|Scottish Cup replay: Celtic v Dundee United|
|Date: Wednesday, 18 March Venue: Celtic Park, Glasgow Kick-off: 19:45 GMT|
|Coverage: Listen on BBC Radio Scotland 810MW/DAB/online; updates on BBC Sport website|
Manager Ronny Deila feels Celtic are "much lighter" as they seek continued domestic success.
The Premiership leaders picked up the first trophy of Deila's reign by beating Dundee United in Sunday's Scottish League Cup final.
They face United again in Wednesday's Scottish Cup quarter-final replay.
"As a team we have dropped 50 kilos in six months," said Deila. "That's a lot. Things are getting quicker and sharper in training."
And he added: "It's all about tempo. It's not only a physical thing, it's also a tactical thing that you have to work in the intensity you want to play, maybe higher."
The Norwegian experienced a difficult start to his time in Glasgow, with Celtic knocked out of the Champions League and stuttering at the outset of their Premiership title defence.
However, Celtic gradually worked their way to the top of the league and reached the last 32 of the Europa League, being knocked out by Inter Milan.
And Deila's men remain in contention for a domestic treble. The winner of Wednesday's meeting with Dundee United at Celtic Park will face Inverness Caledonian Thistle in the Scottish Cup semi-final.
"I think we have progressed a lot in the things I want to bring into the culture and how we want to work," added Deila.
"I'm starting to really enjoy it. In the beginning it's enough to be there, you don't know where to start. Now it's settled, everybody knows their role and what's expected, and now we have to work better than we have done before.
"There is so much to go but that will never stop. But we have done a good job so far and we just have to keep working in the same way, and I think we will get even better results.
"When you are at a club like Celtic, the pressure is so unbelievably high so everybody in the club is always thinking about results. And that's the wrong way of thinking in my opinion, but it's very hard not to do it.
"So everything has been an environment that's all about results, then you don't get any creativity because you are so afraid to do something different.
"To get that culture of development, to get people to get into what to do every day and try to improve things, that has been the biggest challenge for me.
"People understand that we want to get the best out of them and the players are getting very interested in doing the things to improve themselves."