Crunch Fitness - Polk St. in San Francisco is a gym that fuses fitness and fun in a really cool location within an old theater. It is described as a solid mid-to-upper gym with character, a lively vibe, and an upbeat, inclusive atmosphere that attracts people of all fitness levels. The space is clean, well-maintained, and offers a wide variety of equipment including miles of cardio, plenty of machines, free weights, top-notch equipment, and functional training areas. A major highlight is the awesome, energetic, fun, and motivating group fitness classes like spin and yoga. The staff are friendly, approachable, and helpful, with personal training noted for providing good advice on fitness and form, and customizing exercises for specific goals and injuries. Memberships are month-to-month and provide access to city-wide Crunch Fitness locations. While the gym can get crowded at peak hours and shows some signs of strain in operations, it is generally considered a worthwhile place to work out, making exercise feel less like a chore and more like an experience to look forward to.