What is Rugby?

This article from Wikipedia discusses Rugby Union, of which the CSULB Rugby team plays.

Team positions: Props

The role of both the loose- and tighthead props is to support the hooker in the scrum and to provide effective, dynamic support for the jumpers in the line-out. Along with the second row, Props provide the main power in the push forward in the scrum, and it is for this reason that they need to be exceptionally strong. Under modern rules non-specialists are not allowed to play as props (or hooker) as specialist skills are required to assure the scrum does not collapse, a situation which can be very dangerous, and potentially lethal. If there are not enough props or hookers on either team (and no replacements are available), uncontested scrums will be set.

A tighthead prop is so called because they pack down on the right-hand side of the scrum and so their head fits between the opposing loosehead prop and hooker. In contrast, the loosehead prop packs down on the left-hand side where their head is outside that of the opposing tighthead prop. Although it may look to the neutral observer that the two positions are quite similar (and some players have the ability to play on both sides of the scrum), the technical challenges of each are quite different.

The laws of the game require the tighthead prop to bind with his right arm outside the left upper arm of his opposing loosehead prop and similarly they restrict what the loosehead prop can do with his left arm. Although the scrum half may put the ball in on either side of the scrum, he is unlikely to choose the tighthead side because otherwise the opposing hooker would be between him and his own hooker. Hence, the laws implicitly require the loosehead prop to be on the left side of the scrum.

Props are also in the position of being able to direct the movement of the scrum in moving side to side to prevent the other teams scrum from "wheeling" the set scrum and forcing another "put in" from the opposing side

Notable loosehead props include Jason Leonard (England and Lions), who is also one of a rare breed who can prop on either side, Tony Woodcock (New Zealand), Charlie Faulkner (Wales and Lions), Os du Randt (South Africa), Duncan Jones (Wales) and Andrew Sheridan (England and Lions).

Notable tighthead props include Adam Jones (Wales), John Hayes (Ireland and Lions), Graham Price (Wales and Lions), Phil Vickery (England and Lions), Carl Hayman (New Zealand) and Olo Brown (New Zealand) and Peter Clohessy (Ireland.).