Top footballers are afraid to speak out against playing too many matches for fear of the impact it could have on their careers, the general secretary of global players' union FIFPro said on Friday.
Alex Phillips was speaking after FIFPro held a meeting in Amsterdam with 58 national player unions from around the world to discuss concerns over the way the sport's world governing body Fifa is managing global football.
The meeting came less than two weeks after the end of the first 32-team Club World Cup in the United States, a tournament hailed as a huge success by Fifa president Gianni Infantino but criticised by FIFPro for the demands it has placed on players already faced with a crowded schedule.
"Before the Club World Cup, I was speaking to some of the top stars and they were saying they hadn't had a rest for 'X' amount of time," Phillips said.
"One of them even said, 'I'll only get a rest when I get injured'. Others were resigned actually, and cynical about speaking up.
"Then you see some of the same players two weeks later having to record social media videos saying 'We think the Club World Cup is great,' because their employers are telling them to do it.
"You have this contradictory situation where players can't speak up. They are in an invidious position. They can speak up but it might have consequences."
FIFPro said that Fifa's recent focus on the Club World Cup in the United States was an example of the body ignoring many fundamentally more important issues facing players around the world.
"It is unacceptable for an organisation that claims global leadership to turn a blind eye to the basic needs of the players," FIFPro said in a statement, notably citing the "overloaded" match calendar, heat concerns at the Club World Cup and an "ongoing disregard for players' social rights".
FIFPro Europe filed a complaint to the European Commission last year accusing Fifa of abusing its position with regards to its handling of the international match calendar.
The summit hosted by the union on Friday came after it was left out of a meeting held by Fifa on the eve of the recent Club World Cup final.
Sergio Marchi, the Argentinian president of FIFPro, this week slammed Infantino's leadership of Fifa and accused him of running an "autocracy" in an interview with The Athletic.
Fifa hit back at FIFPro in a statement on Friday as it called for dialogue "with legitimate bodies that put player welfare first" and said it had tried unsuccessfully to get the union to attend its meeting in New York on July 12.
"Fifa is extremely disappointed by the increasingly divisive and contradictory tone adopted by FIFPRO leadership," the Zurich-based organisation said.
"This approach clearly shows that rather than engaging in constructive dialogue, FIFPRO has chosen to pursue a path of public confrontation," which aims to preserve "their own personal positions and interests."