Rugby is a multi directional contact sport. It involves strength and power, agility, speed and mobility. You go forward to score but are constantly running backwards then to the side then backwards again (depending on how good your team is). It requires the player to run at high and near maximal speeds and then either stop and change direction or even receive impact requiring a high amount of muscle control. Why do body builders not make the greatest rugby players, after all these guys can lift BIG! It goes like this, our bodies have three primary planes of movement: forward, side and rotational. Throughout the course of a match a rugby player will exhaust all three planes; they have to efficient in all three planes.