The supportive staff of personal trainers, boot-camp instructors, and nutrition coaches at Infinity Fitness may be quick to give clients technical tips regarding exercise, but they’re even quicker to give words of encouragement. This kind of engagement helps exercisers get the most out of the gym’s offerings, which include boot-camp workouts as well as private and semiprivate personal-training sessions that track results five different ways. As noted on the website, staff members view clients as “walking billboards” for their programs' effectiveness. In return, the staff asks only that clients work hard and stand for weeks at a time by the highway.