"I think ex-military sometimes get a bit of a bad reputation,” says David Waldie, a smile almost reaching the face of Carlisle United’s strength and conditioning coach as he explains the principles he brings from his time in the Royal Air Force to Brunton Park.

Waldie has a crucial role at United at the start of a pre-season that manager Steven Pressley wants to use to prepare his squad for the “high-energy” football he intends to play in 2019/20.

Waldie joined the club midway through last season and, while he has a football background with clubs like Lincoln and Notts County, 10 years as a physical training instructor with the RAF also shaped him.

He says the “bad reputation” forces men get is sometimes down to being “extremely regimented and organised”. But he adds: “Yes, you have to be flexible, but being organised and flexible are key in a fluid football environment, where things can change at the drop of a hat.

“I like to think I’m quite organised, and have a plan, but it comes down to getting the players to buy into a plan. You can have the best plan in the world but if they don’t believe you, think you’re genuine or actually care about them, they’re not likely to execute the plan.”

Waldie, who left the RAF in 2015 in order to pursue a career in the game, comes across as a man keen to practice what he preaches. When not staying in Carlisle, the 36-year-old says, his alarm goes off at 4am twice a week so he can drive from his Lincoln home and train in United’s gym before the other coaches and players arrive. “It sets me up for the day nicely,” he says.

For those players, who reported back yesterday, these are the early and invariably hard days of summer. The work will not be as basic as “running like a horse,” in the words of new signing Byron Webster; modern pre-season training is more nuanced and tailored. Certain principles are, though, the same, says Waldie, who relishes his position.

“It doesn’t feel like a job, to be honest,” he says. “I’ve done it for years and I’m passionate about it. I don’t want to be stuck behind a desk at a computer. I like being in the gym, out on the football field, improving players and athletes – and in the past, soldiers – just pushing them.

“A lot of people don’t know their limits. It’s getting them to a point where they realise they can work a little bit harder than they thought they could, so that when it comes to tough games, digging in, maybe extra-time in cup games, they’ve been to that place and they know what it feels like.”

Waldie is the latest professional hired by United to work on these areas. Their first specific fitness coach, Lee Fearn, was brought in by Graham Kavanagh in 2014. He left last summer and Paddy Maher stepped up from the academy. He also moved on last season and while Waldie worked with Pressley’s team from February, this is his first summer.

It has already seen him give players detailed close-season fitness plans. “I’ve been keeping tabs with them through the off-season,” says Waldie. “We’ve tried to find a balance between [that and] letting them have some free time away from being told what to do for a couple of weeks, relaxing with their families. But hopefully they come back in a state ready for pre-season. They’ve been told how tough it’s gonna be. If they come back in poor shape, it’s going to be an uphill struggle.”

Waldie says he is pleased that United, under Pressley, are trying to recruit players who match his own attitude to fitness. “It’s just so important – you can’t carry out the tactical work or the style of play the manager wants if the lads aren’t fit and able enough to do that task,” he says. “I think we struggled with that at stages last season.”

Waldie, who says pre-season will be built around 11v11 work of increasing volume, insists there was only so much he was able to impose last term. “It’s so hard to try and improve fitness during the season, when games come thick and fast. What I tried to do is work on areas away from [the club]. I worked on diet and nutrition with the lads, tried to educate them on recovery strategies, rather than just bring them in and make them do more running, because sometimes more isn’t the answer. Some lads bought into it, some not so much.”

Many years before moving into football, Waldie joined the RAF as a physical training instructor, later specialising in exercise rehabilitation, whether with straightforward injuries or with battle victims. “A full spectrum of different injuries, different personalities, lots of psycho-social issues as well to take note of,” he says.

Working with soldiers suffering the physical scars of conflict required a particularly open-minded approach. “You could go into a session and have the plan laid out, but then they might say something that hits home with you and you have to change the whole session,” he says.

“You might end up chatting about something totally different, about sleep, or recovery, or nutrition – or nothing, because you don’t feel that actually doing that session is worthwhile and you’re better spending it in a different area. It’s about having that flexibility to go in different directions with experiences you think will benefit that person.”

Waldie says the mechanics of his job received a thorough grounding in the RAF. “The lad that joined up in 2006 is totally different to the lad sat here now,” he says. “The school of PT at RAF Cosford, where I spent nine months learning to be a physical training instructor, put me in such good stead.

“I’m talking about [things like] the small detail of how to take a warm-up. We did that for weeks on end: where to stand, voice projection, body position. A lot of people, sports scientists, strength and conditioning coaches, come straight out of university, and they don’t have access to nine months of intense training like that, where you’re getting critiqued every day.”

Waldie admits that, as he rose in the military, he found himself behind a desk “doing admin” and recognised his passion lay elsewhere. He says he spent “hundreds, thousands of pounds on petrol and diesel” commuting to clubs as he sought a foothold in football, working with Sheffield United’s academy as well as Notts County and Lincoln, before arriving full-time at Carlisle, a club he likes because it has a “small, close-knit staff”, which includes the long-serving physio Neil Dalton.

This period of pre-season, he says, will involve getting to know United’s players as well as possible, working out their strengths and establishing their approach to, and technique in, the gym. “I’ve had a lot of players in the past say, ‘I don’t do weight training, I’ve never done it and I’ve done alright’,” he adds. “Sometimes I need to flip their beliefs, or show it’s going to benefit them.”

Waldie says he has a strong rapport with Pressley and is “positive” about the path United are on, along with his part in it, the new season just over a month away. “I like to think I’m quite approachable, and I’ll be totally honest with the players,” he says.

“Some will be subjective views, some will be objective. I like numbers to highlight areas they need to improve. It’s about wanting the best for them and understanding where they’re coming from. I like to try and get to know them a little bit, but we have to do it pretty quickly.”