The science behind Leicester City's Premier League promotion

Refinement over reinvention - that has been Nigel Pearson's approach to ending Leicester City's 10-year Premier League absence.

In a moment of heartache at Vicarage Road, where their hopes of winning promotion were dramatically ended by Watford last term, the Foxes' path had already well and truly been set.

Eleven players who lined up against the Hornets last May were on hand to help finish the job 10 months later as Leicester beat Sheffield Wednesday - a victory that ultimately proved enough to secure their top-flight status with six matches remaining.

Pearson and his team gave BBC Late Kick Off Midlands an all-access pass for an exclusive insight into the side's evolution from the nearly-men of 2013, to head of the class in 2014.

"If everyone improves by a couple of percent, it very quickly adds ups. That is really what it's about," said Pearson.

In a term made famous by Great Britain's incredibly successful Olympic track cycling team at London 2012, 'marginal gains' has become the mantra adopted at City's Belvoir Drive training ground.

The results are the riches of the Premier League and a 21-game unbeaten run that has taken them there.

But it all starts with the team behind the team - from Pearson's management staff, scouts, match analysts, sports scientists, strength and conditioning coaches, physiotherapists and nutritionist.

"We are all trying to work towards the same thing," said Pearson.

"The margins of error are very, very small and it's becoming even more of a fine line between success and failure.

"We have experienced the highs and lows in the last 13 months - it is difficult to quantify the work you do, but ultimately we are trying to improve on every level we can.

"I am fortunate and very privileged to work with a lot of people who are experts in their own field, and their attention to details in contributing to results is valued by myself and the players."

For all the tactics mapped out in Pearson's office, weights lifted in the gym, drills run on training ground and match footage edited this season, the whole plan was masterminded in a Shropshire pub last May.

City's head physiotherapist Dave Rennie, who has been with the club for 15 years and worked under 20 different managers, said a pint of beer seemed like the logical place to start after getting to within two wins of promotion.

"We are British and went to the pub, so we had two days at Nigel's father in-laws pub in Shropshire which was fabulous from what I can remember," said Rennie.

"It proved a non-threatening environment for us to talk as a group of people. It was at that point that we went away as staff and de-briefed the positives from the season and discussed where we really needed to go in terms of changing the philosophy a little bit more.

"We were almost at a level where we thought things were right, but there were little areas we thought we could improve."

With match analysis software uploaded to tablet computers, development has been hardwired into the Foxes.

No moment or yard is unaccounted with players plugged in the instant they arrive at Belvoir Drive, as every player studies their previous performance before being hooked up to a GPS system and heart monitor.

"I'm preparing for training whilst watching my game at the weekend, so it gives me the opportunity to watch while I keep working," midfielder Matty James said.

"Attention to detail has played a key part throughout this season."

In a season where Leicester saw no reason to fix what was not broken, shrewd transfer dealing has still proven crucial.

Assistant manager and head of recruitment Steve Walsh - who had an 18-year association with Chelsea as a scout and worked with Jose Mourinho before leaving in 2006 - saw reason to sign 33-year-old Poland international Marcin Wasilewski, despite the player having suffered a horrendous broken leg while playing in Belgium in 2009.

"He had a difficult time, had that double leg break, but we did some research on how he had got back," said Walsh.

"We asked him if he could come in so we could have a look at him on trial.

"This is a player with 60 caps for Poland and once we brought him in we could see that. He fit the bill and has been an excellent purchase."

A lot can be said for the amount of faith invested at Leicester City this season, with Pearson the longest serving manager on duty in the Championship.

Rennie had already seen Pearson come and go, guiding City to promotion from League One in 2008-09 then to the Championship play-offs the following campaign in a successful first spell.

Two managerial appointments later, including the big-spending reign of Sven-Goran Eriksson, and Pearson was back at the King Power Stadium.

"We have seen lots of different management styles, we have to roll with a few and duck a few others," said Rennie.

"That is football and can be very unsettling - Nigel has provided us with a good period of stability.

"He is very very innovative, what he is clever at doing is utilising the other member of staff. He gets us behind him then drives us forward."