Lawrence Dallaglio fears England's rugby union World Cup victory may never happen again unless the strain on players is reduced. Dallaglio quit international rugby on Tuesday and England coach Sir Clive Woodward may follow over a reported row about having more time with his team.
"I'm unsure whether we have the right structure to allow our players to be successful," said Dallaglio.
"The World Cup was a little bit of a one-off."
He added: "Clive fought so hard to get the necessary working days and the timing of the tournament was perfect."
"Playing internationals while trying to run a domestic competition and the way the season runs until May before some players then have to go on tour are not conducive to career longevity.
"We are already seeing a number of injuries to high-profile players as a result of the number of games they are playing.
"It's an issue that needs to be addressed.
"We all want to play for our club and countries but the ferocity and intensity of the game in this part of the world is such now that people must take a serious look at the fixture list.
"Mentally and physically it is very demanding. Unless you're managed properly you end up staying on the treadmill until you decide to jump off."