London - English rugby chiefs on Monday announced an action plan alongside a report showing a rising number of injuries during matches, with concussion making up nearly a quarter of the total.

The Professional Rugby Injury Surveillance Project, covering the 2016/17 season, said the incidence of match concussions rose for the seventh consecutive season.

And it suggested a World Rugby directive to increase sanctions on tackles and take a zero-tolerance approach to contact with the head made "no difference" to the incidence of all injuries and concussion.

"We would like World Rugby to give consideration to thinking about reducing the legal height for the tackle," said Rugby Football Union (RFU) medical services director Simon Kemp.

"There's very little margin for error with the permitted height of the tackle at the line of the shoulders. It's for World Rugby to consider and we know they're doing that at the moment."

In the 2016-17 Premiership season there were 3.8 injuries per match (1.9 per team) on average. The average severity of match injuries - the time taken to return to play - was 32 days.

The report showed 47 percent of all match injuries are associated with the tackle, with an almost equal split between tackler and the ball carrier.

And it said the incidence of training injuries also rose.

Nigel Melville, the RFU's director of professional rugby, said the legal height for a tackle had become a "grey area" that was interpreted differently by referees.

"We want to work with the players, the professional clubs and World Rugby to build a much better body of knowledge about this, so we make better, more informed decisions," he said.

An eight-point Professional Game Action Plan on Player Injuries, developed by the RFU, Premiership Rugby and the Rugby Players' Association, was announced alongside the publication of the injury project.

As well as addressing the tackle height, the plan vowed to undertake or continue research in player load, training injury risk and the impact of artificial grass pitches.

Premiership Rugby's Phil Winstanley said injuries were not just a problem for English rugby.

"This is also a world game issue and we look forward to engaging with World Rugby to identify solutions which benefit all," he said.