THE AFL should uncap interchange rotations and let the sport naturally evolve rather than introduce radical solutions to congestion, one assistant coach says.

The interchange proposal comes in direct contrast to what's being considered in ongoing discussions about the state of the game, but statistics back up the call.

Another Competition Committee meeting is slated for July 26, following every club's general manager of football discussing the topic – among other things – at AFL House on June 29.

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The AFL first capped rotations at 120 for the 2014 season before limiting them to 90 for 2016, coinciding with the five-year substitute rule being ditched.

That substitute experiment is credited as kick-starting the demise of the back-up ruckman, while Sydney's 2005 premiership coach Paul Roos dubbed it "the worst rule ever brought into footy" in 2015.

The likes of Essendon coach John Worsfold and retired great Nick Riewoldt this year called for rotation reductions of 60 and 40, respectively – and that is one option being considered.

But 2016 Brownlow medallist Patrick Dangerfield and five-time All Australian Scott Pendlebury are two high-profile voices against a further cut.

Former League football boss Adrian Anderson, then the Laws of the Game Committee chairman, blamed increased interchange use for problems plaguing the game eight years ago.

"The use of interchange has created more congestion, more stoppages (and) more defensive pressure and has contributed to a drop in disposal efficiency," Anderson said in 2010.

The AFL assistant coach who spoke to AFL.com.au has tracked relevant statistics since Anderson's assertion, made at the announcement of the new substitute rule.

His research, using Champion Data figures, illustrates that the contested possession rate – which represents congestion, in that it measures the percentage of ball won in a contest – has spiked since the changes.

Tackle numbers, admittedly just one element of defensive pressure, were also above pre-cap levels in two of the past three seasons, although they have dropped to a five-year low in 2018.

Disposal efficiency bettered the 2010 standard in only two seasons since and is worse this year than then.

"The theory behind it is if you tire players out, they will stay spread out, but what happens when players get fatigued, they creep in to where the ball is," the coach said.

"It's a reverse – they get closer to the ball, they don't spread away."

Tracking congestion in the AFL, 2010-18

YEAR INTERCHANGE STRUCTURE AVE INTERCHANGES % CONT POSS TACKLES THROW-INS, BALL-UPS DISPOSAL EFFICIENCY 2018 Four, 90 cap 94.1 38.8 65 61.3 72.2 2017 Four, 90 cap 95.2 37.2 68 61.2 73.4 2016 Four, 90 cap 95.5 38 69.8 61.9 73.5 2015 Three + one sub, 120 cap 118.4 37.6 65.6 70.7 73 2014 Three + one sub, 120 cap 117.3 38.2 66.3 66.9 72.4 2013 Three + one sub, uncapped 133.3 39.3 63 62.6 72 2012 Three + one sub, uncapped 130.9 39.3 63.7 63.8 72.4 2011 Three + one sub, uncapped 118.2 40.4 68.9 64.4 72.1 2010 Four, uncapped 117.4 36.6 67.6 61.1 73.1

The percentage of contested possession represents congestion, in that it measures the rate of ball won in a contest

Interchange numbers include quarter-time and injury/blood rule moves, which typically add up to about 10 changes

Not one year since Anderson oversaw the interchange modifications in 2010 were the number of stoppages per game lower than before them.

Making it more interesting is that there were huge increases in holding-the-ball (48.8 per cent) and deliberate out-of-bounds (113 per cent) decisions last year compared to five seasons ago.

"We're trying to artificially reduce (stoppages), when if we umpired the game the same way we did in 2013, they would be through the roof," the assistant coach told AFL.com.au.

"As a game, we've made some changes that have contributed to congestion and the capping of the interchange is one of those – and the numbers reflect that.

"I think rotations should be uncapped. If you want to rotate 20 times, rotate 20 times. If you want to rotate 150, rotate 150.

"From my experience, the optimal number as a club, to make sure you've still got control over it, is 135 to 140."

There have been 132 extra holding-the-ball free kicks up to round 16 compared to the same stage last season, but 16 fewer deliberate out-of-bounds verdicts.

AFL.com.au's coaching source instead believes the way teams are choosing to play the game is the major cause of congestion.

"We're in a copycat league and we've followed the last two premiers," he said.

"The Bulldogs were a heavy handball team around the contest and put numbers around the contest, while Richmond plays an extra forward that comes up to the stoppage.

"It's mostly (Kane) Lambert who plays that role, and they play an extra inside the stoppage as well."

Lambert's pressure has been a crucial part of Richmond's revolution. Picture: AFL Photos





University of South Australia professor of exercise science Kevin Norton was a paid AFL consultant for 14 years up until 2013, researching players' on-ground movement.

One of his recommendations back then was for interchange rotations to be slashed to 40 – or even as low as 20 – but he has softened his stance on that.

Norton, who has also consulted for rugby union and rugby league, told AFL.com.au that coaching tactics and player fitness eventually adapt to any interchange restrictions.

"The interchange rule is essentially exhausted and so we might need to go to zoning, lower player numbers on the field or other options," Norton said.

The bemoaning of AFL clubs increasingly drafting athletes over 'natural footballers' will accelerate if further interchange limitations or starting points come in, according to Norton and the coach.

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One rule change the Competition Committee is considering – and has included in club trials – would see sides field six players in the three zones of the ground at centre bounces and stoppages.

The assistant coach argues starting points are irrelevant at centre bounces – the game's "lowest density stoppage" – and sees a significant downside to them at other stoppages between the arc.

"I hope the people making those changes have watched a lot of VFLW footy and TAC Cup and seen the true impact of it, because it's a big change from the way our game's been played," he said.

"What the VFLW clubs have found is the girls who play the deep forward or deep back roles do a lot of shuttle runs up the ground.

"Then there's a stoppage, so they go back inside 50, then they go back up the ground again – and they're not getting anywhere near the ball while this is happening.

"You're going to need some really fit players to be able to handle that, because we still want players to get involved in the play … so that will be a challenge."