B J Botha the Ulster Prop was pictured by John Dickson in these images completing a text book big hit tackle. Its truly frightening!
The fact that its text book implies that there are similar sets of circumstances that occur in tackle after tackle.
Player A runs into player B and we can analyse whats happening.
On one level the players are peforming tackles according to the laws of the game.
The IRFU laws book defines a tackle as “A tackle occurs when the ball carrier is held by one or more opponents and is brought to ground. A ball carrier who is not held is not a tackled player and a tackle has not taken place. Opposition players who hold the ball carrier and bring that player to the ground, and who also go to ground, are known as tacklers. Oppositions players who hold the ball carrier and do not go to ground are not tacklers.”
The rules are available at www.irishrugby.ie.
The professional players will tell you, the really big tackles happen when you or your opponent are least expecting it. The players on the recieving end have lost concentration or are so caught up in what they are trying to achieve that they have not noticed a player setting up to tackle them.
When a big hit happens it is spectacular. But there alot more standard tackles, which all require adherance to the rules, shoulder charges are allowed whenen chasing for a loose ball, although use of the elbow is not allowed.
THE PROF:
The Science Behind the Tackle:
Derrick Crothers a Belfast Harlequins Player is Professor Emeritus in Theoretical Physics at Queens University and we were delighted to discover that he has a personal interest in science in rugby and actually published two papers on the topic in 1992. They were called Mathematics in sport I and II.
He lent us a copies of them and it makes for fascinating reading.
Here’s as deep as we were able to go. 1st – Newton’s laws and coded sequences are used to explore sport mathematically. This includes classical mechanics; linear and angular momentum, work, impulse, kinetic and gravitational energy, simple harmonic motion, friction, rolling, rotating frames, Eular angles, and projectiles. Mathematical tools used are differential and integral calculus, vectors and vector spaces, dot and cross products, etc etc!
In rugby the spin hand pass and the spin torpedo kick are used to achieve greater accuracy and length
In rugby the try conversion may be taken anywhere on a straight line parallel to the touchlines and through the place of touchdown. It is sensible to choose the position which maximises the solid angle projected by the posts, so that maximum error in the kick may be tolerated.
Reading Derrick pamphlets is fascinating and shows the depth of thinking that a rugby player must use to complete a game. We may not be considering mathematical equations when we make tackles or kicks, but we know that the angle with which we hit a player in tackling allows us to wrap the hands around the body, or that it will allow us to tackle high and slip the grip down then to the ankles. We know that getting our centre of gravity down low when bridging a ruck is critical to protecting from a turn over ball. We know that the angle with which we enter the scrum is critical.
Their is massive concentration required here. But with all this concentration and knowledge there will be times when we get it wrong and find ourselves on the recieving end of a big hit! Equally we will get it right and put in a big hit!
Science can be used to describe these tackles. For example, player A runs into player B the ball carrier, the velocity with which the two players collide effects the outcome, if player A and player B are the same weight and player A is travelling at a greater speed than player B then player B will be pushed backwards by player A
This is expertly demonstrated by B J Botha in the pictures although he looks to be considerably heavier than the opposition player.
You can visually see the importance of the angle of BJ. Both players will be hearing sound on the impact, and there is also crumpling of the body. Both players feel the impact. The benefit to the tackler is that very often the tackled player experiences varying degrees of loss of control of the ball. Very often the ball will be knocked forward or fall away from the tackled player. Psychologically the tackled player may be impacted. He may not be as psychologiacally keen to carry the ball forward should he recieve another impact.
Lets just say, the angular momentum ( r x J = r x (mvf – mvi) of B J was perfect!
