New season, new rules. Nine law and interpretation changes the AFL believes will stimulate free-flowing football and more one-on-one contests will be in effect when the 2019 season starts at the MCG tonight.

The truncated preseason gave us a small taste of footy's revamp, providing a glimpse of how the coaches and players have been navigating the new rulebook.

The long kick-outs

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One of the most noticeable changes is the way teams kick in after the opposition has scored a behind.

The player who takes the kick can now choose to play on without kicking the ball to themselves.

Their opponent standing the mark is also required to stand 5 metres further back than they previously did.

It's hoped this change will speed up play by encouraging teams to play on and kick long.

However, the preseason showed that short kicks to the pocket remain a popular and often effective option.

A similar thing happened when an enlarged goal square was trialled in three VFL matches late last season. There were 51 kick-ins during those trials, resulting in just one score.

The season-long VFL average was a score from kick-in 6.8 per cent of the time.

Changes to the kick-out are among the rule tweaks for the 2019 season. ( AAP: Tracey Nearmy )

So, will we see more coast-to-coast goals in the AFL this season? Perhaps not, and it's a simple matter of geometry.

To kick the ball a long way, it must stay in flight for a long time. This allows defenders a greater opportunity to make position.

Look at this clip of North Melbourne's Marley Williams taking a short kick-in to a pocket.

In total, the ball is in flight for just over a second. At an average running speed of 20 kilometres per hour, a defender would be able to cover about 6 metres while the ball is in flight.

That's a defensive coverage circle measuring about 113 metres squared.

While that might sound like a lot, the area of the MCG is approximately 17,000 metres squared.

A team would need at least 150 players to provide total zonal coverage across a ground of that size.

Now consider this example.

Here, Richmond's Jayden Short plays on before launching a long kick to the wing. The ball spends about four seconds in flight, and reaches its destination about seven seconds after Short's intention to play on becomes clear.

In this instance, a defender travelling at 20 kph would be able to cover about 22 metres while the ball is in the air, giving him a coverage area of 1,551 metres squared. That's more than 10 times the area he could cover when reacting to a short pass.

Theoretically, it only requires six defenders to cover the entire defensive half of the field if they each have four seconds in which to react.

Even accounting for the time needed to read the ball off the boot, it would be rare for at least one not to get to the fall of the ball.

At jogging pace, defenders are generally able to cover long kick-ins quite easily, turning them into contested marking battles.

Smart sides may therefore choose to ignore the invitation to play on and kick long, and instead stick to a slower and more deliberate transition from their back half.

6-6-6 starting positions

The other major rule change is the mandatory alignment of teams at centre bounces, requiring them to have six defenders and six forwards within each arc, and six midfielders between the arcs.

The impact of this change is fleeting, affecting only the few seconds after each centre bounce. It's anticipated that will be enough time to give teams a better chance to convert a clean clearance into a forward line mark.

Preseason data shows scores from centre clearances increased slightly. However, some teams have already been experimenting with the starting positions. Keep your eye on the right of the screen in the following clip.

See the Hawthorn player race off their defensive 50m arc to attack the centre contest?

Here the Hawks are aiming to outnumber their opponent to gain first use in the midfield, while relying on the geometric principles we discussed earlier to mitigate their numbers disadvantage in defence.

If this match was being played at the MCG, the player would only have had to run an extra 5.5 metres to reach the contest from the top of the arc than from the edge of the centre square.

That means he'd only take about a second longer to impact the contest than he would have been able to under the old rules.

A somewhat more conservative tactic has been tested by clubs including Sydney and Adelaide. Look at the bottom of the screen in this next clip. What's the Gold Coast wingman pointing to?

He's just noticed his opposing wingman has abandoned him. The Swans player has dropped as close as possible to his defensive 50, intending to sprint back as a spare defender as soon as the ball is bounced.

Again, the extra distance he'll need to cover to make position is only a minor impediment. It'll take him just two or three seconds to transform from a fake winger into a plus one.

In truth, the 6-6-6 formation may be more of a mild annoyance to coaches than a true game changer.

Teams are already seeking ways to revert to their preferred structures as quickly as possible, while minimising their exposure to risk.

Expect to see more innovative workarounds as the matches become more meaningful.

Penalty upon penalty

The change that is causing the most consternation is the one that perhaps the most benign on paper: the reinterpretation of the 50m penalty.

The new rule allows players to quickly play on while the penalty is being advanced.

This change has sparked discussion about unintended consequences, as successive soft 50m penalties have resulted in easy goals.

To exploit the new interpretation, players have been running at opponents to draw further penalties.

The obvious solution would be to steal an idea from rugby league, where penalties are only invoked against offside players when they are directly involved in the play.

It seems likely the AFL will need to pursue a similar path, by more sensibly defining "impediment".

The spectacle of mass confusion and repeated umpire intervention won't be tolerable for anyone, even the broadcasters who'll have more time for ads through the occasional extra breaks after goals.