It’s the start of a class known as high-intensity interval training, a combination of treadmill and weight-lifting, at the boutique fitness studio Barry’s. The brothers and Rondeau, who now serves as Planet Fitness’ chief executive, hit upon a concept. Planet Fitness’ tag, “judgement free zone” is true to form. Part of the appeal is its $10 a month basic membership fee – which hasn’t changed – that Planet Fitness primarily collects through electronic funds transfers. Still, with solid and regular profits and a reasonable amount of debt, Planet Fitness has staying power, even if shareholders lose their shirts while its valuation comes in line.

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