against Namibia at North Harbour Stadium in Auckland September 22, 2011. REUTERS/Bogdan Cristel (NEW ZEALAND - Tags: SPORT RUGBY)

Georgia's Mamuka Gorgodze (7) pushes the ball back from a ruck during their Rugby World Cup Pool B match against England at Otago Stadium in Dunedin September 18, 2011. REUTERS/Brandon Malone (NEW ZEALAND - Tags: SPORT RUGBY)

Georgia's Mamuka Gorgodze pushes the ball out from a ruck during their Rugby World Cup Pool B match against England at Otago Stadium in Dunedin September 18, 2011. REUTERS/Stefan Wermuth (NEW ZEALAND - Tags: SPORT RUGBY)

South Africa Springboks' Odwa Ndungane looks out from a ruck during their Rugby World Cup Pool D match against Fiji at Wellington Regional Stadium in Wellington September 17, 2011. REUTERS/David Gray (NEW ZEALAND - Tags: SPORT RUGBY)

Romania's Daniel Carpo (C) moves the ball out of the ruck during their Rugby World Cup Pool B match against Scotland at Rugby Park Stadium in Invercargill September 10, 2011. REUTERS/Brandon Malone (NEW ZEALAND - Tags: SPORT RUGBY)

Duane Vermeulen of South Africa's Stormers bleeds as he joins a ruck during their Super 15 rugby union match against Australia's Rebels in Melbourne June 3, 2011. REUTERS/Brandon Malone (AUSTRALIA - Tags: SPORT RUGBY) 

Barbarians' Carl Hayman (back, R) pulls England's Joe Marler (front, R) out of a ruck during their rugby union match at Twickenham, London May 29, 2011. REUTERS/Russell Cheyne (BRITAIN - Tags: SPORT RUGBY) 

Andries Bekker (top) of South Africa's Stormers signals from the middle of a ruck during their Super 15 rugby union match against Australia's Brumbies in Canberra May 28, 2011. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT RUGBY) 

England's Mike Tindall protects his head in a ruck against France during their Six Nations rugby union championship match at Twickenham in west London February 26, 2011. REUTERS/Russell Cheyne (BRITAIN - Tags: SPORT RUGBY) 

Australia's Richard Brown moves the ball out of the ruck during their rugby union test match against Australia in Sydney June 19, 2010. REUTERS/Tim Wimborne (AUSTRALIA - Tags: SPORT RUGBY) 

Stormers Pieter Louw protects the ball in a ruck during their Super 14 Rugby union final clash against the Bulls in Soweto, Johannesburg, May 29, 2010. REUTERS/Siphiwe Sibeko (SOUTH AFRICA - Tags: SPORT RUGBY) 

Andy Ellis (C, front) of New Zealand's Crusaders kicks the ball over the ruck during their Super 14 match against Australia's Brumbies in Christchurch May 14, 2010. REUTERS/Simon Baker (NEW ZEALAND - Tags: SPORT RUGBY) 

Tiaan Liebenberg of South Africa's Stormers gets a pass away from the base of the ruck against New Zealand's Auckland Blues during their Super 14 rugby match at Eden Park in Auckland April 10, 2010. The Stormers won the match 33-21. REUTERS/Nigel Marple (NEW ZEALAND - Tags: SPORT RUGBY) 

Sham Wai Sum (C) of Hong Kong lies on the bottom of a ruck during the women's rugby sevens bronze medal match against Guam at the East Asian Games in Hong Kong December 6, 2009. REUTERS/Bobby Yip (CHINA SPORT RUGBY) 

England's Steve Borthwick (R) wrestles France's Julien Bonnaire for the ball during their Six Nations rugby match at Twickenham in London March 15, 2009. REUTERS/Eddie Keogh (BRITAIN SPORT RUGBY) 

England's centre Mike Tindall displays ruck marks through his ripped shirt against France during their six Nations rugby match at Twickenham Stadium in London, March 15, 2009. REUTERS/Russell Cheyne (BRITAIN SPORT RUGBY) 

Ireland's Peter Stringer passes out from a ruck against Scotland during their Six Nations rugby match at Murrayfield, Edinburgh, March 14, 2009. REUTERS/Russell Cheyne (BRITAIN SPORT RUGBY) 

England's Phil Vickery (2nd r) is cleared from ruck by Australia's during their international rugby union match at Twickenham Stadium in London November 15, 2008. REUTERS/Russell Cheyne (BRITAIN) 

Ireland's Robert Kearney passes the ball out in a ruck during their international rugby test match against Australia in Melbourne June 14, 2008. REUTERS/Mick Tsikas (AUSTRALIA) 

Crusaders' Richie McCaw (C) secures the ball from the Sharks in the ruck during their Super 14 rugby match in Christchurch May 2, 2008. REUTERS/Simon Baker (NEW ZEALAND) 

Bolla Conradie (C), backed up by team mate Luke Watson of the Stormers from South Africa (6), passes from a ruck as Waratah players Josh Valentine (top 2nd R) and Lote Tuqiri of the Waratahs from Australia (top R) look on during their Super 14 rugby union match in Sydney March 17, 2007. REUTERS/Will Burgess (AUSTRALIA) 

Argentina's Nicolai Vergallo (C) passes the ball from a ruck during their friendly rugby union match against Leicester Tigers at Welford Road in Leicester, England February 11, 2007. REUTERS/Eddie Keogh (BRITAIN) 

Wales hold the ball in a ruck during their rugby union test match against Australia at the Millennium Stadium in Cardiff, south Wales, November 4, 2006. REUTERS/Eddie Keogh (BRITAIN) 

New Zealand's Chris Jack (L) tackles Australia's George Gregan at the base of the ruck during the rugby union Tri-Nations test match between the Wallabies and the All Blacks in Christchurch July 8, 2006. REUTERS/Simon Baker (NEW ZEALAND) 

Romania's Cosmin Ratiu (R) pushes the ruck during a rugby test game against Canada in Bucharest November 19, 2005. REUTERS/Mihai Barbu 

Wales' Lee Byrne (R) is tackled by Ireland's Brian O'Driscoll (L) during their Six Nations rugby union match at Lansdowne Road in Dublin February 26, 2006. Ireland won the match 31-5. REUTERS/Patrick Bolger 

Fabien Pelous of France looks for the ball amongst the ruck during their Six Nations rugby union match against Scotland at Murrayfield in Edinburgh, Scotland, February 5, 2006.REUTERS/Toby Melville 

Australia's Paul passes the ball out from the ruck during the first test match against South Africa of the Nelson Mandela Challenge Plate in Sydney. Australia's Jeremy Paul (C) passes the ball out from the ruck during the first test match against South Africa of the Nelson Mandela Challenge Plate in Sydney July 9, 2005. Australia beat South Africa 30-12. REUTERS/Will Burgess 

Jerry Collins from the All Blacks lies on the bottom of a ruck during the second test against the British and Irish Lions in Wellington. Jerry Collins from the All Blacks lies on the bottom of a ruck during the second test against the British and Irish Lions in Wellington July 2, 2005. New Zealand, inspired by brilliant 33-point flyhalf Dan Carter, overwhelmed a new-look British and Irish Lions with a record 48-18 victory on Saturday to take an unassailable 2-0 lead in the three-match series. REUTERS/David Gray 

All Blacks captain Umaga talks to McCaw during captains run at Westpac Stadium in Wellington, New Zealand. All Blacks captain Tana Umaga (R) talks to Richie McCaw during the captains run at Westpac Stadium in Wellington, New Zealand, July 1, 2005. The controversy surrounding Umaga and his involvement in the incident that caused his British and Irish Lions opposite Brian O'Driscoll's dislocated shoulder refused to go away on Friday. Umaga has been subjected to daily attacks by Lions management over the incident in which he and hooker Keven Mealamu upended O'Driscoll at a ruck, forcing the Irish centre to land heavily on his shoulder and be carried off in the second minute of the 21-3 first test loss. The All Blacks play the Lions in the second Test tomorrow. REUTERS/Anthony Phelps 

Argentina's captain Matias Albina (R) makes a pass from the ruck with Englands' Chris Bell close behind during Churchill Cup rugby action in Edmonton June 26, 2005. REUTERS/Dan Riedlhuber DR/KS 

British and Irish Lions rugby player Matt Stevens charges over a ruck during a public training session in Christchurch. British and Irish Lions rugby player Matt Stevens charges over a ruck during a public training session in Christchurch June 13, 2005. The Lions' next game of their New Zealand tour is against Wellington on June 15 in Wellington. REUTERS/Simon Baker 

Namibia's Emile Wessels leaps over Romania's Marian Tudori (19) with
Cristian Petre (L) and Augustin Petricheri (2nd R) attempting the tackle
during their pool A match of the Rugby World Cup 2003 at York Park in
Launceston October 30, 2003. Looking on is Namibia's Corne Powell (R).
Romania won 37-7. REUTERS/Simon Baker PP03110005

SB 

Pierre Hola from Tonga places the ball while on the bottom of a ruck during
their Rugby World Cup game against Canada at Wollongong Stadium, located 80
kilometres (50 miles) south of Sydney October 29, 2003. Twenty nations are
competing in the six-week tournament for the Web Ellis trophy. REUTERS/David
Gray PP03110005

DG/CP 

Canada's Winston Stanley passes from the ruck as Wales' Mike James (C) looks
on in the background during their match at the Rugby World Cup in Melbourne
on October 12, 2003. Wales defeated Canada 41-10. REUTERS/Adrees Latif
PP03100064

AL/CP 

A brothel promotions team member poses for a photograph at Circular
Quay in Sydney before a truck bearing the words "Fancy a Ruck" sets off
on a drive through city streets to advertise the brothel October 4,
2003. Inner Sydney city brothel Stiletto has joined other
establishments across Australia which are gearing up for an anticipated
bumper trade during the six-week-long Rugby World Cup which tourism
officials expect to attract at least 40,000 overseas visitors.
REUTERS/Will Burgess

WB/CP 

A brothel promotions team member poses for a photograph at Circular
Quay in Sydney before a truck bearing the words "Fancy a Ruck" sets off
on a drive through city streets to advertise the brothel October 4,
2003. Inner Sydney city brothel Stiletto has joined other
establishments across Australia which are gearing up for an anticipated
bumper trade during the six-week-long Rugby World Cup which tourism
officials expect to attract at least 40,000 overseas visitors.
REUTERS/Will Burgess

WB/CP 

A truck bearing the words "Fancy a Ruck" advertises a brothel while
driving through central Sydney as pedestrians look on October 4, 2003.
Inner Sydney city brothel Stiletto has joined other establishments
across Australia which are gearing up for an anticipated bumper trade
during the six-week-long Rugby World Cup which tourism officials expect
to attract at least 40,000 overseas visitors. REUTERS/Will Burgess

WB/CP 

FIJI 'S RAULUNI RELEASES THE BALL FROM A RUCK DURING THEIR
INTERNATIONAL RUGBY UNION TEST MATCH AGAINST SCOTLAND AT MURRAYFIELD
STADIUM IN EDINBURGH. 

Australia's Stirling Mortlock (3rd R) is tackled by Scotland's Gregor Townsend (2nd R) during their International rugby union match at Murrayfield in Edinburgh November 11, 2000.

JJM/PS/CLH/ 

South Africa's Thinus Delport leaps a ruck over All Black Mark Robinson (13) during their Tri Nations match at Jade Stadium, Christchurch July 22. South African players from left are Robbie Fleck,Percy Montgomery (rear) and Werner Swanepoel.The All Blacks won 25-12.

SB/HL 

South Africa's Robbie Kempson is restrained by team mates as he appeals to the touch judge for a penalty after coming up from a ruck with a head wound during their Tri Nations match against the All Blacks at Jade Stadium, Christchurch July 22. At left is De Wet Barry with referee Chris White (R) trying to calm players down.The All Blacks won 25-12.

SB/HL/PB