The forward pass question

Now that South Africa are using the television match official to check on the validity of tries, the matter of the forward  pass has now become interesting.

There were two cases of referral by a referee to the TMO regarding forward passes in the very first weekend of the Currie Cup - one in Bloemfontein and one at Newlands. Both have evoked much talk, but especially the one at Newlands.

There have been questions to the Duty Ref on the South African Referees' website. It is a good time to talk about it and to get things clear in our minds, because it is not as simple as it looks and is all tied up with science which is not at all simple to lots of people.

We shall start at the law which does not refer to a forward pass at all but to a forward throw. It is the act of throwing forward not the act of catching forward which counts. It is a forward pass, not a forward catch.

The scientist will tell you that unless the passer is stationary it is extremely hard to prevent the ball from travelling forward. If we were to stop play every time the pass from a moving player travelled forward we would kill rugby.

We have a scientific viewpoint from Case Rijsdijk and then a telling set of clips from the Australian Referees.

Keep an open mind.

First the law.

Law 12 DEFINITION THROW FORWARD

A throw forward occurs when a player throws or passes the ball forward. ‘Forward’ means towards the opposing team’s dead ball line.

It is about the act of throwing, not the act of catching.

Now read science according to Rijsdijk

The Forward Pass

If a ball is thrown diagonally backwards by a stationary player, the ball has actually got two speeds, one directly backwards, and one towards the touch-line. This means it travels across the field of play (from touch-line to touch-line) at a speed U and backwards (away from the opponents dead ball line) at a speed V. Put another way, a spectator standing on the touch-line would see the ball travelling backwards at V, whilst a spectator standing behind the uprights would see the ball traveling across the field at U.

Consider a player, P, running at speed S towards the opponents' goal-line with the ball. The instant he passes the ball, it also has speed S forwards

Now consider two players, A and B, with B 1m behind and 6m across the field from A. Assume also that they are facing the opponents' dead-ball line. If they are both standing still, and A passes the ball to B in 1 sec, then its speed backwards is 1 m/s and 6 m/s across the field of play.

Now assume that both players are walking forward at 1 m/s, and A again passes the ball to B in 1 sec. As the ball leaves A’s hands, it has a speed of 1 m/s backwards, as before, but because A is moving forward at 1 m/s the ball also has this speed. This means the ball has zero speed in the forward direction and it actually travels directly across the field of play and does not go forward. However players A and B and the referee (a good one who keeps up with play!) are all moving at 1 m/s, so to the referee the ball is passed backwards as before, but the spectator sees the ball moving directly across the field of play.

Let’s now assume that the players and the referee are moving forward at 3 m/s, and the ball is again passed from A to B in 1 sec. As the ball leaves A’s hands it has a forward speed of 2 m/s (3 – 1) m/s. The referee sees the ball passing backwards from A to B, as before, because he is moving with the players. But the spectator cries foul: he sees the ball moving forwards across the field of play at 2 m/s!

For the spectator to see a pass which he judges not to be travelling forward, the ball must at least have a backward component of 3 m/s (the ball would then travel directly across the field of play). This means it covers the back distance of 1 m between A and B in 1/3 sec. In turn this means the ball reaches B, covers the 6 m across the field in 1/3 sec and so the speed across the field is now 18 m/s (6 divided by 1/3). Passing a ball at this speed whilst running at  3m/s (11 km/h) is not easy! And 11 km/h is not fast.

Normally a wing, or other back, running at a fair speed, say 5 m/s (18 km/h or running 100m dash in 20 secs) would need to pass the ball to B at over 130 km/h for the pass not to travel forward. The ball would need a backward component of 6 m/s, and so the back time would be 1/6th sec and the speed across would be 36 m/s. Of course if B were to move further back, then the passing speed would decrease, but then it would have to be increased if B moved away (across) from A. A really fast back, probably running at say 8 – 9 m/s (or a 100 m dash in 11 – 12 sec) would have to pass the ball to his team-mate at nearly 220 km/h for the pass not to travel forward.

These things become particularly clear to spectators when the ball is passed between running players as they cross the 10 m, centre or 22 m line. It is fair to say that virtually all passes between running players will travel forward since the balls travels towards the opponents dead ball-line during the pass. This is what is seen by stationary observers, spectators, but not be the referee who is running with the players.

If passes of that kind were considered forward passes we would very seldom have passes that were not forward.

I would like to suggest the law read:

When passing the ball from player to player, the player passing the ball, passer, must be in front of the player receiving the ball, receiver, at the moment that the ball leaves the passer’s hands.*

Simply put passer to be in front of receiver

Another interesting, related, observation.

Often when a player is about to be tackled he will try and pass the ball. In the tackle the passer is likely to be slowed or brought to rest (if tackled hard). The referee also slows or stops and the ball then has to carry on at its original speed (since it has just left the player's hands) and the player is deemed to have lost the ball forward: scrum/advantage!

That's what Rijsdijk says.

Now look at the You-Tube examples: http://fr.youtube.com/watch?v=RgMlDy2jP9s.

You see rugby football is meant for intelligent people! You will also see that the lines are irrelevant when it comes to judging a "forward" pass. You will also see from the scientist that the danger for the TMO is judging while stationary an action on the field when people, including the referee, are moving.

There is always an important refereeing principle to remember: if an offence/infringement is not clear and obvious play goes on.