AN ODD thing about Ronny Deila is that he wouldn't have been able to get into a Ronny Deila team.

All that running and sprinting and energy? Deila the player - a journeyman defender for Uraedd, Odd Grelnand, Viking Stavanger and Stromsgodset in Norway - knew he wasn't capable of it. If a manager like Deila himself had pushed him hard he'd have been panting and peching like an old horse.

"Throughout the majority of my career I was always strong but I was too heavy," he said at Lennoxtown."I carried too much weight, my body was 92 kilos. I just wish now that someone had said that to me when I was 21. I ate too many carbohydrates, eating all the time. Bodies are different but if I do that I put on weight." His brother-in-law, Siggi Rushfeldt, remains the all-time top scorer in Norwegian football and towards the end of Deila's career he advised him to lose weight. He did and suddenly felt sharper and quicker around the pitch. "I listened to him and got down to 85.7kilos. Think about it, carrying an extra six kilos around. So by the end of my career I was better."

Rushfeldt played 38 times for Norway. Deila was never capped. There was no sense of regret over unfulfilled potential when the Celtic manager talked about this yesterday but it was easy to imagine the episode having a profound effect on his approach to football, just as he entered coaching. It's only six months since Deila was criticised and mocked for questioning the Celtic players' fitness and talking about fizzy drinks and chips. Back then he didn't have the body of results to ensure widespread respect for his methods. That has changed, and according to Deila so has the players' fitness.

The performance analysis figures appear to be startling. "We have increased the high intensity running by 30-40 per cent since the summer," he said. "That is a lot. We want to be direct, we want to create things, we want to have penetration, we want to be a high pressing team, so you have to run and you have to run quick. You see that in the stats and in how we perform." The dynamism of Celtic's second half performance against Aberdeen on Sunday, when they scored three times and overran their strongest domestic challenger soon after a gruelling Thursday night in Milan, illustrated his point as effectively as any fitness data.

Still, the numbers sound impressive. Deila said Inter Milan striker Rodrigo Palacio delivered 1250 metres of high intensity running against Celtic. "That is a number that is incredible," he said, before pausing for effect. "But at the weekend Gary Mackay-Steven ran 1300. The amount of metres and sprints they did in that game was unbelievable when you know that they played three days before."

Stuart Armstrong's 900 metres of high-intensity work was pretty impressive too given that he came on in the 11th minute and went off in the 73rd. He is ready to face St Johnstone at Parkhead tonight but was the fact he went off with cramp against Aberdeen evidence that the players were being pushed too hard? "It was a sign that he is not strong enough yet. You have to think of the mental and physical loading on a player. Just coming to Celtic - dealing with the contract, the media and so on - used a lot of mental energy in Gary and Stuart. And then the training is at a much higher tempo than they have been used to before. That's how you have to manage the squad.

"Scott Brown is doing it every day. He is so strong, unbelievably strong. Why? Because he has done this for many years, he works really hard every single day and he looks after himself. Stefan Johansen is starting to get that into his body. Nir Bitton looked a bit tired against Aberdeen because he has not been used to playing so many games."

The attitude to fitness is not simplistic. Celtic are not doing more training sessions, or longer ones, under Deila than they did under Neil Lennon. It's just that the work and the emphasis is different. "In my experience all the teams that say 'we are going to train double as much as before and we're going to be fit'...they are almost relegated, because you lose focus on the important things. For me, it's what you do in training. We don't train more than they did before but hopefully we train better and we give more in that hour-and-a-half every day."

Other teams can be benchmarks for Deila. He lay on his hotel bed in Milan last Wednesday night and "got very inspired" watching Bayer Leverkusen against Atletico Madrid. "The intensity of Leverkusen was unbelievable. So I try to take something of the sprinting and high intensity they showed and put it into my team. The Leverkusen coach, Roger Schmidt, was previously coach of Red Bull Salzburg who also play with huge intensity. There are things there which are not in our philosophy but we can take something out of it." Could there ever be a place for an old-fashioned, largely immobile ball player in a Deila team? A Matt Le Tissier, for example? "I think if Matt Le Tissier was playing now he would be running. Because he would be asked to do it. Football has changed. He would still be an unbelievable player today but there would be different training."

Emilio Izaguirre and Kris Commons are out tonight but both should be back for the weekend. A Celtic win over seventh-placed St Johnstone will put them nine points clear at the top of the Premiershhip: another act of accelerating away.