Sheffield gym users have expressed their shock over the death of an 'energetic and enthusiastic' personal trainer.
Charlie Quinn, aged in his 60s, was a popular member of the fitness team at Ponds Forge International Sports Centre and was well-known to thousands of gym members.
A statement on the centre's Facebook page said this morning: "It is with great sadness we inform you of the loss of Charlie Quinn our personal trainer from our fitness team at Ponds Forge, who sadly passed away over the weekend.
"We have placed a book of condolences in the Ponds Forge gym to be signed.
"Our thoughts are with Charlie’s friends and family at this sad time."
The circumstances of his death have not been revealed but tributes have flooded in from friends and fellow gym users who expressed their shock and sadness.
Josh Coburn said: "So incredibly shocked and deeply saddened to hear that the man, the myth the legend, Mr Charlie Quinn has passed away.
"I'm struggling to even comprehend it. He was the happiest, most energetic and enthusiastic man I have ever met. An absolute bundle of energy and joy."
He added: "Laughter would never be more than a few seconds away in his company. I cannot quite believe he has gone. Saying he will be sorely missed would be an understatement."
Jamie Baz added: "The greatest respect for that man."
Becky Foster posted: "I'm absolutely shocked by this news. I can't believe it, I trained with Charlie 12 days ago.
"He's a fantastic man and was loved by everyone at Ponds Forge.
"He always put so much effort and hard work into every training session."
Charlie was born in Gibraltar and joined the Royal Air Force after leaving school at age 17. He served for 22 years as a physical training instructor, working all over the world including the UK, Germany and Belize.
He lived in Harthill and it is believed he had three children.
Charlie did an interview with the Star and Telegraph in January 2016 in which he told us about his five favourite things, which he listed as Harthill, Thorpe Salvin, Millhouses Park, Ponds Forge and Sheffield High Street.
He spoke fondly about his place of work, saying it was a "privilege to be based in the same place that countless Olympic athletes train."