Ruckmen will be banned from making contact at throw-ins and ball-ups, and umpires will no longer be instructed to bounce the ball at stoppages around the ground as part of a series of rule changes for 2013 approved by the AFL Commission.

But there will no change to the interchange system next season after the commission overruled the laws of the game committee's recommendation that a cap on interchanges be introduced.

The laws committee, chaired by AFL football operations manager Adrian Anderson, had recommended that a cap of 90 interchanges per game (20 per quarter, three during each break and one substitution) be brought in with the twin aims of lowering injury-rates and reducing congestion.

The cap was to co-exist with current three-and-one interchange system.

But at its meeting on Monday the commission decided to wait another 12 months before making the change.

A cap on interchanges will once again be trialled in next year's NAB Cup, and the commission is then expected to rubber-stamp its introduction for the 2014 premiership season.

"The commission is an independent body that takes a 'big picture' approach in overseeing the laws of our game," AFL chief executive Andrew Demetriou said on Tuesday.

"It has decided to assess another season with the current interchange rules in place, plus review the further trial of a cap in the 2013 NAB Cup before deciding whether to implement a change.

"This decision demonstrates the important oversight role the AFL Commission plays and underlines the robustness of the governance arrangements that apply to all significant long-term decisions affecting how our game is played."

Interchange numbers have increased dramatically in recent years and, despite the introduction of the three-and-one system, teams averaged 131 interchanges per game in 2012 - up from 81 five years ago.

With that in mind, it had been widely speculated that the commission had approved a cap of 80 interchanges.

But the one-year delay is a win for the coaches, who told the AFL they needed more time to plan for such a major alteration to the interchange system.

However, the commission has approved a number of other rule changes.

From next season umpires will only bounce the ball to start quarters and after goals.

"Throwing the ball up around the ground will enable the ball to be cleared quicker from congestion and will also make it easier for umpires to detect infringements," Anderson said.

When it comes to the new ruck rules, which were trialled in this year's NAB Cup, no contact will be permitted until the ball has left the umpire's hand.

"With this rule change we want to encourage rucks to play the ball and not the man as well as facilitate cleaner hit-outs to advantage and to assist clearance rates," Anderson added.

The AFL has also tightened the "forceful contact below the knees" rule.

A free kick will now be paid against any player "who makes forceful contact below the knees of an opponent".

"Clubs and players have adapted well to the free kick for sliding knee- or feet-first this season and we have extended this to protect players from any forceful contact below the knees," Anderson explained.

"In addition to the injury-prevention benefit, this change is also designed to encourage players to keep their feet and to assist in reducing congestion."