Discount gym chain Planet Fitness (PLNT) shares didn’t run out of the gate on its first day of trading, but there are plenty of reasons to be pumped up over the gym chain’s prospects. Planet Fitness Inc. priced its initial public offering at $16.00 a share. The deal raised about $216 million by selling 13.5 million shares. ‘It’s the atmosphere first, and then the price, it’s not the meat market environment thing found at most gyms,’ said Planet Fitness CEO Chris Rondeau in an interview with TheStreet about why the chain has become popular with consumers. As of March 31, 2015, Planet Fitness boasted 7.1 million members, up 24% year over year according to its prospectus filed in June. Since the start of the year, the company has added 1 million members. Planet Fitness has posted an unworldly 33 straight quarters of same-store sales growth. The outlook for growth looks equally strong. As of March 31, 2015, Planet Fitness franchisees have signed agreements to open more than 1,000 additional stores over the next seven years, including roughly 500 over the next three years. Rondeau says the U.S. has the potential for over 4,000 locations – currently there are over 900 sites.