What is Speed?
Sports Definition: Speed is the ability to move quickly across the ground or move limbs rapidly to grab or throw.
Speed is not just how fast someone can move, but is dependent on their acceleration (how quickly they can accelerate from a stationary position), maximal speed of movement, and also speed maintenance.
Movement speed requires good strength and power, but also too much body weight and air resistance can act to slow the person down.
Used correctly it's key to winning most games. Speed of thought, reaction and decision making also. Reaction time, movement time.
"Australia will fancy their chances of scoring tries against Ireland. It's in their DNA to do so"
It would be silly of Australia not to play to their strengths when they take on Ireland at Suncorp Stadium here in Brisbane on Saturday. Power up front, strong scrum, Michael Hooper and David Pocock in the same back row, creating havoc at the breakdown. Power and speed up front, allowing quick access to the all important ball for Will Genia and company.
Genia is key for Michael Cheika's side, when he plays well, Australia play well. He is a first-class decision maker. Controlled in thought and actions. Allow him time to dictate and bring those around him into the game and you are already on the back foot.
Bernard Foley and Kurtley Beale are key decision makers also, they can vary their game as required, experienced operators, used to operating at the red-hot coal face of International rugby.

Genia (88 Tests), Bernard Foley (55 Tests) and Kurtley Beale (71 Tests). Allow them dictate, Australia dominate.
Speed of delivery and execution allows Dane Haylett-Petty, Marika Koroibete plus Israel Folau to use their pace to devastating effect. Australia will fancy their chances of scoring tries against Ireland.
It's in their DNA to do so. Michael Cheika encourages his players to play what's in front of them. Power up front, breakdown twins, relay runners in the back line. All with speed of thought, delivery and execution. Ireland need to beware.
However, its not Super Rugby, it's an international Test game. It's different. Despite what some may say, it's a step up from what players are used to week-in-week-out.
Speed of thought and execution under pressure at Test level is completely different. How many times during or after a game do we ask or say "why did he/she do that?" "I can't understand why he/she took that decision".
So I guess its not just about speed, it's how it is used correctly and to best effect.
Listen to Michael Corcoran's live commentary on 2fm from 10.45am (11am kick-off) in the company of Donal Lenihan, or follow all three Saturday tests between Australia and Ireland with our live blogs on RTÉ Sport Online and the RTÉ News Now app.