Daniel Gabbidon has admitted to Sky Sports News that effort levels at West Ham have not been high enough this season.
The Hammers face a daunting task in avoiding relegation as they are currently eight points shy of safety after a dismal season that has seen former boss Alan Pardew depart and reports of dressing room rifts proliferate.
New manager Alan Curbishley has also come under considerable pressure but Gabbidon believes that a drop in effort from the players at Upton Park is responsible for the London club's struggles.
"Last season we were a different team, we worked so hard to win games, everyone was 110 per cent and maybe this season that hasn't been the case. We have been more 90 per cent," Gabbidon told Sky Sports News.
"Obviously there are only a few teams that can play at 90 per cent and still win games, we have to be at 110 per cent to beat most teams and I don't think that has happened enough this season and I think that is why we are where we are."
Gabbidon also hinted that complacency may have played a part in West Ham's troubles after a tremendous campaign last season that saw them finish ninth in the league and come within seconds of winning the FA Cup.
"At the start of the season we had our aims. We wanted to win a couple more games, get a couple more clean sheets than last season, whereas last season all we looked at was staying up and seeing where we go from there.
"We seemed to do really well with that strategy, and the start of this season was a bit different as the expectations were a bit higher, and it just didn't happen so we have definitely underachieved as a team.
"To be bottom of the league is not good enough."