"We are not staying open for financial gain but more for our members' mental and physical well-being," says Chris Ellerby-Hemmings, the co-owner of EmpoweredFit gym in the Wirral.
"The reason for doing it is to be listened to."
The gym, which has 14,000 members, is one of dozens in Merseyside that have remained open despite new lockdown rules ordering them to shut.
Some medical experts say gyms could encourage the virus to spread, as they are humid and confined spaces with shared equipment.
But Mr Ellerby-Hemmings told the BBC his gym was Covid secure. "I want to ask the government or local government to show us the evidence as to why we should be closed."
The Liverpool City Region is the only area to be under the toughest Tier Three Covid-19 restrictions which came into effect at midnight, making it illegal for gyms in the area to open.
Any venue mandated to close that remains open faces fines of up to £10,000 for repeated offences, Liverpool City Council said.
Mr Ellerby-Hemmings is acting as spokesperson for the outlets defying the order to close. He says "gyms are not a major spreader of Covid" and there have not been any cases of Covid in the gyms that have remained open, either before or after the previous lockdown.
He also points to research by the gyms' trade body UK Active which found that for 22 million visits across England between 25 July and 13 September only 78 cases have been reported.
Independent gyms like EmpoweredFit are not alone in condemning the closure of fitness facilities in and around Liverpool
National chain PureGym says it is "extremely disappointed" to have to close its seven gyms in the Liverpool area, and is even considering legal action to reverse the rules.
It says since reopening after the previous lockdown there had been more than 300,000 visits to these gyms by about 31.000 members and they had only been notified about 11 members and staff who tested positive for Covid-19,
It is calling on the mayors and leaders in the region and national government to "seriously reconsider their decision".
"If they fail to do so they will have to face and live with the consequences of a less healthy population and associated poorer health outcomes including a weaker immune system," PureGym's boss Humphrey Cobbold said in a statement.
"We will consider any and every course of action that can be taken to support our industry and members including recourse to legal processes if that is what it takes," he added.
'The evidence stacks up'
Huw Edwards is chief executive of UK Active which is calling for the decision to close gyms in Liverpool to be reversed.
He told the BBC the organisation fully supported the "direction of travel PureGym and other operators are looking at".
He too said the decision to close gyms should be based on evidence.
"All the evidence stacks up that the sector is safe."
He said there had been 0.34 cases of Covid per 100,000 visits to gyms and leisure centres in the UK. "There isn't a safer sector in the UK right now, so the government's decision is not based on the evidence," he said.
"The reality is the closure of gyms and leisure centres in Liverpool will lead to significant business failure, will lead to job losses and according to a Sage [Scientific Advisory Group on Emergencies] report released on Monday will have an adverse impact on the health and wellbeing of people in Liverpool."
EmpoweredFit's Chris Ellerby-Hemmings said his gym "could have gone out of business" as a result of the first lockdown.
In July, he and co-owner Thea Holden thanked their members who had "continued to pay and support us throughout lockdown", saying they had been a "big hand in ensuring that we can reopen".
He said they were now being told to close again "with minimum financial support for six months", but stressed that his decision to stay open was not for "financial gain".
"We're not doing this in an irresponsible manner, we're following all Covid guidelines as we have been all along and the reason we're doing this... is to prove that gyms are a safe place to come and they're a safe place to train."
Despite the Department for Culture, Media and Sport saying it was a local decision in Liverpool to order gyms to close, in a tweet on Tuesday Mayor of Liverpool Joe Anderson suggested local authorities had no choice.
He tweeted: "Me on Saturday to No 10 officials 'Gyms are safer than supermarkets, more COVID-19 transmissions come from our schools and retail than Gyms' response 'we are not closing schools or restricting retail, so we can only go for Hospitality & leisure.' Government decision not ours!"
Claire Hamilton, political reporter, BBC Radio Merseyside
Like hospitality venues, some gyms are dubious about the evidence for their premises being a major source of transmission for the virus.
The row over their inclusion in the shutdown has prompted questions over whether it was local leaders or the government who decided they should close.
Gyms aren't on the baseline list of businesses which should automatically shut in Tier 3 restrictions.
But local political leaders insist they didn't add them, and are lobbying government to keep them open.