Paul Lambert says it took him and his coaching staff as long as six months to bring Norwich City's squad up to their fitness levels when they took over at Carrow Road.

City's never-say-die attitude, exemplified by Monday's stunning late, late winner by Simeon Jackson against Derby, has played a major role in taking the team to second in the Championship table and within touching distance of a place in the top flight – a year after Lambert took them back into the Championship at the first attempt.

'It wasn't just this season, it was last season,' he said. 'They were so unfit. There were so many things wrong, and all credit to the players last season, who did brilliant for us to get us up. And the new lads coming in have been brilliant, allied to the ones that are already here. But somewhere along the line you have got to get about a football pitch. If there is a game where you can play and you can stand about for 90 minutes then I would love to see it, but I'm sorry, you have got to be able to get around.'

Lambert, who took over from Bryan Gunn in August, 2009, said it took him until after the turn of the year to get players up to his standards.

'It takes months,' he said. 'If you look at the injury records what happened last year some lads were getting strains all over the place, but we had to do it to get them up to speed. We got there pretty quickly. It wasn't probably until January, February time that we thought everybody was fit enough.

'I didn't know what it was like before. I knew one thing for sure, that they weren't up to our level.'

Much has been made of Lambert's experience overseas as a player with Borussia Dortmund and in subsequent return visits to Germany as a coach.

'It is a different culture, it is totally different in Germany from Britain,' he said. 'It is nothing to do with running – football-wise it has got to be up there. You trained at a really high intensity – and I played with a really successful side, but we played football. It wasn't running all over the place, we had to play football to an intensity. This is what I do here; we train the way we play and I think the lads enjoy it.

'I think they enjoy the coaching, I think they enjoy coming in to work, which is important, and they have done brilliantly.'

Late winners are clearly no coincidence, no stroke of luck – but Lambert says they don't happen simply because the players are physically fit.

'It's not just a fitness thing, I think it's the mentality of them that they keep going,' he said.

Lambert regularly plays his cards close to his chest over fitness and injury concerns in his squad. Zak Whitbread was replaced with more than a third of Monday's game against Derby remaining with what appeared to be a hip problem, but there was no concrete news on his progress yesterday.

'We will have to wait and see,' said Lambert, who repeated the answer when asked if there were any other injury concerns.