Dr Nathan Gibbs, the former Roosters and Rabbitohs top-grade forward, recalls vividly his first game as club medico for the Sydney Swans.

''It was at the SCG in 2000 and I was trying to get to an injured player on the field,'' he said, the same role he anticipates playing in tonight's match against Collingwood at ANZ Stadium. ''I ran this circuitous route to avoid the ball, heading to empty space but suddenly it was filled with players. I was trying to get out of the way but in an instant I had about 15 players coming at me.''

Gibbs's problem was the same as the one which will confront NRL stars, such as Karmichael Hunt and Israel Folau, switching to AFL: the two codes are vastly different games, where the habits of one are alien to the other, skills praised with the Steeden are penalised with the Sherrin and the demands on the body are poles apart. As he says, ''It took me a while to realise the empty space is where they kick the ball.''

They do in rugby league as well - as in legendary coach Jack Gibson's SCG injunction, ''kick to the seagulls'' - however Gibson was referring to kicks for territory away from the opposition fullback and winger. AFL kicks are designed to land on the chest of a teammate. The kicker must find a man in space down field, allowing for the fact the ball will spend three to four seconds in the air, giving time for defenders to run to it. It may be a 35-metre kick over the heads of others, meaning a 30-metre punt is too short and a 40-metre one too long.

The standard attacking kick in rugby league is across the field from a halfback to a stationary winger and everyone must remain onside but in the AFL, as Gibbs says, ''Players come from 360 degrees. You can be hit in any direction. Players must have a depth of direction, while in rugby league, there are simply two lines.'' While Folau's vertical leaps make him look as if he has been fired from the ejector seat of a jet fighter, he will find himself spinning like an out-of-control weather vane as he is buffeted from all sides in the AFL.