Gyms/Exercise Clubs

24-hr. Fitness

100 California (at Davis), 434-5080

303 Second St. (at Folsom), 543-7808

350 Bay (at Powell), 395-9595

1850 Ocean (at Ashton), 334-1400

1645 Bryant (at 16th St.), 437-4188

1200 Van Ness (at Post), 776-2200

3741 Buchanan (at Bay), 563-3535

2145 Market (at Church), 864-0822

www.24hourfitness.com

This basic fitness chain provides an affordable alternative to fancier and more conceptual city gyms and exercise clubs, and most locations offer a respectable range of classes and facilities. But check before you head out because, despite the name, not each location is open 24/7.

Bay Club

150 Greenwich (at Sansome), 433-2200, www.sfbayclub.com

555 California (at Kearny), 362-7800, www.bayclubbofa.com

If you're fickle about your sporting choices, the Bay Club has plenty of options to flit among, with an aquatic center and facilities for Pilates, circuit training, basketball, squash, and tennis. Bay Clubs also offer useful amenities that are uncommon elsewhere: childcare, laundry service, and Financial District shuttle.

Bodytonic

1300 Sutter (at Van Ness), 440-1800, www.bodytonicSF.com

Workouts and classes for both body and soul are available at this beautiful facility, which boasts 20,000 square feet of floor space for circuit training; exercise classes such as kickboxing, step, and cycling; and mind/body classes such as Pilates, yoga, tai chi, and Feldenkrais.

Bootcamp San Francisco

1052 Jackson (mailing address), 921-8537, www.bootcampsf.com

These six-week courses (four days a week for six weeks) take "privates" outside for intensive cross-training sessions geared toward toning -- double-quick -- whether one is beginning to get in shape or needs to blast past the present plateau.

Cathedral Hill Plaza Athletic Club

1333 Gough (at Geary), 346-3868, www.chpacinc.com

Swimming and tennis feature alongside classes in Feldenkrais, Pilates, Iyengar yoga, sculpting, and various forms of aquatic fitness and cross training in this luxurious (but not greedily so) club. Free pass available on the Web site.

Club One

1 Sansome (at Sutter), 399-1010

450 Golden Gate (at Larkin), 876-1010

Embarcadero Center 2 (at Davis), 788-1010

1755 O'Farrell (at Fillmore), 749-1010

950 California (at Mason), 834-1010

535 Mason (at Post), 337-1010

350 Third St. (at Folsom), 512-1010

www.clubone.com

Whether you are getting into racquet sports, aquatics, or volleyball, toning up solo through circuit training, or joining a like-minded group in a mind/body class, Club One has elaborate options that vary from location to location. Schedule a free visit through the Web site.

Cole Valley Fitness

957 Cole (at Parnassus), 665-3330

This facility serves a stylish, hilly, and gastronomically tempting neighborhood with straight-ahead, non-gimmick equipment and space for serious cardiovascular and weight training (i.e., no dance or other sorts of classes).

Crunch

1000 Van Ness (at O'Farrell)

61 New Montgomery (at Mission)

888-2-CRUNCH, www.crunch.com

This national chain with a Hollywood reputation is one of the more fun clubs around, with fairly new, Internet-savvy equipment, creative classes (cardio striptease, anyone?), and friendly workouts for all levels.

Curves

638 Stanyan (at Page), 221-6932

1874 Market (at Laguna), 431-4693

2300 Clement (at 24th Ave.), 387-9000

555 Buckingham Way (at Stonestown Shopping Center), 681-2145

2529 Van Ness (at Union), 771-0445

608 Portola (at Woodside), 759-9103, www.curvesinternational.com

This national franchise of fitness centers for women of all sizes and abilities has grown in popularity in recent years due to its demanding 30-minute workout system, which includes exercises on water-based hydraulic machines that provide double-positive push and pull resistance for rewarding results with less overall time.

Gold's

1001 Brannan (at Division), 552-4653

2301 Market (at Noe), 626-4488

www.goldsgym.com

The muscle gym originally birthed almost 40 years ago in California's Venice, Gold's is now the largest franchised gym in the world (three-million-plus members) and keeps up-to-date with tech-savvy offerings such as online workout planning and modern weights and equipment. Gold's seems to have lost a bit of its intimidating, iron-pumping bulldog image a bit over the years, too (which is a positive, in our opinion).

Golden Gate Fitness

1248 Ninth Ave. (at Irving), 682-8911, www.goldengatefitness.com

More than 60 classes a week (with consumer-friendly names like "Love Your Ass" and "Kick Some Booty") and a complete gym area keep this Sunset facility active with members of all ability levels. This club has also just introduced a health science program to help integrate diet and nutrition with physical regimens.

Gorilla Sports

2830 Polk (at Union), 292-5444

2324 Chestnut (at Scott), 292-8470

2450 Sutter (at Divisadero), 474-2699, www.gorillasports.com

Dave Fox's nine-year-old Gorilla Sports (which offers a free guest pass online) pioneered the Kwando workout, a hybrid of tae kwon do and aerobics. Gorilla is noted as a strong center for classes and instruction in boxing and kickboxing, but it also has such mind/body staples as Pilates and Yoga. The Polk Street location, in the renovated Alhambra Theatre, screens films while you work out.

Pacific Heights Health Cub

2356 Pine (at Fillmore), 563-6694, www.ph2c.com

PH2C keeps a limited membership (and relatively limited hours) to prevent the overcrowding all too common at fitness centers below the Heights. A complete renovation two years ago has the place looking very fresh. Health screening and physiological testing help set members up for top-notch personal strength and toning training.

Peak Performance

315 Sutter, 3rd Floor

392-9662

Owner Jennifer Stacey founded the first classical Pilates centers in the Bay Area in 1989. An exercise physiologist, she has taught Pilates for 15 years. Peak Performance has been named "Best of the Bay Area," "The premiere Pilates studio in the City," and "The top spot for Pilates" by the press. It is known for high quality, experienced teachers, respect for the classic method, and integration of medical knowledge into programs.