An instructor was showing people how to prepare their muscles for a stretching routine.
Facebook banned an online video fitness class for pensioners after it mistook leg oiling as sexual content.
John Molyneux, who runs the MolyFit training programme for dozens of over-65s around St Albans, Hertfordshire, said he was shocked to be told by the social network that the post “went against community standards on nudity and sexual activity”.
The fitness instructor was showing people how to oil leg muscles ahead of a stretching routine, raising his shorts up slightly to demonstrate the massage technique.
But shortly after the live stream ended it was taken down.
Mr Molyneux said of Facebook’s claims about his content: “Nothing could be further from the truth.
“I really couldn’t believe it.
“My clients like to see exactly how to do things and all I did was roll up my trouser leg. And amazingly Facebook closed me down.”
Like many sport and fitness professionals, Mr Molyneux has adapted his classes into online Facebook Live sessions as he can no longer visit clients in care homes during the coronavirus lockdown.
He said Facebook later acknowledged the mistake and reinstated the video.
It is not clear how the error occurred, though Facebook relies on artificial intelligence to detect and remove some of its content.
A Facebook spokesman said: “This content was removed in error and has now been restored.
“We hope people can get back to enjoying keeping fit.”