Cardiff and Swansea prepare to tackle the emptiness of the post-lockdown player

As the Championship resumes, a window of opportunity is open for Cardiff City and Swansea City.

But only if they can deal with being behind closed doors.

The action will return this weekend but the fans will not, meaning the Welsh rivals' play-off hopes will be played out in front of empty stands in echoing stadia.

In theory, it should make little difference to any of the sides still hoping of making the top six after these final nine games.

The reality, though, could be very different and could yet play a decisive factor in the scramble for the final promotion spots.

"It will be very different and any manager that says it'll just be the same is not telling you the truth," says former Wales midfielder Carl Robinson, manager of A-League side Newcastle Jets who played two games behind closed doors in March before Australian sport was shut down.

"It's something everyone has to deal with but it's not easy."

'Strange' has been a word that has cropped up from many in anticipation of the often frenetic Championship returning without its supporters.

Wales and Schalke winger Rabbi Matondo described his experience behind closed doors in Germany's Bundesliga as "weird".

But it goes beyond simply a sense of the unusual.

"It's going to be problematic," says Brendan Cropley, a professor of sports coaching at the University of South Wales who specialises in mental performance.

"Essentially a manager and his backroom staff spend their week trying to prepare players for what they're going to face on a match day, whether that's physical demands, technical and tactical demands, and also mental demands - and that includes managing the crowd and atmosphere.

"They would want to try and normalise the situation so players will feel comfortable in it and be able to express themselves and execute game plans.

"As soon as you change the situation, some of those worries will re-emerge, the worries of what it's going to be like.

"Irrespective of how much training they've done behind closed doors, it will feel like a very abnormal situation and it will take a range of different processes and activities to prepare the players for this different environment."

Two and three points outside the play-offs respectively, Cardiff and Swansea warmed up for the restart by holding a derby of a different kind; two 80 minute matches behind closed doors at Cardiff City Stadium.

It will be where the Bluebirds welcome leaders Leeds United on Sunday, a fixture that has long had an edge to it and would normally see the hosts hoping for a hostile atmosphere to intimidate opponents and inspire themselves.

It is a trait that helped them to promotion in the past, yet such home comforts are not on offer.

Furthermore, the Bundesliga's return has suggested home advantage no longer exists in the new normal, with the number of away wins increasing 13% to 48% since football came out of lockdown. The Championship so far sees a 30% away win record compared to 43% at home.

"Fans create an atmosphere that can help support players in terms of noise, but they can also affect the momentum of games, the way in which the crowd are able to help increase or manage arousal levels," says Cropley, who also works with the Football Association of Wales Trust.

"But also they can be a distraction, they can make players really worry about making mistakes, about trying to live up to the expectations of the fans or manage what the fans are shouting onto the pitch.

"Fans will always have either a positive or a negative effect on individual players on teams and taking that away, we won't know how teams will react."

Matondo offered an insight when he said that he had to lift himself for games, finding motivation from within that fans normally provide.

Yet there is a school of thought among some observers that Swansea - a side that performed better away from home for long spells this season - could benefit with the home pressures taken away from their young, technical players.

"You kind of get that feeling of when you were a young lad," says Swansea goalkeeper Freddie Woodman of his research watching behind-closed-doors games so far.

"You can hear every shout on the pitch and the ball pinging about.

"It will be different but once the games start, there's so much up for grabs that I think you will see the competitive edge."

There is the possibility some clubs could pipe in fan noise - something Swansea head coach Steve Cooper says his side have prepared for in training ahead of Saturday's trip to Middlesbrough.

Robinson, a Championship promotion-winner with Portsmouth and Sunderland, does expect significant changes to the usual fast-paced fare.

"I think you will see a drop in the intensity of the football, " he says. "You won't get that euphoria the crowd brings you which can enable you to increase workloads maybe five or 10%.

"I think you'll see a slower, more tactical game and, as a manager, to watch that side of it is really fascinating because that's where you actually find out how good managers are.

"Sometimes emotion and momentum can take you through a game but you get caught up in it and end up thinking about the result rather than what's happening in the game.

"So now I think you're going to see the good tacticians coming through over this period of time."

It means, as a clutch of clubs - including two Welsh rivals - jostle for those top-six places, empty stadia could be a lonely place for managers.

Starting this weekend, we will all see what is going to happen behind those closed doors.