Rule changes have made football faster than ever before. Can the players’ hamstrings handle it?

Five hamstring injuries within 24 hours during round two have raised questions about the impact on player availability as game speed increases due to AFL rule changes.

The concerns centre on the amount of high-speed running required from players because there are fewer stoppages after the introduction of the last-touch and ruck rules and more transition running.

Richmond veterans Tom Lynch and Toby Nankervis, Gold Coast’s Christian Petracca, Adelaide’s Callum Ah Chee and St Kilda’s Anthony Caminiti all finished on the bench after hurting their hamstrings in their matches.

Ah Chee’s injury was a recurrence of the one he suffered representing Western Australia in the State of Origin game in February. He is likely to miss six matches. The other clubs were more hopeful of shorter absences from their injured players.

Physiotherapist and injury analyst Libby Birch says the impact may be felt all season as players need time to adapt their bodies to the frenetic way in which the match is now played, although club high-performance officials told this masthead they were taking a “wait and see” attitude before asserting this season to be different to previous years.

Birch, who has played in four AFLW premierships, said the spike in transition running had gone beyond what anyone predicted, and therefore some players would not have done high-speed running at training at the level required to avoid hamstring injuries in such a ballistic game.

“High-speed running has a direct correlation to hamstring performance and injury risk,” Birch argued.

“High-performance teams have an algorithm for how much high-speed running you do to expose the body and the hamstring to the load.

“It has been impossible to predict the speed of the game and how much it has changed year-on-year; therefore we have seen a huge spike in high-speed running numbers that the players have not been exposed to.

“That is not the fault of the high-performance team. Who would have predicted the speed of the game?”

High-performance officials this masthead spoke to on the condition of anonymity were cautious to draw a conclusion between the round’s injuries and the change in the speed of the game.

One official said clubs were obviously keen to attack and had been conditioned accordingly with the impact of managing five players on the bench rather than the sub a more uncertain variable.

Both Petracca and Ah Chee’s injuries occurred when the game forced their body into an unusual mechanism, while Nankervis and Lynch are both veterans. Lynch has a broad injury history.

Birch said high-performance practitioners knew to make players run at a high speeds during training to condition the body in a controlled environment in what was described as using “sprinting as a vaccine”.

But the leap in game speed has taken the amount of high-speed running to a place very few predicted. Players also had less time to rest because there were fewer stoppages and the times when they need to accelerate had increased.

“It might not be until next year that we see the athletes have adapted,” Birch said.

There were 17 players listed as needing tests or missing games due to hamstring injuries heading into round two, including Sydney superstar Isaac Heeney, who missed Thursday night’s loss to Hawthorn because he injured his hamstring in round one.

An additional five were added to the list by Saturday night. Hamstring injuries have always been the major reason players miss matches with six to seven players per club suffering hamstring injuries season year on average.

Meanwhile, the AFL is working through the timekeeping issue which arose before half-time in the Giants v St Kilda match on Saturday.

The time clock which appears on the coverage suddenly dropped from 30 seconds remaining to being zero seconds left after St Kilda’s Max Hall kicked a goal on the brink of half-time.

The Giants were told during the third quarter that no time was lost from the game, however the AFL will investigate to determine the issue after the countdown clock also stopped working during the final quarter of Friday night’s match between Adelaide and the Western Bulldogs.

Keep up to date with the best AFL coverage in the country. Sign up for the Real Footy newsletter.