Football managers have used their fair share of inspirational pre-match speeches over the years, but how many of them have been delivered nude?

It has been, ahem, revealed, that that was the shock tactic delivered by Ronny Deila - the man in charge of top-tier Norway club side Valarenga - during a bad form slump for his side last month.

With his team in a battle against relegation, the former Celtic manager went to desperate measures to inspire the troops, with the 42-year-old stripping bare to address the team ahead of their home clash against Brann three weeks back.

"A lot of people have probably seen me nude already," Deila said in reflecting on the move. "We have to have fun in all the seriousness."

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And, you know what, the risky, or should that be risque, manoeuvre, paid dividends, with Valerenga - who hadn't tasted victory in seven outings - winning the match 2-1, then backing that up with another win at home, to lift the Oslo-based club out of the relegation places, with six games remaining.

Deila has history in the removing of clothes department, in 2009 having celebrated avoiding relegation when managing Stromsgodset, by jumping around in his underwear.

However, he says he will not be making the naked speeches a regular thing, and that it was just done for the "surprise effect".

That should please the playing group.

"No one was really disappointed that he has not done it again since," said captain Christian Grindheim, who did acknowledge, though, that the players got the message.

"It was perfectly fine. It was a metaphor to try and be ourselves. He wanted us to relax our shoulders."