Captains and leadership groups will take on more on-field responsibility this season as coaches are restricted to only one runner on match day.

The AFL has cut the number of runners from two to one as part of a bid to help clear up the field and improve the spectacle.

One senior coach now estimates messages will be reduced by 25 per cent, with the workload of the single runner rising considerably.

The runner will have to be supremely fit, with some coaches and managers raising concerns former players will no longer be capable of doing the job because a specialist athlete will be required.

Coaches have said their messages will need to be more tactically oriented because they cannot afford to waste time on matters such as interchange rotations.

While in recent seasons players have increasingly decided when to come off for a rest, some coaches believe there will need to be more consultation early in the season as all parties adjust to the cap of 120 rotations a game.

Coaches may also have to put greater faith in their senior players when scores are tight late in matches.

Port Adelaide captain Travis Boak said his club would be prepared for the change.

''That's another challenge for our leadership group but we definitely have the players there to do it,'' he said. ''Jackson Trengove is probably the one, and another is Alipate Carlile. They have been super in that [leadership] area.''

Boak said coach Ken Hinkley wanted his leadership group to act as an extension of his coaching.

''Ken really wants us to be a coach out there as well as being a player. The biggest thing Ken said to us last year about leadership was being able to stand up on game day,'' he said.

''That is still going to be the focus. You are going to get into different scenarios on game day and you have to adapt to that.''

The Power won five matches by 10 points or less last season as it vaulted into the top eight. It also won 15 last quarters, the second-best return by any club, with Boak confident his men can maintain their strong finishes even with fewer messages from the coach's box.

''You certainly do get a lot of messages out from your line coaches in different situations. It's something we will hopefully adapt to pretty quickly,'' he said.