The company, which operates 190 discount gyms across the UK, saw revenues tumble by more than a fifth for the past six months.
The Gym Group has hailed a “rapid recovery” in membership numbers after reopening sites following enforced closures earlier this year.
It came as the company, which operates 190 discount gyms across the UK, posted a £19.4 million operating loss for the half-year to June.
The firm saw its losses grow marginally after revenues slumped by 21.4% to £29.3 million, compared with the same six-month period last year.
The Gym Group said it was closed for more than half of its trading days for the half-year but said it is now looking forward to a “period of sustained recovery and accelerated growth” after reporting strong demand for membership after reopening sites in April and easing restrictions further in July.
At the end of June, the company had 730,000 members, rising around a third from its low of 547,000 members at the end of February.
In July, the firm raised £31 million from investors to help drive its post-pandemic growth plans, with the firm seeking to open 40 more gyms by the end of 2022.
Richard Darwin, chief executive of The Gym Group, said: “Since the reopening of gyms in April, The Gym Group has performed strongly with excellent member feedback, a higher rate of visits per member and a rapid recovery in overall membership levels.
“We have identified some exciting growth opportunities to expand our estate further and raised additional funds from shareholders to capitalise upon them.
“With restrictions now lifted, we are planning to open 40 new sites by the end of 2022, of which three have opened so far in July and August, as we continue to make fitness accessible for all and deliver further social value to communities around the country.
“We look forward to the second half of the year and beyond with confidence.”
Shares in the company were 1.6% higher at 287.5p in early trading.