NEW YORK (TheStreet) -- Planet Fitness (PLNT) - Get Report  shares are spiking 2.31% to $15.98 on Wednesday morning, extending gains from yesterday when the fitness chain reported strong first quarter 2016 results after the market close, sending shares up in after-hours trading. 

Adjusted earnings of 15 cents a share topped Wall Street's expectations by 2 cents and was up from 13 cents a share it earned the previous year. 

Revenue rose 8.3% to $83.3 million, also beating forecasts of $77.9 million.

"The year is off to a strong start," ECO Christopher Rondeau said. "We continue to be successful attracting new consumers to Planet Fitness, which, combined with system-wide same store sales growth of 6.8% contributed to our outperformance in the first quarter compared with guidance."

Thanks to the growing customer base, the company said it expects full-year 2016 earnings to be between the range of 62 cents to 65 cents a share and revenue to be between $360 million to $370 million.

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