One of the women who commented on Tisdell's video was a staff member at the gym chain.
The staff member posted a number of laughing emojis on Tisdell's post and wrote "aw when you know who the member is".
The GO spokeswoman said the staffer "deeply regrets her social media comment and is in the process of issuing an apology to the member in the video".
The club said the employee's actions were in breach of its code of conduct and "appropriate action has been taken to deal with the matter".
The gym said it was committed to helping the woman in the video and pledged to "support her moving forward".
Tisdell has gone to ground since the Daily Mail revealed his post, shutting down his social media from the public.
He regularly posted pictures of himself flexing in the gym.
His video was branded 'disgusting' by an outraged gym-goer who contacted the Daily Mail.
Since the story was published hundreds of angry members of the public took to social media to call for action.
It comes at a time of year where many gyms are actively soliciting new members keen for a "new year, new you".
One customer, who asked not to be named, slammed Tisdell's behaviour as "disgusting".
"He's starting an ongoing trend to publicly shame and embarass people," the customer said.
"The most disgusting part is this gym is in a very low socio-economic part of Brisbane.
"He should have gone up to her and asked if she wanted him to show her how to use the equipment. It's online bullying".
She said the "online shaming" is going to start to affect the culture around gyms in the area and will mess with people with low confidence.
"I can handle it, but when I saw what he did to this elderly woman, I was shocked," she said.
It comes after Playboy model Dani Mathers - who has admitted to taking a photo of a naked, 70-year-old woman in a gym locker room and posting it on Snapchat - pleaded not guilty Monday to invasion of privacy.
Mathers, 29, was not in court when her attorney entered the plea to the misdemeanor count on her behalf, City News Service reported via NBC Los Angeles. She was not required to attend.
Outside the courtroom, defense attorney Tom Mesereau said Mathers 'very much regrets' what happened.