Dive Pass vs Standard Pass

Let's look at the dive pass. In order to investigate the effectiveness of the dive pass, which is primarily used by halfbacks, a small study was conducted using several first-grade halfbacks. In this study a dive pass was compared to a standard clearing pass in terms of velocity at release, time to a target 10 metres away, and accuracy. It was found that the velocity at release was essentially the same, as was time to target. Accuracy was found to be slightly less for the dive pass.

Based on these findings it would seem that the only real advantage of the dive pass is that it is more effective at avoiding oncoming defenders, due to the movement of the halfback. Therefore this seems to be more of a tactical manoeuvre than an enchancement of the pass itself.

First let's look at velocity. The primary reason for the lack of an advantage is that in a standard pass the halfback is able to sequence their body segments and transfer their momentum to the ball. In the dive pass the halfback is not able to do this as effectively bacause they are airborne, and therefore unable to sequentially stop each segment, which in turn limits the amount of transfer of momentum to the ball. To compensate for this the halfback uses the initial velocity gained from the dive to give the ball some initial velocity prior to the acutal passing motion of the arms. Time to target is therefore no different because the velocities are quite similar.

As for accuracy, we need to look at the next principle, which is an extension of principle 3 (which is apply forces (i.e. ground reaction forces) in the direction of the desired change of motion (forward, sideways, up, down, etc.))
EXTENSION OF PRINCIPLE 3:
When trying to achieve accuracy, have as many segments moving in the desired direction of the movement as possible while limiting any motion in other directions.

During the dive pass there is a much greater potential for movement out of the line of motion of the ball, due to the high unstable position the halfback is in. One thing the above principle doesn't say is that it is very important to have a solid base of support when trying to achieve accuracy. During the normal clearing pass the halfback is usually fairly low to the ground and has his legs spread wide. This is a very stable position and gives a firm base from which to direct the necessary forces on the ball. It also allows for more effective transfer of the ground reaction forces than during the during the airborne phase of the dive pass. Therefore, the dive pass can be much more effective when under pressure from opposition, while the standard pass is generally more accurate method of passing the ball.

Taken from THE PHYSICS of FOOTIE, SMART TRAINING for RUGBY.

hm... the physics side of rugby.