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Along with the hooker, the loose-head and tight-head props make up what is known as the front row, which refers to their position in the scrum.
It takes a special breed of player to be effective in the front row. With the rest of their pack behind them driving forward, the front row is the epicentre of the scrum and the point where the two packs collide, literally head on.
To be successful, both props must be extremely strong in the neck, shoulders, upper body and legs, and they should relish head-to-head competition. England and British Lions tight-head Phil Vickery's taste in tattoos sums up the prop mentality. The 19st 9lb Vickery has oriental writing on one arm that translates roughly as "I will fight you to the death."
While stopping their side of the scrum from moving backwards, the props also support the hooker's body weight, allowing him or her to see and strike the ball when it is put into the scrum. In the lineout, props should be able to support or lift the jumper to prevent the opposition winning the ball.
Away from set pieces, props help to secure the ball when a player has been tackled, so it helps if they can combine their power with a degree of mobility. You’ll also often see them used as battering rams in attack, receiving short passes after a ruck or maul and hitting the opposition defence at pace in an attempt to occupy the defenders and make space for their own backs.
Strength, power, bravery, mobility
Jason Leonard (England and Lions), Syd Millar (Ireland and Lions), Wilson Whineray (New Zealand), Martin Castrogiovanni (Italy)