Any suspicions that the boutique studio boom is stealing the thunder of fast-growing budget gyms has been dispelled by the latest Sunday Times Virgin Fast Track 100 list, which names Pure Gym and Xercise4Less among the 20 fastest growing private firms in the UK.

Having dominated last year’s list alongside The Gym Group, both Pure Gym and Xercise4Less made improvements on their rankings in the list of the 100 UK private companies with the fastest-growing sales over their latest three years. Pure Gym climbed 9 places to rank 9th, while Xercise4Less edged up four places to 17th. The Gym Group is no longer eligible, having gone public at the beginning of last month.

The league table – due to be published in The Sunday Times on 6 December, but seen in advance by Health Club Management – shows that Pure Gym sales for 2014 reached £68.6m, reflecting annual sales growth over the last three years of 121 per cent. 2015 has also been a busy year for the UK’s largest gym chain, with new CEO Humphrey Cobbold taking the reins, followed by the high profile acquisition of LA fitness. Pure Gym is currently working to convert these new sites, with the project expected to be completed by May 2016.

Meanwhile Xercise4Less, which plans to hit 100 sites in 2017, had annual sales of £21.8m to July 2015, with three-year annual sales growth of 99 per cent.

“Our organic business model is tried and tested to ensure we can adapt and flex to stay ahead of the game," Xercise4Less CEO Jon Wright told Health Club Management.

"We’re a very ambitious brand and our rapid expansion has outperformed our biggest competitors. We are in a healthy position ahead of 2016 and very much looking forward to an even bigger roll out in the New Year.”

The strong showing from low cost gyms comes just weeks after fitness industry analyst Gareth Jones suggested the private fitness sector could now be worth ‘north of £15bn’, with budget chains cited as a huge driver of growth.

Pure and Xercise4Less certainly stacked up well against the wider market. This year’s Fast Track 100 companies achieved, on average, sales growth of 65 per cent a year over three years, from a total of £816m in 2011/12 to £3.7bn in 2014/15. They more than tripled their combined workforce to 19,500 people over three years, having added 13,500 jobs over the period, some as a result of acquisitions.

“This year’s Fast Track 100 is packed full of entrepreneurs and family businesses tackling many different challenges head-on and thriving thanks to their team spirit and togetherness,” said Virgin founder Sir Richard Branson.

“Entrepreneurship and family values are at the heart of everything we do at Virgin. Like many on the Fast Track 100, we’ve turned a family business into a business family. Working with family works."