Not only can your muscles get bigger, but perhaps your portfolio as well.

The company that calls Newington it's home (for now), Monday announced 13,500,000 shares of its Class A common stock.

Planet Fitness says underwriters will have a 30-day option to buy up to an additional 2,025,000 shares. The IPO has an estimated price range of between $14 and $16 per share.

I've been a member of Planet Fitness on and off for a number of years, but I've always enjoyed their staff and like spending time there. It's 'Judgement Free Zone' mantra does seem to set it apart from other gyms.