The Fitness Center at The Knickerbocker
The Knickerbocker's fitness center is praised by those who travel for a living. Out of 11 reviews tracked on TripExpert, 3 referenced the fitness center, like Oyster, Frommer's and Star Service.
The Knickerbocker 
Oyster
Frommer's
Star Service
Oyster "Stand-out features include a coffee bar, a popular rooftop terrace with great views, a high-end restaurant headed by celebrity chef Charlie Palmer, and an excellent fitness center, but there's no pool or full spa (in-room treatments can be arranged)"
Frommer's "On-site are two gyms (one for cardio, one for weights) and two Charlie Palmer Restaurants"
Star Service "The gym with great views up on floor 20 is a surprise in a hotel that prides itself on minimalism, though the lack of meeting space is no bombshell"
