World Cup stars are at greater risk of injury due to the unprecedented demands of the congested calendar, global players' union FIFPro warned on Tuesday.

"FIFA World Cup 2022: The Player Workload Journey," highlights the lack of time available for footballers to rest between the end of domestic commitments and the start of the tournament in Qatar on November 20.

"After a packed first half to the current league season, the average preparation and recovery time for many players will be seven and eight days, respectively, about four times less than usual," FIFPro said in its report.

"This is likely to increase the risk of muscle injuries and mental stress."

This year's World Cup is the first to be played in the middle of the season in Europe, where most of the top stars are based.

As well as the absence of a break before the tournament, leading leagues will restart just days after the World Cup final, which takes place in Doha on December 18.

The report points out that the English Premier League will restart just eight days after the final, compared with a break of 26 days after the 2018 World Cup in Russia, and 34 days after the 2014 tournament.

"Significantly reduced preparation and recovery periods before and after this World Cup pose an ominous threat to player health and hinder performance optimisation," it said.

According to the report, which covers the period from July 12, 2021 to October 24, 2022, Liverpool and Netherlands defender Virgil Van Dijk played the most minutes of those analysed -- 7,597 in 78 games.

Van Dijk could come up against his former Liverpool teammate Sadio Mane when the Netherlands face Senegal on Monday, if the Bayern Munich forward is fit enough.

Mane, who won the Africa Cup of Nations with Senegal this year, has played in 93 games in the analysed period.

FIFPro has regularly voiced concerns about player workload since the Covid-19 pandemic.

However, the report also raises concerns that certain national teams could be hindered at the World Cup by a lack of football.

Hosts Qatar, whose players have spent the past six months in a training camp, have only played in national team friendlies in that time.