The owner of the 25-gym Boston Sports Clubs chain, Town Sports International Holdings Inc., will pay a one-time dividend of $3 per share as the company seeks to boost shareholder returns, Dow Jones reported. The New York City company, which has a total of 160 fitness clubs in New York, Washington, Philadelphia, and Switzerland, as well as Boston, expects the special payout to cost $71.4 million. Town Sports will borrow an additional $60 million under its senior secured credit facility to help fund it.