Founded in 1973 and based in New York City, as of 2007 TSI Holdings operated over 155 clubs with approximately 483,000 members.

New York City is home to the majority of the clubs under the banner of NYSC or New York Sports Clubs. There are over 120 NYSC clubs in New York, New Jersey and Connecticut. Boston is home to the second largest majority of clubs under the banner of BSC or Boston Sports Clubs with over 25 locations in Metro Boston and Rhode Island. PSC, Philadelphia Sports clubs has over 8 locations in Philadelphia and New Jersey, WSC, Washington Sports Clubs, has over 17 locations in D.C., Maryland and Virginia.

Corporate Regional offices are located in Boston and Philadelphia.

TSI, the parent company has it Corporate offices in New York City.

NYSC was often the club that the ladies on "Sex and the City" worked out at.

BSC is the official club of both the Boston Red Sox and the Boston Celtics, as of 2006.

The NYSC clubs include a set of eight machines on the fitness floor for use in a program called XpressLine. The program is meant to provide strength training for all muscle groups in a 22-minute workout.

The program includes the following machines: