One of the founders of Fitness First is investing in a new chain of American-inspired “high intensity” gym studios using the “pay as you train” business model.

Mike Balfour, the man who helped grow Fitness First into a worldwide franchise, is becoming a non-executive director and investor for One Rebel gyms.

One Rebel hopes to secure £2.7m from investors, to be spent on 10 to 20 gyms and allowing investors to exit after five years.

The “pay as you train” model will be adopted by One Rebel to compete in an industry where low-cost gyms, eschewing joining fees or monthly subscriptions, are becoming the norm.

The first club is expected to open in London this September and will include two or three studios for cycling and treadmill classes, plus either “hot yoga” or a “fight club”.

One Rebel will also draw inspiration from Orangetheory Fitness, brought to Britain by David Lloyd Leisure, which claims customers can burn 500 to 1,000 calories in a 60 minute work-out.

Zillah Byng-Maddick, formerly chief executive of Trader Media Group and finance director of Fitness First, will chair One Rebel.

James Balfour, Mike Balfour's son and former investment banker, will be chief executive and Giles Dean will play the role of operations director.

James previously co-founded the Jatomi Fitness chain with his father and ran its Asian operations.

Chancery Investment Partners are running the investment process.

The initial backers are spending £400,000 on a 60 per cent stake and investors will be able to buy shares through a Chancery investment programme in units of £25,000, which will amount to £2.3m: a 35 per cent stake.

Chancery will have the option of acquiring the remaining five per cent.