Sunderland striker Jermain Defoe feels the club's struggles this season were partly caused by a poor fitness regime under previous boss Dick Advocaat.
Advocaat quit his role eight games into the Premier League season, after guiding them to safety last summer, and although Sunderland remain in deep relegation trouble, their performances have improved since the arrival of Sam Allardyce as manager.
Defoe's form has also improved since Allardyce took over last October, and he hopes to add to his 16 goals over the last five games of the season, starting at home to Arsenal on Sunday.
The Black Cats are still in the relegation zone, but they are only one point adrift of 17th-placed Norwich and still have a game in hand on Alex Neil's side, who they beat 3-0 last Saturday.
"It's happened because of the start of the season. We just weren't good enough and we weren't fit enough," Defoe said in The Journal.
"If you look at the fitness stats now - the running stats and the high intensity stats, that side of it - we were so far off, so far off where we are now. Look at the [opening day] game against Leicester - we were blown away. It was difficult.
"Now it's like a different team. The first thing the manager [Allardyce] said when he came in, we had a meeting and he said, 'You're not fit enough.' He said, 'I'll get you fit and that's all you need' because we've got top players and internationals.
"But if you can't run, how are you meant to perform for 95 minutes?"